linux/net/sched/cls_route.c
Cong Wang 1e052be69d net_sched: destroy proto tp when all filters are gone
Kernel automatically creates a tp for each
(kind, protocol, priority) tuple, which has handle 0,
when we add a new filter, but it still is left there
after we remove our own, unless we don't specify the
handle (literally means all the filters under
the tuple). For example this one is left:

  # tc filter show dev eth0
  filter parent 8001: protocol arp pref 49152 basic

The user-space is hard to clean up these for kernel
because filters like u32 are organized in a complex way.
So kernel is responsible to remove it after all filters
are gone.  Each type of filter has its own way to
store the filters, so each type has to provide its
way to check if all filters are gone.

Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: Cong Wang <cwang@twopensource.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Acked-by: Jamal Hadi Salim<jhs@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2015-03-09 15:35:55 -04:00

675 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_head rcu;
};
#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_is_available(&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;
if (head == NULL)
goto old_method;
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;
old_method:
if (id && (TC_H_MAJ(id) == 0 ||
!(TC_H_MAJ(id^tp->q->handle)))) {
res->classid = id;
res->class = 0;
return 0;
}
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 unsigned long 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;
if (!head)
return 0;
h1 = to_hash(handle);
if (h1 > 256)
return 0;
h2 = from_hash(handle >> 16);
if (h2 > 32)
return 0;
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 (unsigned long)f;
}
return 0;
}
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 rcu_head *head)
{
struct route4_filter *f = container_of(head, struct route4_filter, rcu);
tcf_exts_destroy(&f->exts);
kfree(f);
}
static bool route4_destroy(struct tcf_proto *tp, bool force)
{
struct route4_head *head = rtnl_dereference(tp->root);
int h1, h2;
if (head == NULL)
return true;
if (!force) {
for (h1 = 0; h1 <= 256; h1++) {
if (rcu_access_pointer(head->table[h1]))
return false;
}
}
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);
call_rcu(&f->rcu, route4_delete_filter);
}
}
RCU_INIT_POINTER(head->table[h1], NULL);
kfree_rcu(b, rcu);
}
}
RCU_INIT_POINTER(tp->root, NULL);
kfree_rcu(head, rcu);
return true;
}
static int route4_delete(struct tcf_proto *tp, unsigned long arg)
{
struct route4_head *head = rtnl_dereference(tp->root);
struct route4_filter *f = (struct route4_filter *)arg;
struct route4_filter __rcu **fp;
struct route4_filter *nf;
struct route4_bucket *b;
unsigned int h = 0;
int i;
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);
call_rcu(&f->rcu, route4_delete_filter);
/* Strip RTNL protected tree */
for (i = 0; i <= 32; i++) {
struct route4_filter *rt;
rt = rtnl_dereference(b->ht[i]);
if (rt)
return 0;
}
/* OK, session has no flows */
RCU_INIT_POINTER(head->table[to_hash(h)], NULL);
kfree_rcu(b, rcu);
return 0;
}
}
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)
{
int err;
u32 id = 0, to = 0, nhandle = 0x8000;
struct route4_filter *fp;
unsigned int h1;
struct route4_bucket *b;
struct tcf_exts e;
tcf_exts_init(&e, TCA_ROUTE4_ACT, TCA_ROUTE4_POLICE);
err = tcf_exts_validate(net, tp, tb, est, &e, ovr);
if (err < 0)
return err;
err = -EINVAL;
if (tb[TCA_ROUTE4_TO]) {
if (new && handle & 0x8000)
goto errout;
to = nla_get_u32(tb[TCA_ROUTE4_TO]);
if (to > 0xFF)
goto errout;
nhandle = to;
}
if (tb[TCA_ROUTE4_FROM]) {
if (tb[TCA_ROUTE4_IIF])
goto errout;
id = nla_get_u32(tb[TCA_ROUTE4_FROM]);
if (id > 0xFF)
goto errout;
nhandle |= id << 16;
} else if (tb[TCA_ROUTE4_IIF]) {
id = nla_get_u32(tb[TCA_ROUTE4_IIF]);
if (id > 0x7FFF)
goto errout;
nhandle |= (id | 0x8000) << 16;
} else
nhandle |= 0xFFFF << 16;
if (handle && new) {
nhandle |= handle & 0x7F00;
if (nhandle != handle)
goto errout;
}
h1 = to_hash(nhandle);
b = rtnl_dereference(head->table[h1]);
if (!b) {
err = -ENOBUFS;
b = kzalloc(sizeof(struct route4_bucket), GFP_KERNEL);
if (b == NULL)
goto errout;
rcu_assign_pointer(head->table[h1], b);
} else {
unsigned int h2 = from_hash(nhandle >> 16);
err = -EEXIST;
for (fp = rtnl_dereference(b->ht[h2]);
fp;
fp = rtnl_dereference(fp->next))
if (fp->handle == f->handle)
goto errout;
}
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);
}
tcf_exts_change(tp, &f->exts, &e);
return 0;
errout:
tcf_exts_destroy(&e);
return err;
}
static int route4_change(struct net *net, struct sk_buff *in_skb,
struct tcf_proto *tp, unsigned long base,
u32 handle,
struct nlattr **tca,
unsigned long *arg, bool ovr)
{
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);
if (err < 0)
return err;
fold = (struct route4_filter *)*arg;
if (fold && handle && fold->handle != handle)
return -EINVAL;
err = -ENOBUFS;
f = kzalloc(sizeof(struct route4_filter), GFP_KERNEL);
if (!f)
goto errout;
tcf_exts_init(&f->exts, TCA_ROUTE4_ACT, TCA_ROUTE4_POLICE);
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);
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;
netif_keep_dst(qdisc_dev(tp->q));
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 = (unsigned long)f;
if (fold) {
tcf_unbind_filter(tp, &fold->res);
call_rcu(&fold->rcu, route4_delete_filter);
}
return 0;
errout:
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, (unsigned long)f, arg) < 0) {
arg->stop = 1;
return;
}
arg->count++;
}
}
}
}
}
static int route4_dump(struct net *net, struct tcf_proto *tp, unsigned long fh,
struct sk_buff *skb, struct tcmsg *t)
{
struct route4_filter *f = (struct route4_filter *)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 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,
.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");