linux/net/sched/cls_fw.c
WANG Cong 4392053879 net_sched: remove useless NULL to tp->root
There is no need to NULL tp->root in ->destroy(), since tp is
going to be freed very soon, and existing readers are still
safe to read them.

For cls_route, we always init its tp->root, so it can't be NULL,
we can drop more useless code.

Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: John Fastabend <john.fastabend@gmail.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>
2017-04-21 13:58:15 -04:00

453 lines
9.6 KiB
C

/*
* net/sched/cls_fw.c Classifier mapping ipchains' fwmark to traffic class.
*
* 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>
*
* Changes:
* Karlis Peisenieks <karlis@mt.lv> : 990415 : fw_walk off by one
* Karlis Peisenieks <karlis@mt.lv> : 990415 : fw_delete killed all the filter (and kernel).
* Alex <alex@pilotsoft.com> : 2004xxyy: Added Action extension
*
* JHS: We should remove the CONFIG_NET_CLS_IND from here
* eventually when the meta match extension is made available
*
*/
#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/netlink.h>
#include <net/act_api.h>
#include <net/pkt_cls.h>
#define HTSIZE 256
struct fw_head {
u32 mask;
struct fw_filter __rcu *ht[HTSIZE];
struct rcu_head rcu;
};
struct fw_filter {
struct fw_filter __rcu *next;
u32 id;
struct tcf_result res;
#ifdef CONFIG_NET_CLS_IND
int ifindex;
#endif /* CONFIG_NET_CLS_IND */
struct tcf_exts exts;
struct tcf_proto *tp;
struct rcu_head rcu;
};
static u32 fw_hash(u32 handle)
{
handle ^= (handle >> 16);
handle ^= (handle >> 8);
return handle % HTSIZE;
}
static int fw_classify(struct sk_buff *skb, const struct tcf_proto *tp,
struct tcf_result *res)
{
struct fw_head *head = rcu_dereference_bh(tp->root);
struct fw_filter *f;
int r;
u32 id = skb->mark;
if (head != NULL) {
id &= head->mask;
for (f = rcu_dereference_bh(head->ht[fw_hash(id)]); f;
f = rcu_dereference_bh(f->next)) {
if (f->id == id) {
*res = f->res;
#ifdef CONFIG_NET_CLS_IND
if (!tcf_match_indev(skb, f->ifindex))
continue;
#endif /* CONFIG_NET_CLS_IND */
r = tcf_exts_exec(skb, &f->exts, res);
if (r < 0)
continue;
return r;
}
}
} else {
/* Old method: classify the packet using its skb mark. */
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 unsigned long fw_get(struct tcf_proto *tp, u32 handle)
{
struct fw_head *head = rtnl_dereference(tp->root);
struct fw_filter *f;
if (head == NULL)
return 0;
f = rtnl_dereference(head->ht[fw_hash(handle)]);
for (; f; f = rtnl_dereference(f->next)) {
if (f->id == handle)
return (unsigned long)f;
}
return 0;
}
static int fw_init(struct tcf_proto *tp)
{
/* We don't allocate fw_head here, because in the old method
* we don't need it at all.
*/
return 0;
}
static void fw_delete_filter(struct rcu_head *head)
{
struct fw_filter *f = container_of(head, struct fw_filter, rcu);
tcf_exts_destroy(&f->exts);
kfree(f);
}
static void fw_destroy(struct tcf_proto *tp)
{
struct fw_head *head = rtnl_dereference(tp->root);
struct fw_filter *f;
int h;
if (head == NULL)
return;
for (h = 0; h < HTSIZE; h++) {
while ((f = rtnl_dereference(head->ht[h])) != NULL) {
RCU_INIT_POINTER(head->ht[h],
rtnl_dereference(f->next));
tcf_unbind_filter(tp, &f->res);
call_rcu(&f->rcu, fw_delete_filter);
}
}
kfree_rcu(head, rcu);
}
static int fw_delete(struct tcf_proto *tp, unsigned long arg, bool *last)
{
struct fw_head *head = rtnl_dereference(tp->root);
struct fw_filter *f = (struct fw_filter *)arg;
struct fw_filter __rcu **fp;
struct fw_filter *pfp;
int ret = -EINVAL;
int h;
if (head == NULL || f == NULL)
goto out;
fp = &head->ht[fw_hash(f->id)];
for (pfp = rtnl_dereference(*fp); pfp;
fp = &pfp->next, pfp = rtnl_dereference(*fp)) {
if (pfp == f) {
RCU_INIT_POINTER(*fp, rtnl_dereference(f->next));
tcf_unbind_filter(tp, &f->res);
call_rcu(&f->rcu, fw_delete_filter);
ret = 0;
break;
}
}
*last = true;
for (h = 0; h < HTSIZE; h++) {
if (rcu_access_pointer(head->ht[h])) {
*last = false;
break;
}
}
out:
return ret;
}
static const struct nla_policy fw_policy[TCA_FW_MAX + 1] = {
[TCA_FW_CLASSID] = { .type = NLA_U32 },
[TCA_FW_INDEV] = { .type = NLA_STRING, .len = IFNAMSIZ },
[TCA_FW_MASK] = { .type = NLA_U32 },
};
static int
fw_change_attrs(struct net *net, struct tcf_proto *tp, struct fw_filter *f,
struct nlattr **tb, struct nlattr **tca, unsigned long base,
bool ovr)
{
struct fw_head *head = rtnl_dereference(tp->root);
struct tcf_exts e;
u32 mask;
int err;
err = tcf_exts_init(&e, TCA_FW_ACT, TCA_FW_POLICE);
if (err < 0)
return err;
err = tcf_exts_validate(net, tp, tb, tca[TCA_RATE], &e, ovr);
if (err < 0)
goto errout;
if (tb[TCA_FW_CLASSID]) {
f->res.classid = nla_get_u32(tb[TCA_FW_CLASSID]);
tcf_bind_filter(tp, &f->res, base);
}
#ifdef CONFIG_NET_CLS_IND
if (tb[TCA_FW_INDEV]) {
int ret;
ret = tcf_change_indev(net, tb[TCA_FW_INDEV]);
if (ret < 0) {
err = ret;
goto errout;
}
f->ifindex = ret;
}
#endif /* CONFIG_NET_CLS_IND */
err = -EINVAL;
if (tb[TCA_FW_MASK]) {
mask = nla_get_u32(tb[TCA_FW_MASK]);
if (mask != head->mask)
goto errout;
} else if (head->mask != 0xFFFFFFFF)
goto errout;
tcf_exts_change(tp, &f->exts, &e);
return 0;
errout:
tcf_exts_destroy(&e);
return err;
}
static int fw_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 fw_head *head = rtnl_dereference(tp->root);
struct fw_filter *f = (struct fw_filter *) *arg;
struct nlattr *opt = tca[TCA_OPTIONS];
struct nlattr *tb[TCA_FW_MAX + 1];
int err;
if (!opt)
return handle ? -EINVAL : 0; /* Succeed if it is old method. */
err = nla_parse_nested(tb, TCA_FW_MAX, opt, fw_policy, NULL);
if (err < 0)
return err;
if (f) {
struct fw_filter *pfp, *fnew;
struct fw_filter __rcu **fp;
if (f->id != handle && handle)
return -EINVAL;
fnew = kzalloc(sizeof(struct fw_filter), GFP_KERNEL);
if (!fnew)
return -ENOBUFS;
fnew->id = f->id;
fnew->res = f->res;
#ifdef CONFIG_NET_CLS_IND
fnew->ifindex = f->ifindex;
#endif /* CONFIG_NET_CLS_IND */
fnew->tp = f->tp;
err = tcf_exts_init(&fnew->exts, TCA_FW_ACT, TCA_FW_POLICE);
if (err < 0) {
kfree(fnew);
return err;
}
err = fw_change_attrs(net, tp, fnew, tb, tca, base, ovr);
if (err < 0) {
tcf_exts_destroy(&fnew->exts);
kfree(fnew);
return err;
}
fp = &head->ht[fw_hash(fnew->id)];
for (pfp = rtnl_dereference(*fp); pfp;
fp = &pfp->next, pfp = rtnl_dereference(*fp))
if (pfp == f)
break;
RCU_INIT_POINTER(fnew->next, rtnl_dereference(pfp->next));
rcu_assign_pointer(*fp, fnew);
tcf_unbind_filter(tp, &f->res);
call_rcu(&f->rcu, fw_delete_filter);
*arg = (unsigned long)fnew;
return err;
}
if (!handle)
return -EINVAL;
if (!head) {
u32 mask = 0xFFFFFFFF;
if (tb[TCA_FW_MASK])
mask = nla_get_u32(tb[TCA_FW_MASK]);
head = kzalloc(sizeof(*head), GFP_KERNEL);
if (!head)
return -ENOBUFS;
head->mask = mask;
rcu_assign_pointer(tp->root, head);
}
f = kzalloc(sizeof(struct fw_filter), GFP_KERNEL);
if (f == NULL)
return -ENOBUFS;
err = tcf_exts_init(&f->exts, TCA_FW_ACT, TCA_FW_POLICE);
if (err < 0)
goto errout;
f->id = handle;
f->tp = tp;
err = fw_change_attrs(net, tp, f, tb, tca, base, ovr);
if (err < 0)
goto errout;
RCU_INIT_POINTER(f->next, head->ht[fw_hash(handle)]);
rcu_assign_pointer(head->ht[fw_hash(handle)], f);
*arg = (unsigned long)f;
return 0;
errout:
tcf_exts_destroy(&f->exts);
kfree(f);
return err;
}
static void fw_walk(struct tcf_proto *tp, struct tcf_walker *arg)
{
struct fw_head *head = rtnl_dereference(tp->root);
int h;
if (head == NULL)
arg->stop = 1;
if (arg->stop)
return;
for (h = 0; h < HTSIZE; h++) {
struct fw_filter *f;
for (f = rtnl_dereference(head->ht[h]); 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 fw_dump(struct net *net, struct tcf_proto *tp, unsigned long fh,
struct sk_buff *skb, struct tcmsg *t)
{
struct fw_head *head = rtnl_dereference(tp->root);
struct fw_filter *f = (struct fw_filter *)fh;
struct nlattr *nest;
if (f == NULL)
return skb->len;
t->tcm_handle = f->id;
if (!f->res.classid && !tcf_exts_is_available(&f->exts))
return skb->len;
nest = nla_nest_start(skb, TCA_OPTIONS);
if (nest == NULL)
goto nla_put_failure;
if (f->res.classid &&
nla_put_u32(skb, TCA_FW_CLASSID, f->res.classid))
goto nla_put_failure;
#ifdef CONFIG_NET_CLS_IND
if (f->ifindex) {
struct net_device *dev;
dev = __dev_get_by_index(net, f->ifindex);
if (dev && nla_put_string(skb, TCA_FW_INDEV, dev->name))
goto nla_put_failure;
}
#endif /* CONFIG_NET_CLS_IND */
if (head->mask != 0xFFFFFFFF &&
nla_put_u32(skb, TCA_FW_MASK, head->mask))
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_fw_ops __read_mostly = {
.kind = "fw",
.classify = fw_classify,
.init = fw_init,
.destroy = fw_destroy,
.get = fw_get,
.change = fw_change,
.delete = fw_delete,
.walk = fw_walk,
.dump = fw_dump,
.owner = THIS_MODULE,
};
static int __init init_fw(void)
{
return register_tcf_proto_ops(&cls_fw_ops);
}
static void __exit exit_fw(void)
{
unregister_tcf_proto_ops(&cls_fw_ops);
}
module_init(init_fw)
module_exit(exit_fw)
MODULE_LICENSE("GPL");