linux/net/sched/cls_route.c
Cong Wang aaa908ffbe net_sched: switch to rcu_work
Commit 05f0fe6b74 ("RCU, workqueue: Implement rcu_work") introduces
new API's for dispatching work in a RCU callback. Now we can just
switch to the new API's for tc filters. This could get rid of a lot
of code.

Cc: Tejun Heo <tj@kernel.org>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-05-24 22:56:15 -04:00

683 lines
14 KiB
C

/*
* net/sched/cls_route.c ROUTE4 classifier.
*
* 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: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
*/
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/skbuff.h>
#include <net/dst.h>
#include <net/route.h>
#include <net/netlink.h>
#include <net/act_api.h>
#include <net/pkt_cls.h>
/*
* 1. For now we assume that route tags < 256.
* It allows to use direct table lookups, instead of hash tables.
* 2. For now we assume that "from TAG" and "fromdev DEV" statements
* are mutually exclusive.
* 3. "to TAG from ANY" has higher priority, than "to ANY from XXX"
*/
struct route4_fastmap {
struct route4_filter *filter;
u32 id;
int iif;
};
struct route4_head {
struct route4_fastmap fastmap[16];
struct route4_bucket __rcu *table[256 + 1];
struct rcu_head rcu;
};
struct route4_bucket {
/* 16 FROM buckets + 16 IIF buckets + 1 wildcard bucket */
struct route4_filter __rcu *ht[16 + 16 + 1];
struct rcu_head rcu;
};
struct route4_filter {
struct route4_filter __rcu *next;
u32 id;
int iif;
struct tcf_result res;
struct tcf_exts exts;
u32 handle;
struct route4_bucket *bkt;
struct tcf_proto *tp;
struct rcu_work rwork;
};
#define ROUTE4_FAILURE ((struct route4_filter *)(-1L))
static inline int route4_fastmap_hash(u32 id, int iif)
{
return id & 0xF;
}
static DEFINE_SPINLOCK(fastmap_lock);
static void
route4_reset_fastmap(struct route4_head *head)
{
spin_lock_bh(&fastmap_lock);
memset(head->fastmap, 0, sizeof(head->fastmap));
spin_unlock_bh(&fastmap_lock);
}
static void
route4_set_fastmap(struct route4_head *head, u32 id, int iif,
struct route4_filter *f)
{
int h = route4_fastmap_hash(id, iif);
/* fastmap updates must look atomic to aling id, iff, filter */
spin_lock_bh(&fastmap_lock);
head->fastmap[h].id = id;
head->fastmap[h].iif = iif;
head->fastmap[h].filter = f;
spin_unlock_bh(&fastmap_lock);
}
static inline int route4_hash_to(u32 id)
{
return id & 0xFF;
}
static inline int route4_hash_from(u32 id)
{
return (id >> 16) & 0xF;
}
static inline int route4_hash_iif(int iif)
{
return 16 + ((iif >> 16) & 0xF);
}
static inline int route4_hash_wild(void)
{
return 32;
}
#define ROUTE4_APPLY_RESULT() \
{ \
*res = f->res; \
if (tcf_exts_has_actions(&f->exts)) { \
int r = tcf_exts_exec(skb, &f->exts, res); \
if (r < 0) { \
dont_cache = 1; \
continue; \
} \
return r; \
} else if (!dont_cache) \
route4_set_fastmap(head, id, iif, f); \
return 0; \
}
static int route4_classify(struct sk_buff *skb, const struct tcf_proto *tp,
struct tcf_result *res)
{
struct route4_head *head = rcu_dereference_bh(tp->root);
struct dst_entry *dst;
struct route4_bucket *b;
struct route4_filter *f;
u32 id, h;
int iif, dont_cache = 0;
dst = skb_dst(skb);
if (!dst)
goto failure;
id = dst->tclassid;
iif = inet_iif(skb);
h = route4_fastmap_hash(id, iif);
spin_lock(&fastmap_lock);
if (id == head->fastmap[h].id &&
iif == head->fastmap[h].iif &&
(f = head->fastmap[h].filter) != NULL) {
if (f == ROUTE4_FAILURE) {
spin_unlock(&fastmap_lock);
goto failure;
}
*res = f->res;
spin_unlock(&fastmap_lock);
return 0;
}
spin_unlock(&fastmap_lock);
h = route4_hash_to(id);
restart:
b = rcu_dereference_bh(head->table[h]);
if (b) {
for (f = rcu_dereference_bh(b->ht[route4_hash_from(id)]);
f;
f = rcu_dereference_bh(f->next))
if (f->id == id)
ROUTE4_APPLY_RESULT();
for (f = rcu_dereference_bh(b->ht[route4_hash_iif(iif)]);
f;
f = rcu_dereference_bh(f->next))
if (f->iif == iif)
ROUTE4_APPLY_RESULT();
for (f = rcu_dereference_bh(b->ht[route4_hash_wild()]);
f;
f = rcu_dereference_bh(f->next))
ROUTE4_APPLY_RESULT();
}
if (h < 256) {
h = 256;
id &= ~0xFFFF;
goto restart;
}
if (!dont_cache)
route4_set_fastmap(head, id, iif, ROUTE4_FAILURE);
failure:
return -1;
}
static inline u32 to_hash(u32 id)
{
u32 h = id & 0xFF;
if (id & 0x8000)
h += 256;
return h;
}
static inline u32 from_hash(u32 id)
{
id &= 0xFFFF;
if (id == 0xFFFF)
return 32;
if (!(id & 0x8000)) {
if (id > 255)
return 256;
return id & 0xF;
}
return 16 + (id & 0xF);
}
static void *route4_get(struct tcf_proto *tp, u32 handle)
{
struct route4_head *head = rtnl_dereference(tp->root);
struct route4_bucket *b;
struct route4_filter *f;
unsigned int h1, h2;
h1 = to_hash(handle);
if (h1 > 256)
return NULL;
h2 = from_hash(handle >> 16);
if (h2 > 32)
return NULL;
b = rtnl_dereference(head->table[h1]);
if (b) {
for (f = rtnl_dereference(b->ht[h2]);
f;
f = rtnl_dereference(f->next))
if (f->handle == handle)
return f;
}
return NULL;
}
static int route4_init(struct tcf_proto *tp)
{
struct route4_head *head;
head = kzalloc(sizeof(struct route4_head), GFP_KERNEL);
if (head == NULL)
return -ENOBUFS;
rcu_assign_pointer(tp->root, head);
return 0;
}
static void __route4_delete_filter(struct route4_filter *f)
{
tcf_exts_destroy(&f->exts);
tcf_exts_put_net(&f->exts);
kfree(f);
}
static void route4_delete_filter_work(struct work_struct *work)
{
struct route4_filter *f = container_of(to_rcu_work(work),
struct route4_filter,
rwork);
rtnl_lock();
__route4_delete_filter(f);
rtnl_unlock();
}
static void route4_queue_work(struct route4_filter *f)
{
tcf_queue_work(&f->rwork, route4_delete_filter_work);
}
static void route4_destroy(struct tcf_proto *tp, struct netlink_ext_ack *extack)
{
struct route4_head *head = rtnl_dereference(tp->root);
int h1, h2;
if (head == NULL)
return;
for (h1 = 0; h1 <= 256; h1++) {
struct route4_bucket *b;
b = rtnl_dereference(head->table[h1]);
if (b) {
for (h2 = 0; h2 <= 32; h2++) {
struct route4_filter *f;
while ((f = rtnl_dereference(b->ht[h2])) != NULL) {
struct route4_filter *next;
next = rtnl_dereference(f->next);
RCU_INIT_POINTER(b->ht[h2], next);
tcf_unbind_filter(tp, &f->res);
if (tcf_exts_get_net(&f->exts))
route4_queue_work(f);
else
__route4_delete_filter(f);
}
}
RCU_INIT_POINTER(head->table[h1], NULL);
kfree_rcu(b, rcu);
}
}
kfree_rcu(head, rcu);
}
static int route4_delete(struct tcf_proto *tp, void *arg, bool *last,
struct netlink_ext_ack *extack)
{
struct route4_head *head = rtnl_dereference(tp->root);
struct route4_filter *f = arg;
struct route4_filter __rcu **fp;
struct route4_filter *nf;
struct route4_bucket *b;
unsigned int h = 0;
int i, h1;
if (!head || !f)
return -EINVAL;
h = f->handle;
b = f->bkt;
fp = &b->ht[from_hash(h >> 16)];
for (nf = rtnl_dereference(*fp); nf;
fp = &nf->next, nf = rtnl_dereference(*fp)) {
if (nf == f) {
/* unlink it */
RCU_INIT_POINTER(*fp, rtnl_dereference(f->next));
/* Remove any fastmap lookups that might ref filter
* notice we unlink'd the filter so we can't get it
* back in the fastmap.
*/
route4_reset_fastmap(head);
/* Delete it */
tcf_unbind_filter(tp, &f->res);
tcf_exts_get_net(&f->exts);
tcf_queue_work(&f->rwork, route4_delete_filter_work);
/* Strip RTNL protected tree */
for (i = 0; i <= 32; i++) {
struct route4_filter *rt;
rt = rtnl_dereference(b->ht[i]);
if (rt)
goto out;
}
/* OK, session has no flows */
RCU_INIT_POINTER(head->table[to_hash(h)], NULL);
kfree_rcu(b, rcu);
break;
}
}
out:
*last = true;
for (h1 = 0; h1 <= 256; h1++) {
if (rcu_access_pointer(head->table[h1])) {
*last = false;
break;
}
}
return 0;
}
static const struct nla_policy route4_policy[TCA_ROUTE4_MAX + 1] = {
[TCA_ROUTE4_CLASSID] = { .type = NLA_U32 },
[TCA_ROUTE4_TO] = { .type = NLA_U32 },
[TCA_ROUTE4_FROM] = { .type = NLA_U32 },
[TCA_ROUTE4_IIF] = { .type = NLA_U32 },
};
static int route4_set_parms(struct net *net, struct tcf_proto *tp,
unsigned long base, struct route4_filter *f,
u32 handle, struct route4_head *head,
struct nlattr **tb, struct nlattr *est, int new,
bool ovr, struct netlink_ext_ack *extack)
{
u32 id = 0, to = 0, nhandle = 0x8000;
struct route4_filter *fp;
unsigned int h1;
struct route4_bucket *b;
int err;
err = tcf_exts_validate(net, tp, tb, est, &f->exts, ovr, extack);
if (err < 0)
return err;
if (tb[TCA_ROUTE4_TO]) {
if (new && handle & 0x8000)
return -EINVAL;
to = nla_get_u32(tb[TCA_ROUTE4_TO]);
if (to > 0xFF)
return -EINVAL;
nhandle = to;
}
if (tb[TCA_ROUTE4_FROM]) {
if (tb[TCA_ROUTE4_IIF])
return -EINVAL;
id = nla_get_u32(tb[TCA_ROUTE4_FROM]);
if (id > 0xFF)
return -EINVAL;
nhandle |= id << 16;
} else if (tb[TCA_ROUTE4_IIF]) {
id = nla_get_u32(tb[TCA_ROUTE4_IIF]);
if (id > 0x7FFF)
return -EINVAL;
nhandle |= (id | 0x8000) << 16;
} else
nhandle |= 0xFFFF << 16;
if (handle && new) {
nhandle |= handle & 0x7F00;
if (nhandle != handle)
return -EINVAL;
}
h1 = to_hash(nhandle);
b = rtnl_dereference(head->table[h1]);
if (!b) {
b = kzalloc(sizeof(struct route4_bucket), GFP_KERNEL);
if (b == NULL)
return -ENOBUFS;
rcu_assign_pointer(head->table[h1], b);
} else {
unsigned int h2 = from_hash(nhandle >> 16);
for (fp = rtnl_dereference(b->ht[h2]);
fp;
fp = rtnl_dereference(fp->next))
if (fp->handle == f->handle)
return -EEXIST;
}
if (tb[TCA_ROUTE4_TO])
f->id = to;
if (tb[TCA_ROUTE4_FROM])
f->id = to | id<<16;
else if (tb[TCA_ROUTE4_IIF])
f->iif = id;
f->handle = nhandle;
f->bkt = b;
f->tp = tp;
if (tb[TCA_ROUTE4_CLASSID]) {
f->res.classid = nla_get_u32(tb[TCA_ROUTE4_CLASSID]);
tcf_bind_filter(tp, &f->res, base);
}
return 0;
}
static int route4_change(struct net *net, struct sk_buff *in_skb,
struct tcf_proto *tp, unsigned long base, u32 handle,
struct nlattr **tca, void **arg, bool ovr,
struct netlink_ext_ack *extack)
{
struct route4_head *head = rtnl_dereference(tp->root);
struct route4_filter __rcu **fp;
struct route4_filter *fold, *f1, *pfp, *f = NULL;
struct route4_bucket *b;
struct nlattr *opt = tca[TCA_OPTIONS];
struct nlattr *tb[TCA_ROUTE4_MAX + 1];
unsigned int h, th;
int err;
bool new = true;
if (opt == NULL)
return handle ? -EINVAL : 0;
err = nla_parse_nested(tb, TCA_ROUTE4_MAX, opt, route4_policy, NULL);
if (err < 0)
return err;
fold = *arg;
if (fold && handle && fold->handle != handle)
return -EINVAL;
err = -ENOBUFS;
f = kzalloc(sizeof(struct route4_filter), GFP_KERNEL);
if (!f)
goto errout;
err = tcf_exts_init(&f->exts, TCA_ROUTE4_ACT, TCA_ROUTE4_POLICE);
if (err < 0)
goto errout;
if (fold) {
f->id = fold->id;
f->iif = fold->iif;
f->res = fold->res;
f->handle = fold->handle;
f->tp = fold->tp;
f->bkt = fold->bkt;
new = false;
}
err = route4_set_parms(net, tp, base, f, handle, head, tb,
tca[TCA_RATE], new, ovr, extack);
if (err < 0)
goto errout;
h = from_hash(f->handle >> 16);
fp = &f->bkt->ht[h];
for (pfp = rtnl_dereference(*fp);
(f1 = rtnl_dereference(*fp)) != NULL;
fp = &f1->next)
if (f->handle < f1->handle)
break;
tcf_block_netif_keep_dst(tp->chain->block);
rcu_assign_pointer(f->next, f1);
rcu_assign_pointer(*fp, f);
if (fold && fold->handle && f->handle != fold->handle) {
th = to_hash(fold->handle);
h = from_hash(fold->handle >> 16);
b = rtnl_dereference(head->table[th]);
if (b) {
fp = &b->ht[h];
for (pfp = rtnl_dereference(*fp); pfp;
fp = &pfp->next, pfp = rtnl_dereference(*fp)) {
if (pfp == f) {
*fp = f->next;
break;
}
}
}
}
route4_reset_fastmap(head);
*arg = f;
if (fold) {
tcf_unbind_filter(tp, &fold->res);
tcf_exts_get_net(&fold->exts);
tcf_queue_work(&fold->rwork, route4_delete_filter_work);
}
return 0;
errout:
if (f)
tcf_exts_destroy(&f->exts);
kfree(f);
return err;
}
static void route4_walk(struct tcf_proto *tp, struct tcf_walker *arg)
{
struct route4_head *head = rtnl_dereference(tp->root);
unsigned int h, h1;
if (head == NULL)
arg->stop = 1;
if (arg->stop)
return;
for (h = 0; h <= 256; h++) {
struct route4_bucket *b = rtnl_dereference(head->table[h]);
if (b) {
for (h1 = 0; h1 <= 32; h1++) {
struct route4_filter *f;
for (f = rtnl_dereference(b->ht[h1]);
f;
f = rtnl_dereference(f->next)) {
if (arg->count < arg->skip) {
arg->count++;
continue;
}
if (arg->fn(tp, f, arg) < 0) {
arg->stop = 1;
return;
}
arg->count++;
}
}
}
}
}
static int route4_dump(struct net *net, struct tcf_proto *tp, void *fh,
struct sk_buff *skb, struct tcmsg *t)
{
struct route4_filter *f = fh;
struct nlattr *nest;
u32 id;
if (f == NULL)
return skb->len;
t->tcm_handle = f->handle;
nest = nla_nest_start(skb, TCA_OPTIONS);
if (nest == NULL)
goto nla_put_failure;
if (!(f->handle & 0x8000)) {
id = f->id & 0xFF;
if (nla_put_u32(skb, TCA_ROUTE4_TO, id))
goto nla_put_failure;
}
if (f->handle & 0x80000000) {
if ((f->handle >> 16) != 0xFFFF &&
nla_put_u32(skb, TCA_ROUTE4_IIF, f->iif))
goto nla_put_failure;
} else {
id = f->id >> 16;
if (nla_put_u32(skb, TCA_ROUTE4_FROM, id))
goto nla_put_failure;
}
if (f->res.classid &&
nla_put_u32(skb, TCA_ROUTE4_CLASSID, f->res.classid))
goto nla_put_failure;
if (tcf_exts_dump(skb, &f->exts) < 0)
goto nla_put_failure;
nla_nest_end(skb, nest);
if (tcf_exts_dump_stats(skb, &f->exts) < 0)
goto nla_put_failure;
return skb->len;
nla_put_failure:
nla_nest_cancel(skb, nest);
return -1;
}
static void route4_bind_class(void *fh, u32 classid, unsigned long cl)
{
struct route4_filter *f = fh;
if (f && f->res.classid == classid)
f->res.class = cl;
}
static struct tcf_proto_ops cls_route4_ops __read_mostly = {
.kind = "route",
.classify = route4_classify,
.init = route4_init,
.destroy = route4_destroy,
.get = route4_get,
.change = route4_change,
.delete = route4_delete,
.walk = route4_walk,
.dump = route4_dump,
.bind_class = route4_bind_class,
.owner = THIS_MODULE,
};
static int __init init_route4(void)
{
return register_tcf_proto_ops(&cls_route4_ops);
}
static void __exit exit_route4(void)
{
unregister_tcf_proto_ops(&cls_route4_ops);
}
module_init(init_route4)
module_exit(exit_route4)
MODULE_LICENSE("GPL");