linux/net/sched/act_vlan.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

307 lines
7.2 KiB
C

/*
* Copyright (c) 2014 Jiri Pirko <jiri@resnulli.us>
*
* 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.
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/skbuff.h>
#include <linux/rtnetlink.h>
#include <linux/if_vlan.h>
#include <net/netlink.h>
#include <net/pkt_sched.h>
#include <linux/tc_act/tc_vlan.h>
#include <net/tc_act/tc_vlan.h>
#define VLAN_TAB_MASK 15
static unsigned int vlan_net_id;
static struct tc_action_ops act_vlan_ops;
static int tcf_vlan(struct sk_buff *skb, const struct tc_action *a,
struct tcf_result *res)
{
struct tcf_vlan *v = to_vlan(a);
int action;
int err;
u16 tci;
spin_lock(&v->tcf_lock);
tcf_lastuse_update(&v->tcf_tm);
bstats_update(&v->tcf_bstats, skb);
action = v->tcf_action;
/* Ensure 'data' points at mac_header prior calling vlan manipulating
* functions.
*/
if (skb_at_tc_ingress(skb))
skb_push_rcsum(skb, skb->mac_len);
switch (v->tcfv_action) {
case TCA_VLAN_ACT_POP:
err = skb_vlan_pop(skb);
if (err)
goto drop;
break;
case TCA_VLAN_ACT_PUSH:
err = skb_vlan_push(skb, v->tcfv_push_proto, v->tcfv_push_vid |
(v->tcfv_push_prio << VLAN_PRIO_SHIFT));
if (err)
goto drop;
break;
case TCA_VLAN_ACT_MODIFY:
/* No-op if no vlan tag (either hw-accel or in-payload) */
if (!skb_vlan_tagged(skb))
goto unlock;
/* extract existing tag (and guarantee no hw-accel tag) */
if (skb_vlan_tag_present(skb)) {
tci = skb_vlan_tag_get(skb);
skb->vlan_tci = 0;
} else {
/* in-payload vlan tag, pop it */
err = __skb_vlan_pop(skb, &tci);
if (err)
goto drop;
}
/* replace the vid */
tci = (tci & ~VLAN_VID_MASK) | v->tcfv_push_vid;
/* replace prio bits, if tcfv_push_prio specified */
if (v->tcfv_push_prio) {
tci &= ~VLAN_PRIO_MASK;
tci |= v->tcfv_push_prio << VLAN_PRIO_SHIFT;
}
/* put updated tci as hwaccel tag */
__vlan_hwaccel_put_tag(skb, v->tcfv_push_proto, tci);
break;
default:
BUG();
}
goto unlock;
drop:
action = TC_ACT_SHOT;
v->tcf_qstats.drops++;
unlock:
if (skb_at_tc_ingress(skb))
skb_pull_rcsum(skb, skb->mac_len);
spin_unlock(&v->tcf_lock);
return action;
}
static const struct nla_policy vlan_policy[TCA_VLAN_MAX + 1] = {
[TCA_VLAN_PARMS] = { .len = sizeof(struct tc_vlan) },
[TCA_VLAN_PUSH_VLAN_ID] = { .type = NLA_U16 },
[TCA_VLAN_PUSH_VLAN_PROTOCOL] = { .type = NLA_U16 },
[TCA_VLAN_PUSH_VLAN_PRIORITY] = { .type = NLA_U8 },
};
static int tcf_vlan_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, vlan_net_id);
struct nlattr *tb[TCA_VLAN_MAX + 1];
struct tc_vlan *parm;
struct tcf_vlan *v;
int action;
__be16 push_vid = 0;
__be16 push_proto = 0;
u8 push_prio = 0;
bool exists = false;
int ret = 0, err;
if (!nla)
return -EINVAL;
err = nla_parse_nested(tb, TCA_VLAN_MAX, nla, vlan_policy);
if (err < 0)
return err;
if (!tb[TCA_VLAN_PARMS])
return -EINVAL;
parm = nla_data(tb[TCA_VLAN_PARMS]);
exists = tcf_hash_check(tn, parm->index, a, bind);
if (exists && bind)
return 0;
switch (parm->v_action) {
case TCA_VLAN_ACT_POP:
break;
case TCA_VLAN_ACT_PUSH:
case TCA_VLAN_ACT_MODIFY:
if (!tb[TCA_VLAN_PUSH_VLAN_ID]) {
if (exists)
tcf_hash_release(*a, bind);
return -EINVAL;
}
push_vid = nla_get_u16(tb[TCA_VLAN_PUSH_VLAN_ID]);
if (push_vid >= VLAN_VID_MASK) {
if (exists)
tcf_hash_release(*a, bind);
return -ERANGE;
}
if (tb[TCA_VLAN_PUSH_VLAN_PROTOCOL]) {
push_proto = nla_get_be16(tb[TCA_VLAN_PUSH_VLAN_PROTOCOL]);
switch (push_proto) {
case htons(ETH_P_8021Q):
case htons(ETH_P_8021AD):
break;
default:
return -EPROTONOSUPPORT;
}
} else {
push_proto = htons(ETH_P_8021Q);
}
if (tb[TCA_VLAN_PUSH_VLAN_PRIORITY])
push_prio = nla_get_u8(tb[TCA_VLAN_PUSH_VLAN_PRIORITY]);
break;
default:
if (exists)
tcf_hash_release(*a, bind);
return -EINVAL;
}
action = parm->v_action;
if (!exists) {
ret = tcf_hash_create(tn, parm->index, est, a,
&act_vlan_ops, bind, false);
if (ret)
return ret;
ret = ACT_P_CREATED;
} else {
tcf_hash_release(*a, bind);
if (!ovr)
return -EEXIST;
}
v = to_vlan(*a);
spin_lock_bh(&v->tcf_lock);
v->tcfv_action = action;
v->tcfv_push_vid = push_vid;
v->tcfv_push_prio = push_prio;
v->tcfv_push_proto = push_proto;
v->tcf_action = parm->action;
spin_unlock_bh(&v->tcf_lock);
if (ret == ACT_P_CREATED)
tcf_hash_insert(tn, *a);
return ret;
}
static int tcf_vlan_dump(struct sk_buff *skb, struct tc_action *a,
int bind, int ref)
{
unsigned char *b = skb_tail_pointer(skb);
struct tcf_vlan *v = to_vlan(a);
struct tc_vlan opt = {
.index = v->tcf_index,
.refcnt = v->tcf_refcnt - ref,
.bindcnt = v->tcf_bindcnt - bind,
.action = v->tcf_action,
.v_action = v->tcfv_action,
};
struct tcf_t t;
if (nla_put(skb, TCA_VLAN_PARMS, sizeof(opt), &opt))
goto nla_put_failure;
if ((v->tcfv_action == TCA_VLAN_ACT_PUSH ||
v->tcfv_action == TCA_VLAN_ACT_MODIFY) &&
(nla_put_u16(skb, TCA_VLAN_PUSH_VLAN_ID, v->tcfv_push_vid) ||
nla_put_be16(skb, TCA_VLAN_PUSH_VLAN_PROTOCOL,
v->tcfv_push_proto) ||
(nla_put_u8(skb, TCA_VLAN_PUSH_VLAN_PRIORITY,
v->tcfv_push_prio))))
goto nla_put_failure;
tcf_tm_dump(&t, &v->tcf_tm);
if (nla_put_64bit(skb, TCA_VLAN_TM, sizeof(t), &t, TCA_VLAN_PAD))
goto nla_put_failure;
return skb->len;
nla_put_failure:
nlmsg_trim(skb, b);
return -1;
}
static int tcf_vlan_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, vlan_net_id);
return tcf_generic_walker(tn, skb, cb, type, ops);
}
static int tcf_vlan_search(struct net *net, struct tc_action **a, u32 index)
{
struct tc_action_net *tn = net_generic(net, vlan_net_id);
return tcf_hash_search(tn, a, index);
}
static struct tc_action_ops act_vlan_ops = {
.kind = "vlan",
.type = TCA_ACT_VLAN,
.owner = THIS_MODULE,
.act = tcf_vlan,
.dump = tcf_vlan_dump,
.init = tcf_vlan_init,
.walk = tcf_vlan_walker,
.lookup = tcf_vlan_search,
.size = sizeof(struct tcf_vlan),
};
static __net_init int vlan_init_net(struct net *net)
{
struct tc_action_net *tn = net_generic(net, vlan_net_id);
return tc_action_net_init(tn, &act_vlan_ops, VLAN_TAB_MASK);
}
static void __net_exit vlan_exit_net(struct net *net)
{
struct tc_action_net *tn = net_generic(net, vlan_net_id);
tc_action_net_exit(tn);
}
static struct pernet_operations vlan_net_ops = {
.init = vlan_init_net,
.exit = vlan_exit_net,
.id = &vlan_net_id,
.size = sizeof(struct tc_action_net),
};
static int __init vlan_init_module(void)
{
return tcf_register_action(&act_vlan_ops, &vlan_net_ops);
}
static void __exit vlan_cleanup_module(void)
{
tcf_unregister_action(&act_vlan_ops, &vlan_net_ops);
}
module_init(vlan_init_module);
module_exit(vlan_cleanup_module);
MODULE_AUTHOR("Jiri Pirko <jiri@resnulli.us>");
MODULE_DESCRIPTION("vlan manipulation actions");
MODULE_LICENSE("GPL v2");