linux/net/core/gen_stats.c
Ignacy Gawędzki 1c4cff0cf5 gen_stats.c: Duplicate xstats buffer for later use
The gnet_stats_copy_app() function gets called, more often than not, with its
second argument a pointer to an automatic variable in the caller's stack.
Therefore, to avoid copying garbage afterwards when calling
gnet_stats_finish_copy(), this data is better copied to a dynamically allocated
memory that gets freed after use.

[xiyou.wangcong@gmail.com: remove a useless kfree()]

Signed-off-by: Ignacy Gawędzki <ignacy.gawedzki@green-communications.fr>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2015-02-19 15:45:53 -05:00

365 lines
9.4 KiB
C

/*
* net/core/gen_stats.c
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*
* Authors: Thomas Graf <tgraf@suug.ch>
* Jamal Hadi Salim
* Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
*
* See Documentation/networking/gen_stats.txt
*/
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/socket.h>
#include <linux/rtnetlink.h>
#include <linux/gen_stats.h>
#include <net/netlink.h>
#include <net/gen_stats.h>
static inline int
gnet_stats_copy(struct gnet_dump *d, int type, void *buf, int size)
{
if (nla_put(d->skb, type, size, buf))
goto nla_put_failure;
return 0;
nla_put_failure:
kfree(d->xstats);
d->xstats = NULL;
d->xstats_len = 0;
spin_unlock_bh(d->lock);
return -1;
}
/**
* gnet_stats_start_copy_compat - start dumping procedure in compatibility mode
* @skb: socket buffer to put statistics TLVs into
* @type: TLV type for top level statistic TLV
* @tc_stats_type: TLV type for backward compatibility struct tc_stats TLV
* @xstats_type: TLV type for backward compatibility xstats TLV
* @lock: statistics lock
* @d: dumping handle
*
* Initializes the dumping handle, grabs the statistic lock and appends
* an empty TLV header to the socket buffer for use a container for all
* other statistic TLVS.
*
* The dumping handle is marked to be in backward compatibility mode telling
* all gnet_stats_copy_XXX() functions to fill a local copy of struct tc_stats.
*
* Returns 0 on success or -1 if the room in the socket buffer was not sufficient.
*/
int
gnet_stats_start_copy_compat(struct sk_buff *skb, int type, int tc_stats_type,
int xstats_type, spinlock_t *lock, struct gnet_dump *d)
__acquires(lock)
{
memset(d, 0, sizeof(*d));
spin_lock_bh(lock);
d->lock = lock;
if (type)
d->tail = (struct nlattr *)skb_tail_pointer(skb);
d->skb = skb;
d->compat_tc_stats = tc_stats_type;
d->compat_xstats = xstats_type;
if (d->tail)
return gnet_stats_copy(d, type, NULL, 0);
return 0;
}
EXPORT_SYMBOL(gnet_stats_start_copy_compat);
/**
* gnet_stats_start_copy_compat - start dumping procedure in compatibility mode
* @skb: socket buffer to put statistics TLVs into
* @type: TLV type for top level statistic TLV
* @lock: statistics lock
* @d: dumping handle
*
* Initializes the dumping handle, grabs the statistic lock and appends
* an empty TLV header to the socket buffer for use a container for all
* other statistic TLVS.
*
* Returns 0 on success or -1 if the room in the socket buffer was not sufficient.
*/
int
gnet_stats_start_copy(struct sk_buff *skb, int type, spinlock_t *lock,
struct gnet_dump *d)
{
return gnet_stats_start_copy_compat(skb, type, 0, 0, lock, d);
}
EXPORT_SYMBOL(gnet_stats_start_copy);
static void
__gnet_stats_copy_basic_cpu(struct gnet_stats_basic_packed *bstats,
struct gnet_stats_basic_cpu __percpu *cpu)
{
int i;
for_each_possible_cpu(i) {
struct gnet_stats_basic_cpu *bcpu = per_cpu_ptr(cpu, i);
unsigned int start;
u64 bytes;
u32 packets;
do {
start = u64_stats_fetch_begin_irq(&bcpu->syncp);
bytes = bcpu->bstats.bytes;
packets = bcpu->bstats.packets;
} while (u64_stats_fetch_retry_irq(&bcpu->syncp, start));
bstats->bytes += bytes;
bstats->packets += packets;
}
}
void
__gnet_stats_copy_basic(struct gnet_stats_basic_packed *bstats,
struct gnet_stats_basic_cpu __percpu *cpu,
struct gnet_stats_basic_packed *b)
{
if (cpu) {
__gnet_stats_copy_basic_cpu(bstats, cpu);
} else {
bstats->bytes = b->bytes;
bstats->packets = b->packets;
}
}
EXPORT_SYMBOL(__gnet_stats_copy_basic);
/**
* gnet_stats_copy_basic - copy basic statistics into statistic TLV
* @d: dumping handle
* @b: basic statistics
*
* Appends the basic statistics to the top level TLV created by
* gnet_stats_start_copy().
*
* Returns 0 on success or -1 with the statistic lock released
* if the room in the socket buffer was not sufficient.
*/
int
gnet_stats_copy_basic(struct gnet_dump *d,
struct gnet_stats_basic_cpu __percpu *cpu,
struct gnet_stats_basic_packed *b)
{
struct gnet_stats_basic_packed bstats = {0};
__gnet_stats_copy_basic(&bstats, cpu, b);
if (d->compat_tc_stats) {
d->tc_stats.bytes = bstats.bytes;
d->tc_stats.packets = bstats.packets;
}
if (d->tail) {
struct gnet_stats_basic sb;
memset(&sb, 0, sizeof(sb));
sb.bytes = bstats.bytes;
sb.packets = bstats.packets;
return gnet_stats_copy(d, TCA_STATS_BASIC, &sb, sizeof(sb));
}
return 0;
}
EXPORT_SYMBOL(gnet_stats_copy_basic);
/**
* gnet_stats_copy_rate_est - copy rate estimator statistics into statistics TLV
* @d: dumping handle
* @b: basic statistics
* @r: rate estimator statistics
*
* Appends the rate estimator statistics to the top level TLV created by
* gnet_stats_start_copy().
*
* Returns 0 on success or -1 with the statistic lock released
* if the room in the socket buffer was not sufficient.
*/
int
gnet_stats_copy_rate_est(struct gnet_dump *d,
const struct gnet_stats_basic_packed *b,
struct gnet_stats_rate_est64 *r)
{
struct gnet_stats_rate_est est;
int res;
if (b && !gen_estimator_active(b, r))
return 0;
est.bps = min_t(u64, UINT_MAX, r->bps);
/* we have some time before reaching 2^32 packets per second */
est.pps = r->pps;
if (d->compat_tc_stats) {
d->tc_stats.bps = est.bps;
d->tc_stats.pps = est.pps;
}
if (d->tail) {
res = gnet_stats_copy(d, TCA_STATS_RATE_EST, &est, sizeof(est));
if (res < 0 || est.bps == r->bps)
return res;
/* emit 64bit stats only if needed */
return gnet_stats_copy(d, TCA_STATS_RATE_EST64, r, sizeof(*r));
}
return 0;
}
EXPORT_SYMBOL(gnet_stats_copy_rate_est);
static void
__gnet_stats_copy_queue_cpu(struct gnet_stats_queue *qstats,
const struct gnet_stats_queue __percpu *q)
{
int i;
for_each_possible_cpu(i) {
const struct gnet_stats_queue *qcpu = per_cpu_ptr(q, i);
qstats->qlen = 0;
qstats->backlog += qcpu->backlog;
qstats->drops += qcpu->drops;
qstats->requeues += qcpu->requeues;
qstats->overlimits += qcpu->overlimits;
}
}
static void __gnet_stats_copy_queue(struct gnet_stats_queue *qstats,
const struct gnet_stats_queue __percpu *cpu,
const struct gnet_stats_queue *q,
__u32 qlen)
{
if (cpu) {
__gnet_stats_copy_queue_cpu(qstats, cpu);
} else {
qstats->qlen = q->qlen;
qstats->backlog = q->backlog;
qstats->drops = q->drops;
qstats->requeues = q->requeues;
qstats->overlimits = q->overlimits;
}
qstats->qlen = qlen;
}
/**
* gnet_stats_copy_queue - copy queue statistics into statistics TLV
* @d: dumping handle
* @cpu_q: per cpu queue statistics
* @q: queue statistics
* @qlen: queue length statistics
*
* Appends the queue statistics to the top level TLV created by
* gnet_stats_start_copy(). Using per cpu queue statistics if
* they are available.
*
* Returns 0 on success or -1 with the statistic lock released
* if the room in the socket buffer was not sufficient.
*/
int
gnet_stats_copy_queue(struct gnet_dump *d,
struct gnet_stats_queue __percpu *cpu_q,
struct gnet_stats_queue *q, __u32 qlen)
{
struct gnet_stats_queue qstats = {0};
__gnet_stats_copy_queue(&qstats, cpu_q, q, qlen);
if (d->compat_tc_stats) {
d->tc_stats.drops = qstats.drops;
d->tc_stats.qlen = qstats.qlen;
d->tc_stats.backlog = qstats.backlog;
d->tc_stats.overlimits = qstats.overlimits;
}
if (d->tail)
return gnet_stats_copy(d, TCA_STATS_QUEUE,
&qstats, sizeof(qstats));
return 0;
}
EXPORT_SYMBOL(gnet_stats_copy_queue);
/**
* gnet_stats_copy_app - copy application specific statistics into statistics TLV
* @d: dumping handle
* @st: application specific statistics data
* @len: length of data
*
* Appends the application specific statistics to the top level TLV created by
* gnet_stats_start_copy() and remembers the data for XSTATS if the dumping
* handle is in backward compatibility mode.
*
* Returns 0 on success or -1 with the statistic lock released
* if the room in the socket buffer was not sufficient.
*/
int
gnet_stats_copy_app(struct gnet_dump *d, void *st, int len)
{
if (d->compat_xstats) {
d->xstats = kmemdup(st, len, GFP_ATOMIC);
if (!d->xstats)
goto err_out;
d->xstats_len = len;
}
if (d->tail)
return gnet_stats_copy(d, TCA_STATS_APP, st, len);
return 0;
err_out:
d->xstats_len = 0;
spin_unlock_bh(d->lock);
return -1;
}
EXPORT_SYMBOL(gnet_stats_copy_app);
/**
* gnet_stats_finish_copy - finish dumping procedure
* @d: dumping handle
*
* Corrects the length of the top level TLV to include all TLVs added
* by gnet_stats_copy_XXX() calls. Adds the backward compatibility TLVs
* if gnet_stats_start_copy_compat() was used and releases the statistics
* lock.
*
* Returns 0 on success or -1 with the statistic lock released
* if the room in the socket buffer was not sufficient.
*/
int
gnet_stats_finish_copy(struct gnet_dump *d)
{
if (d->tail)
d->tail->nla_len = skb_tail_pointer(d->skb) - (u8 *)d->tail;
if (d->compat_tc_stats)
if (gnet_stats_copy(d, d->compat_tc_stats, &d->tc_stats,
sizeof(d->tc_stats)) < 0)
return -1;
if (d->compat_xstats && d->xstats) {
if (gnet_stats_copy(d, d->compat_xstats, d->xstats,
d->xstats_len) < 0)
return -1;
}
kfree(d->xstats);
d->xstats = NULL;
d->xstats_len = 0;
spin_unlock_bh(d->lock);
return 0;
}
EXPORT_SYMBOL(gnet_stats_finish_copy);