linux-stable/net/sched/act_ipt.c
Alexey Dobriyan c7d03a00b5 netns: make struct pernet_operations::id unsigned int
Make struct pernet_operations::id unsigned.

There are 2 reasons to do so:

1)
This field is really an index into an zero based array and
thus is unsigned entity. Using negative value is out-of-bound
access by definition.

2)
On x86_64 unsigned 32-bit data which are mixed with pointers
via array indexing or offsets added or subtracted to pointers
are preffered to signed 32-bit data.

"int" being used as an array index needs to be sign-extended
to 64-bit before being used.

	void f(long *p, int i)
	{
		g(p[i]);
	}

  roughly translates to

	movsx	rsi, esi
	mov	rdi, [rsi+...]
	call 	g

MOVSX is 3 byte instruction which isn't necessary if the variable is
unsigned because x86_64 is zero extending by default.

Now, there is net_generic() function which, you guessed it right, uses
"int" as an array index:

	static inline void *net_generic(const struct net *net, int id)
	{
		...
		ptr = ng->ptr[id - 1];
		...
	}

And this function is used a lot, so those sign extensions add up.

Patch snipes ~1730 bytes on allyesconfig kernel (without all junk
messing with code generation):

	add/remove: 0/0 grow/shrink: 70/598 up/down: 396/-2126 (-1730)

Unfortunately some functions actually grow bigger.
This is a semmingly random artefact of code generation with register
allocator being used differently. gcc decides that some variable
needs to live in new r8+ registers and every access now requires REX
prefix. Or it is shifted into r12, so [r12+0] addressing mode has to be
used which is longer than [r8]

However, overall balance is in negative direction:

	add/remove: 0/0 grow/shrink: 70/598 up/down: 396/-2126 (-1730)
	function                                     old     new   delta
	nfsd4_lock                                  3886    3959     +73
	tipc_link_build_proto_msg                   1096    1140     +44
	mac80211_hwsim_new_radio                    2776    2808     +32
	tipc_mon_rcv                                1032    1058     +26
	svcauth_gss_legacy_init                     1413    1429     +16
	tipc_bcbase_select_primary                   379     392     +13
	nfsd4_exchange_id                           1247    1260     +13
	nfsd4_setclientid_confirm                    782     793     +11
		...
	put_client_renew_locked                      494     480     -14
	ip_set_sockfn_get                            730     716     -14
	geneve_sock_add                              829     813     -16
	nfsd4_sequence_done                          721     703     -18
	nlmclnt_lookup_host                          708     686     -22
	nfsd4_lockt                                 1085    1063     -22
	nfs_get_client                              1077    1050     -27
	tcf_bpf_init                                1106    1076     -30
	nfsd4_encode_fattr                          5997    5930     -67
	Total: Before=154856051, After=154854321, chg -0.00%

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-11-18 10:59:15 -05:00

434 lines
10 KiB
C

/*
* net/sched/act_ipt.c iptables target interface
*
*TODO: Add other tables. For now we only support the ipv4 table targets
*
* 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.
*
* Copyright: Jamal Hadi Salim (2002-13)
*/
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/skbuff.h>
#include <linux/rtnetlink.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <net/netlink.h>
#include <net/pkt_sched.h>
#include <linux/tc_act/tc_ipt.h>
#include <net/tc_act/tc_ipt.h>
#include <linux/netfilter_ipv4/ip_tables.h>
#define IPT_TAB_MASK 15
static unsigned int ipt_net_id;
static struct tc_action_ops act_ipt_ops;
static unsigned int xt_net_id;
static struct tc_action_ops act_xt_ops;
static int ipt_init_target(struct xt_entry_target *t, char *table,
unsigned int hook)
{
struct xt_tgchk_param par;
struct xt_target *target;
int ret = 0;
target = xt_request_find_target(AF_INET, t->u.user.name,
t->u.user.revision);
if (IS_ERR(target))
return PTR_ERR(target);
t->u.kernel.target = target;
par.table = table;
par.entryinfo = NULL;
par.target = target;
par.targinfo = t->data;
par.hook_mask = hook;
par.family = NFPROTO_IPV4;
ret = xt_check_target(&par, t->u.target_size - sizeof(*t), 0, false);
if (ret < 0) {
module_put(t->u.kernel.target->me);
return ret;
}
return 0;
}
static void ipt_destroy_target(struct xt_entry_target *t)
{
struct xt_tgdtor_param par = {
.target = t->u.kernel.target,
.targinfo = t->data,
.family = NFPROTO_IPV4,
};
if (par.target->destroy != NULL)
par.target->destroy(&par);
module_put(par.target->me);
}
static void tcf_ipt_release(struct tc_action *a, int bind)
{
struct tcf_ipt *ipt = to_ipt(a);
ipt_destroy_target(ipt->tcfi_t);
kfree(ipt->tcfi_tname);
kfree(ipt->tcfi_t);
}
static const struct nla_policy ipt_policy[TCA_IPT_MAX + 1] = {
[TCA_IPT_TABLE] = { .type = NLA_STRING, .len = IFNAMSIZ },
[TCA_IPT_HOOK] = { .type = NLA_U32 },
[TCA_IPT_INDEX] = { .type = NLA_U32 },
[TCA_IPT_TARG] = { .len = sizeof(struct xt_entry_target) },
};
static int __tcf_ipt_init(struct tc_action_net *tn, struct nlattr *nla,
struct nlattr *est, struct tc_action **a,
const struct tc_action_ops *ops, int ovr, int bind)
{
struct nlattr *tb[TCA_IPT_MAX + 1];
struct tcf_ipt *ipt;
struct xt_entry_target *td, *t;
char *tname;
bool exists = false;
int ret = 0, err;
u32 hook = 0;
u32 index = 0;
if (nla == NULL)
return -EINVAL;
err = nla_parse_nested(tb, TCA_IPT_MAX, nla, ipt_policy);
if (err < 0)
return err;
if (tb[TCA_IPT_INDEX] != NULL)
index = nla_get_u32(tb[TCA_IPT_INDEX]);
exists = tcf_hash_check(tn, index, a, bind);
if (exists && bind)
return 0;
if (tb[TCA_IPT_HOOK] == NULL || tb[TCA_IPT_TARG] == NULL) {
if (exists)
tcf_hash_release(*a, bind);
return -EINVAL;
}
td = (struct xt_entry_target *)nla_data(tb[TCA_IPT_TARG]);
if (nla_len(tb[TCA_IPT_TARG]) < td->u.target_size) {
if (exists)
tcf_hash_release(*a, bind);
return -EINVAL;
}
if (!exists) {
ret = tcf_hash_create(tn, index, est, a, ops, bind,
false);
if (ret)
return ret;
ret = ACT_P_CREATED;
} else {
if (bind)/* dont override defaults */
return 0;
tcf_hash_release(*a, bind);
if (!ovr)
return -EEXIST;
}
hook = nla_get_u32(tb[TCA_IPT_HOOK]);
err = -ENOMEM;
tname = kmalloc(IFNAMSIZ, GFP_KERNEL);
if (unlikely(!tname))
goto err1;
if (tb[TCA_IPT_TABLE] == NULL ||
nla_strlcpy(tname, tb[TCA_IPT_TABLE], IFNAMSIZ) >= IFNAMSIZ)
strcpy(tname, "mangle");
t = kmemdup(td, td->u.target_size, GFP_KERNEL);
if (unlikely(!t))
goto err2;
err = ipt_init_target(t, tname, hook);
if (err < 0)
goto err3;
ipt = to_ipt(*a);
spin_lock_bh(&ipt->tcf_lock);
if (ret != ACT_P_CREATED) {
ipt_destroy_target(ipt->tcfi_t);
kfree(ipt->tcfi_tname);
kfree(ipt->tcfi_t);
}
ipt->tcfi_tname = tname;
ipt->tcfi_t = t;
ipt->tcfi_hook = hook;
spin_unlock_bh(&ipt->tcf_lock);
if (ret == ACT_P_CREATED)
tcf_hash_insert(tn, *a);
return ret;
err3:
kfree(t);
err2:
kfree(tname);
err1:
if (ret == ACT_P_CREATED)
tcf_hash_cleanup(*a, est);
return err;
}
static int tcf_ipt_init(struct net *net, struct nlattr *nla,
struct nlattr *est, struct tc_action **a, int ovr,
int bind)
{
struct tc_action_net *tn = net_generic(net, ipt_net_id);
return __tcf_ipt_init(tn, nla, est, a, &act_ipt_ops, ovr, bind);
}
static int tcf_xt_init(struct net *net, struct nlattr *nla,
struct nlattr *est, struct tc_action **a, int ovr,
int bind)
{
struct tc_action_net *tn = net_generic(net, xt_net_id);
return __tcf_ipt_init(tn, nla, est, a, &act_xt_ops, ovr, bind);
}
static int tcf_ipt(struct sk_buff *skb, const struct tc_action *a,
struct tcf_result *res)
{
int ret = 0, result = 0;
struct tcf_ipt *ipt = to_ipt(a);
struct xt_action_param par;
struct nf_hook_state state = {
.net = dev_net(skb->dev),
.in = skb->dev,
.hook = ipt->tcfi_hook,
.pf = NFPROTO_IPV4,
};
if (skb_unclone(skb, GFP_ATOMIC))
return TC_ACT_UNSPEC;
spin_lock(&ipt->tcf_lock);
tcf_lastuse_update(&ipt->tcf_tm);
bstats_update(&ipt->tcf_bstats, skb);
/* yes, we have to worry about both in and out dev
* worry later - danger - this API seems to have changed
* from earlier kernels
*/
par.state = &state;
par.target = ipt->tcfi_t->u.kernel.target;
par.targinfo = ipt->tcfi_t->data;
ret = par.target->target(skb, &par);
switch (ret) {
case NF_ACCEPT:
result = TC_ACT_OK;
break;
case NF_DROP:
result = TC_ACT_SHOT;
ipt->tcf_qstats.drops++;
break;
case XT_CONTINUE:
result = TC_ACT_PIPE;
break;
default:
net_notice_ratelimited("tc filter: Bogus netfilter code %d assume ACCEPT\n",
ret);
result = TC_ACT_OK;
break;
}
spin_unlock(&ipt->tcf_lock);
return result;
}
static int tcf_ipt_dump(struct sk_buff *skb, struct tc_action *a, int bind,
int ref)
{
unsigned char *b = skb_tail_pointer(skb);
struct tcf_ipt *ipt = to_ipt(a);
struct xt_entry_target *t;
struct tcf_t tm;
struct tc_cnt c;
/* for simple targets kernel size == user size
* user name = target name
* for foolproof you need to not assume this
*/
t = kmemdup(ipt->tcfi_t, ipt->tcfi_t->u.user.target_size, GFP_ATOMIC);
if (unlikely(!t))
goto nla_put_failure;
c.bindcnt = ipt->tcf_bindcnt - bind;
c.refcnt = ipt->tcf_refcnt - ref;
strcpy(t->u.user.name, ipt->tcfi_t->u.kernel.target->name);
if (nla_put(skb, TCA_IPT_TARG, ipt->tcfi_t->u.user.target_size, t) ||
nla_put_u32(skb, TCA_IPT_INDEX, ipt->tcf_index) ||
nla_put_u32(skb, TCA_IPT_HOOK, ipt->tcfi_hook) ||
nla_put(skb, TCA_IPT_CNT, sizeof(struct tc_cnt), &c) ||
nla_put_string(skb, TCA_IPT_TABLE, ipt->tcfi_tname))
goto nla_put_failure;
tcf_tm_dump(&tm, &ipt->tcf_tm);
if (nla_put_64bit(skb, TCA_IPT_TM, sizeof(tm), &tm, TCA_IPT_PAD))
goto nla_put_failure;
kfree(t);
return skb->len;
nla_put_failure:
nlmsg_trim(skb, b);
kfree(t);
return -1;
}
static int tcf_ipt_walker(struct net *net, struct sk_buff *skb,
struct netlink_callback *cb, int type,
const struct tc_action_ops *ops)
{
struct tc_action_net *tn = net_generic(net, ipt_net_id);
return tcf_generic_walker(tn, skb, cb, type, ops);
}
static int tcf_ipt_search(struct net *net, struct tc_action **a, u32 index)
{
struct tc_action_net *tn = net_generic(net, ipt_net_id);
return tcf_hash_search(tn, a, index);
}
static struct tc_action_ops act_ipt_ops = {
.kind = "ipt",
.type = TCA_ACT_IPT,
.owner = THIS_MODULE,
.act = tcf_ipt,
.dump = tcf_ipt_dump,
.cleanup = tcf_ipt_release,
.init = tcf_ipt_init,
.walk = tcf_ipt_walker,
.lookup = tcf_ipt_search,
.size = sizeof(struct tcf_ipt),
};
static __net_init int ipt_init_net(struct net *net)
{
struct tc_action_net *tn = net_generic(net, ipt_net_id);
return tc_action_net_init(tn, &act_ipt_ops, IPT_TAB_MASK);
}
static void __net_exit ipt_exit_net(struct net *net)
{
struct tc_action_net *tn = net_generic(net, ipt_net_id);
tc_action_net_exit(tn);
}
static struct pernet_operations ipt_net_ops = {
.init = ipt_init_net,
.exit = ipt_exit_net,
.id = &ipt_net_id,
.size = sizeof(struct tc_action_net),
};
static int tcf_xt_walker(struct net *net, struct sk_buff *skb,
struct netlink_callback *cb, int type,
const struct tc_action_ops *ops)
{
struct tc_action_net *tn = net_generic(net, xt_net_id);
return tcf_generic_walker(tn, skb, cb, type, ops);
}
static int tcf_xt_search(struct net *net, struct tc_action **a, u32 index)
{
struct tc_action_net *tn = net_generic(net, xt_net_id);
return tcf_hash_search(tn, a, index);
}
static struct tc_action_ops act_xt_ops = {
.kind = "xt",
.type = TCA_ACT_XT,
.owner = THIS_MODULE,
.act = tcf_ipt,
.dump = tcf_ipt_dump,
.cleanup = tcf_ipt_release,
.init = tcf_xt_init,
.walk = tcf_xt_walker,
.lookup = tcf_xt_search,
.size = sizeof(struct tcf_ipt),
};
static __net_init int xt_init_net(struct net *net)
{
struct tc_action_net *tn = net_generic(net, xt_net_id);
return tc_action_net_init(tn, &act_xt_ops, IPT_TAB_MASK);
}
static void __net_exit xt_exit_net(struct net *net)
{
struct tc_action_net *tn = net_generic(net, xt_net_id);
tc_action_net_exit(tn);
}
static struct pernet_operations xt_net_ops = {
.init = xt_init_net,
.exit = xt_exit_net,
.id = &xt_net_id,
.size = sizeof(struct tc_action_net),
};
MODULE_AUTHOR("Jamal Hadi Salim(2002-13)");
MODULE_DESCRIPTION("Iptables target actions");
MODULE_LICENSE("GPL");
MODULE_ALIAS("act_xt");
static int __init ipt_init_module(void)
{
int ret1, ret2;
ret1 = tcf_register_action(&act_xt_ops, &xt_net_ops);
if (ret1 < 0)
pr_err("Failed to load xt action\n");
ret2 = tcf_register_action(&act_ipt_ops, &ipt_net_ops);
if (ret2 < 0)
pr_err("Failed to load ipt action\n");
if (ret1 < 0 && ret2 < 0) {
return ret1;
} else
return 0;
}
static void __exit ipt_cleanup_module(void)
{
tcf_unregister_action(&act_ipt_ops, &ipt_net_ops);
tcf_unregister_action(&act_xt_ops, &xt_net_ops);
}
module_init(ipt_init_module);
module_exit(ipt_cleanup_module);