Minki/linux
1
0
Fork 1
mirror of https://github.com/torvalds/linux.git synced 2024-11-11 14:42:24 +00:00
Code Issues Packages Projects Releases Wiki Activity

netfilter: replace list_head with single linked list

Browse Source 
The netfilter hook list never uses the prev pointer, and so can be trimmed to
be a simple singly-linked list.

In addition to having a more light weight structure for hook traversal,
struct net becomes 5568 bytes (down from 6400) and struct net_device becomes
2176 bytes (down from 2240).

Signed-off-by: Aaron Conole <aconole@bytheb.org>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This commit is contained in:
Aaron Conole 2016-09-21 11:35:07 -04:00 committed by Pablo Neira Ayuso
parent 54f17bbc52
commit e3b37f11e6
10 changed files with 169 additions and 118 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
include/linux/netdevice.h
View File

@ -1783,7 +1783,7 @@ struct net_device {
#endif
struct netdev_queue __rcu *ingress_queue;
#ifdef CONFIG_NETFILTER_INGRESS
struct list_head nf_hooks_ingress;
struct nf_hook_entry __rcu *nf_hooks_ingress;
#endif
unsigned char broadcast[MAX_ADDR_LEN];

63
include/linux/netfilter.h
View File

@ -55,12 +55,34 @@ struct nf_hook_state {
struct net_device *out;
struct sock *sk;
struct net *net;
struct list_head *hook_list;
struct nf_hook_entry __rcu *hook_entries;
int (*okfn)(struct net *, struct sock *, struct sk_buff *);
};
typedef unsigned int nf_hookfn(void *priv,
struct sk_buff *skb,
const struct nf_hook_state *state);
struct nf_hook_ops {
struct list_head list;
/* User fills in from here down. */
nf_hookfn *hook;
struct net_device *dev;
void *priv;
u_int8_t pf;
unsigned int hooknum;
/* Hooks are ordered in ascending priority. */
int priority;
};
struct nf_hook_entry {
struct nf_hook_entry __rcu *next;
struct nf_hook_ops ops;
const struct nf_hook_ops *orig_ops;
};
static inline void nf_hook_state_init(struct nf_hook_state *p,
struct list_head *hook_list,
struct nf_hook_entry *hook_entry,
unsigned int hook,
int thresh, u_int8_t pf,
struct net_device *indev,
@ -76,26 +98,11 @@ static inline void nf_hook_state_init(struct nf_hook_state *p,
p->out = outdev;
p->sk = sk;
p->net = net;
p->hook_list = hook_list;
RCU_INIT_POINTER(p->hook_entries, hook_entry);
p->okfn = okfn;
}
typedef unsigned int nf_hookfn(void *priv,
struct sk_buff *skb,
const struct nf_hook_state *state);
struct nf_hook_ops {
struct list_head list;
/* User fills in from here down. */
nf_hookfn *hook;
struct net_device *dev;
void *priv;
u_int8_t pf;
unsigned int hooknum;
/* Hooks are ordered in ascending priority. */
int priority;
};
struct nf_sockopt_ops {
struct list_head list;
@ -161,7 +168,8 @@ static inline int nf_hook_thresh(u_int8_t pf, unsigned int hook,
int (*okfn)(struct net *, struct sock *, struct sk_buff *),
int thresh)
{
struct list_head *hook_list;
struct nf_hook_entry *hook_head;
int ret = 1;
#ifdef HAVE_JUMP_LABEL
if (__builtin_constant_p(pf) &&
@ -170,22 +178,19 @@ static inline int nf_hook_thresh(u_int8_t pf, unsigned int hook,
return 1;
#endif
hook_list = &net->nf.hooks[pf][hook];
if (!list_empty(hook_list)) {
rcu_read_lock();
hook_head = rcu_dereference(net->nf.hooks[pf][hook]);
if (hook_head) {
struct nf_hook_state state;
int ret;
/* We may already have this, but read-locks nest anyway */
rcu_read_lock();
nf_hook_state_init(&state, hook_list, hook, thresh,
nf_hook_state_init(&state, hook_head, hook, thresh,
pf, indev, outdev, sk, net, okfn);
ret = nf_hook_slow(skb, &state);
rcu_read_unlock();
return ret;
}
return 1;
rcu_read_unlock();
return ret;
}
static inline int nf_hook(u_int8_t pf, unsigned int hook, struct net *net,

17
include/linux/netfilter_ingress.h
View File

@ -11,23 +11,30 @@ static inline bool nf_hook_ingress_active(const struct sk_buff *skb)
if (!static_key_false(&nf_hooks_needed[NFPROTO_NETDEV][NF_NETDEV_INGRESS]))
return false;
#endif
return !list_empty(&skb->dev->nf_hooks_ingress);
return rcu_access_pointer(skb->dev->nf_hooks_ingress);
}
/* caller must hold rcu_read_lock */
static inline int nf_hook_ingress(struct sk_buff *skb)
{
struct nf_hook_entry *e = rcu_dereference(skb->dev->nf_hooks_ingress);
struct nf_hook_state state;
nf_hook_state_init(&state, &skb->dev->nf_hooks_ingress,
NF_NETDEV_INGRESS, INT_MIN, NFPROTO_NETDEV,
skb->dev, NULL, NULL, dev_net(skb->dev), NULL);
/* Must recheck the ingress hook head, in the event it became NULL
* after the check in nf_hook_ingress_active evaluated to true.
*/
if (unlikely(!e))
return 0;
nf_hook_state_init(&state, e, NF_NETDEV_INGRESS, INT_MIN,
NFPROTO_NETDEV, skb->dev, NULL, NULL,
dev_net(skb->dev), NULL);
return nf_hook_slow(skb, &state);
}
static inline void nf_hook_ingress_init(struct net_device *dev)
{
INIT_LIST_HEAD(&dev->nf_hooks_ingress);
RCU_INIT_POINTER(dev->nf_hooks_ingress, NULL);
}
#else /* CONFIG_NETFILTER_INGRESS */
static inline int nf_hook_ingress_active(struct sk_buff *skb)

3
include/net/netfilter/nf_queue.h
View File

@ -11,7 +11,6 @@ struct nf_queue_entry {
struct sk_buff *skb;
unsigned int id;
struct nf_hook_ops *elem;
struct nf_hook_state state;
u16 size; /* sizeof(entry) + saved route keys */
@ -25,7 +24,7 @@ struct nf_queue_handler {
int (*outfn)(struct nf_queue_entry *entry,
unsigned int queuenum);
void (*nf_hook_drop)(struct net *net,
struct nf_hook_ops *ops);
const struct nf_hook_entry *hooks);
};
void nf_register_queue_handler(struct net *net, const struct nf_queue_handler *qh);

2
include/net/netns/netfilter.h
View File

@ -16,6 +16,6 @@ struct netns_nf {
#ifdef CONFIG_SYSCTL
struct ctl_table_header *nf_log_dir_header;
#endif
struct list_head hooks[NFPROTO_NUMPROTO][NF_MAX_HOOKS];
struct nf_hook_entry __rcu *hooks[NFPROTO_NUMPROTO][NF_MAX_HOOKS];
};
#endif

19
net/bridge/br_netfilter_hooks.c
View File

@ -1002,28 +1002,21 @@ int br_nf_hook_thresh(unsigned int hook, struct net *net,
int (*okfn)(struct net *, struct sock *,
struct sk_buff *))
{
struct nf_hook_ops *elem;
struct nf_hook_entry *elem;
struct nf_hook_state state;
struct list_head *head;
int ret;
head = &net->nf.hooks[NFPROTO_BRIDGE][hook];
elem = rcu_dereference(net->nf.hooks[NFPROTO_BRIDGE][hook]);
list_for_each_entry_rcu(elem, head, list) {
struct nf_hook_ops *next;
while (elem && (elem->ops.priority <= NF_BR_PRI_BRNF))
elem = rcu_dereference(elem->next);
next = list_entry_rcu(list_next_rcu(&elem->list),
struct nf_hook_ops, list);
if (next->priority <= NF_BR_PRI_BRNF)
continue;
}
if (&elem->list == head)
if (!elem)
return okfn(net, sk, skb);
/* We may already have this, but read-locks nest anyway */
rcu_read_lock();
nf_hook_state_init(&state, head, hook, NF_BR_PRI_BRNF + 1,
nf_hook_state_init(&state, elem, hook, NF_BR_PRI_BRNF + 1,
NFPROTO_BRIDGE, indev, outdev, sk, net, okfn);
ret = nf_hook_slow(skb, &state);

145
net/netfilter/core.c
View File

@ -22,6 +22,7 @@
#include <linux/proc_fs.h>
#include <linux/mutex.h>
#include <linux/slab.h>
#include <linux/rcupdate.h>
#include <net/net_namespace.h>
#include <net/sock.h>
@ -61,33 +62,50 @@ EXPORT_SYMBOL(nf_hooks_needed);
#endif
static DEFINE_MUTEX(nf_hook_mutex);
#define nf_entry_dereference(e) \
rcu_dereference_protected(e, lockdep_is_held(&nf_hook_mutex))
static struct list_head *nf_find_hook_list(struct net *net,
const struct nf_hook_ops *reg)
static struct nf_hook_entry *nf_hook_entry_head(struct net *net,
const struct nf_hook_ops *reg)
{
struct list_head *hook_list = NULL;
struct nf_hook_entry *hook_head = NULL;
if (reg->pf != NFPROTO_NETDEV)
hook_list = &net->nf.hooks[reg->pf][reg->hooknum];
hook_head = nf_entry_dereference(net->nf.hooks[reg->pf]
[reg->hooknum]);
else if (reg->hooknum == NF_NETDEV_INGRESS) {
#ifdef CONFIG_NETFILTER_INGRESS
if (reg->dev && dev_net(reg->dev) == net)
hook_list = &reg->dev->nf_hooks_ingress;
hook_head =
nf_entry_dereference(
reg->dev->nf_hooks_ingress);
#endif
}
return hook_list;
return hook_head;
}
struct nf_hook_entry {
const struct nf_hook_ops *orig_ops;
struct nf_hook_ops ops;
};
/* must hold nf_hook_mutex */
static void nf_set_hooks_head(struct net *net, const struct nf_hook_ops *reg,
struct nf_hook_entry *entry)
{
switch (reg->pf) {
case NFPROTO_NETDEV:
/* We already checked in nf_register_net_hook() that this is
* used from ingress.
*/
rcu_assign_pointer(reg->dev->nf_hooks_ingress, entry);
break;
default:
rcu_assign_pointer(net->nf.hooks[reg->pf][reg->hooknum],
entry);
break;
}
}
int nf_register_net_hook(struct net *net, const struct nf_hook_ops *reg)
{
struct list_head *hook_list;
struct nf_hook_entry *hooks_entry;
struct nf_hook_entry *entry;
struct nf_hook_ops *elem;
if (reg->pf == NFPROTO_NETDEV &&
(reg->hooknum != NF_NETDEV_INGRESS ||
@ -100,19 +118,30 @@ int nf_register_net_hook(struct net *net, const struct nf_hook_ops *reg)
entry->orig_ops = reg;
entry->ops = *reg;
hook_list = nf_find_hook_list(net, reg);
if (!hook_list) {
kfree(entry);
return -ENOENT;
}
entry->next = NULL;
mutex_lock(&nf_hook_mutex);
list_for_each_entry(elem, hook_list, list) {
if (reg->priority < elem->priority)
break;
hooks_entry = nf_hook_entry_head(net, reg);
if (hooks_entry && hooks_entry->orig_ops->priority > reg->priority) {
/* This is the case where we need to insert at the head */
entry->next = hooks_entry;
hooks_entry = NULL;
}
list_add_rcu(&entry->ops.list, elem->list.prev);
while (hooks_entry &&
reg->priority >= hooks_entry->orig_ops->priority &&
nf_entry_dereference(hooks_entry->next)) {
hooks_entry = nf_entry_dereference(hooks_entry->next);
}
if (hooks_entry) {
entry->next = nf_entry_dereference(hooks_entry->next);
rcu_assign_pointer(hooks_entry->next, entry);
} else {
nf_set_hooks_head(net, reg, entry);
}
mutex_unlock(&nf_hook_mutex);
#ifdef CONFIG_NETFILTER_INGRESS
if (reg->pf == NFPROTO_NETDEV && reg->hooknum == NF_NETDEV_INGRESS)
@ -127,24 +156,33 @@ EXPORT_SYMBOL(nf_register_net_hook);
void nf_unregister_net_hook(struct net *net, const struct nf_hook_ops *reg)
{
struct list_head *hook_list;
struct nf_hook_entry *entry;
struct nf_hook_ops *elem;
hook_list = nf_find_hook_list(net, reg);
if (!hook_list)
return;
struct nf_hook_entry *hooks_entry;
mutex_lock(&nf_hook_mutex);
list_for_each_entry(elem, hook_list, list) {
entry = container_of(elem, struct nf_hook_entry, ops);
if (entry->orig_ops == reg) {
list_del_rcu(&entry->ops.list);
break;
}
hooks_entry = nf_hook_entry_head(net, reg);
if (hooks_entry->orig_ops == reg) {
nf_set_hooks_head(net, reg,
nf_entry_dereference(hooks_entry->next));
goto unlock;
}
while (hooks_entry && nf_entry_dereference(hooks_entry->next)) {
struct nf_hook_entry *next =
nf_entry_dereference(hooks_entry->next);
struct nf_hook_entry *nnext;
if (next->orig_ops != reg) {
hooks_entry = next;
continue;
}
nnext = nf_entry_dereference(next->next);
rcu_assign_pointer(hooks_entry->next, nnext);
hooks_entry = next;
break;
}
unlock:
mutex_unlock(&nf_hook_mutex);
if (&elem->list == hook_list) {
if (!hooks_entry) {
WARN(1, "nf_unregister_net_hook: hook not found!\n");
return;
}
@ -156,10 +194,10 @@ void nf_unregister_net_hook(struct net *net, const struct nf_hook_ops *reg)
static_key_slow_dec(&nf_hooks_needed[reg->pf][reg->hooknum]);
#endif
synchronize_net();
nf_queue_nf_hook_drop(net, &entry->ops);
nf_queue_nf_hook_drop(net, hooks_entry);
/* other cpu might still process nfqueue verdict that used reg */
synchronize_net();
kfree(entry);
kfree(hooks_entry);
}
EXPORT_SYMBOL(nf_unregister_net_hook);
@ -258,10 +296,9 @@ void nf_unregister_hooks(struct nf_hook_ops *reg, unsigned int n)
}
EXPORT_SYMBOL(nf_unregister_hooks);
unsigned int nf_iterate(struct list_head *head,
struct sk_buff *skb,
unsigned int nf_iterate(struct sk_buff *skb,
struct nf_hook_state *state,
struct nf_hook_ops **elemp)
struct nf_hook_entry **entryp)
{
unsigned int verdict;
@ -269,20 +306,23 @@ unsigned int nf_iterate(struct list_head *head,
* The caller must not block between calls to this
* function because of risk of continuing from deleted element.
*/
list_for_each_entry_continue_rcu((*elemp), head, list) {
if (state->thresh > (*elemp)->priority)
while (*entryp) {
if (state->thresh > (*entryp)->ops.priority) {
*entryp = rcu_dereference((*entryp)->next);
continue;
}
/* Optimization: we don't need to hold module
reference here, since function can't sleep. --RR */
repeat:
verdict = (*elemp)->hook((*elemp)->priv, skb, state);
verdict = (*entryp)->ops.hook((*entryp)->ops.priv, skb, state);
if (verdict != NF_ACCEPT) {
#ifdef CONFIG_NETFILTER_DEBUG
if (unlikely((verdict & NF_VERDICT_MASK)
> NF_MAX_VERDICT)) {
NFDEBUG("Evil return from %p(%u).\n",
(*elemp)->hook, state->hook);
(*entryp)->ops.hook, state->hook);
*entryp = rcu_dereference((*entryp)->next);
continue;
}
#endif
@ -290,6 +330,7 @@ repeat:
return verdict;
goto repeat;
}
*entryp = rcu_dereference((*entryp)->next);
}
return NF_ACCEPT;
}
@ -299,13 +340,13 @@ repeat:
* -EPERM for NF_DROP, 0 otherwise. Caller must hold rcu_read_lock. */
int nf_hook_slow(struct sk_buff *skb, struct nf_hook_state *state)
{
struct nf_hook_ops *elem;
struct nf_hook_entry *entry;
unsigned int verdict;
int ret = 0;
elem = list_entry_rcu(state->hook_list, struct nf_hook_ops, list);
entry = rcu_dereference(state->hook_entries);
next_hook:
verdict = nf_iterate(state->hook_list, skb, state, &elem);
verdict = nf_iterate(skb, state, &entry);
if (verdict == NF_ACCEPT || verdict == NF_STOP) {
ret = 1;
} else if ((verdict & NF_VERDICT_MASK) == NF_DROP) {
@ -314,8 +355,10 @@ next_hook:
if (ret == 0)
ret = -EPERM;
} else if ((verdict & NF_VERDICT_MASK) == NF_QUEUE) {
int err = nf_queue(skb, elem, state,
verdict >> NF_VERDICT_QBITS);
int err;
RCU_INIT_POINTER(state->hook_entries, entry);
err = nf_queue(skb, state, verdict >> NF_VERDICT_QBITS);
if (err < 0) {
if (err == -ESRCH &&
(verdict & NF_VERDICT_FLAG_QUEUE_BYPASS))
@ -442,7 +485,7 @@ static int __net_init netfilter_net_init(struct net *net)
for (i = 0; i < ARRAY_SIZE(net->nf.hooks); i++) {
for (h = 0; h < NF_MAX_HOOKS; h++)
INIT_LIST_HEAD(&net->nf.hooks[i][h]);
RCU_INIT_POINTER(net->nf.hooks[i][h], NULL);
}
#ifdef CONFIG_PROC_FS

10
net/netfilter/nf_internals.h
View File

@ -13,13 +13,13 @@
/* core.c */
unsigned int nf_iterate(struct list_head *head, struct sk_buff *skb,
struct nf_hook_state *state, struct nf_hook_ops **elemp);
unsigned int nf_iterate(struct sk_buff *skb, struct nf_hook_state *state,
struct nf_hook_entry **entryp);
/* nf_queue.c */
int nf_queue(struct sk_buff *skb, struct nf_hook_ops *elem,
struct nf_hook_state *state, unsigned int queuenum);
void nf_queue_nf_hook_drop(struct net *net, struct nf_hook_ops *ops);
int nf_queue(struct sk_buff *skb, struct nf_hook_state *state,
unsigned int queuenum);
void nf_queue_nf_hook_drop(struct net *net, const struct nf_hook_entry *entry);
int __init netfilter_queue_init(void);
/* nf_log.c */

18
net/netfilter/nf_queue.c
View File

@ -96,14 +96,14 @@ void nf_queue_entry_get_refs(struct nf_queue_entry *entry)
}
EXPORT_SYMBOL_GPL(nf_queue_entry_get_refs);
void nf_queue_nf_hook_drop(struct net *net, struct nf_hook_ops *ops)
void nf_queue_nf_hook_drop(struct net *net, const struct nf_hook_entry *entry)
{
const struct nf_queue_handler *qh;
rcu_read_lock();
qh = rcu_dereference(net->nf.queue_handler);
if (qh)
qh->nf_hook_drop(net, ops);
qh->nf_hook_drop(net, entry);
rcu_read_unlock();
}
@ -112,7 +112,6 @@ void nf_queue_nf_hook_drop(struct net *net, struct nf_hook_ops *ops)
* through nf_reinject().
*/
int nf_queue(struct sk_buff *skb,
struct nf_hook_ops *elem,
struct nf_hook_state *state,
unsigned int queuenum)
{
@ -141,7 +140,6 @@ int nf_queue(struct sk_buff *skb,
*entry = (struct nf_queue_entry) {
.skb = skb,
.elem = elem,
.state = *state,
.size = sizeof(*entry) + afinfo->route_key_size,
};
@ -165,11 +163,15 @@ err:
void nf_reinject(struct nf_queue_entry *entry, unsigned int verdict)
{
struct nf_hook_entry *hook_entry;
struct sk_buff *skb = entry->skb;
struct nf_hook_ops *elem = entry->elem;
const struct nf_afinfo *afinfo;
struct nf_hook_ops *elem;
int err;
hook_entry = rcu_dereference(entry->state.hook_entries);
elem = &hook_entry->ops;
nf_queue_entry_release_refs(entry);
/* Continue traversal iff userspace said ok... */
@ -186,8 +188,7 @@ void nf_reinject(struct nf_queue_entry *entry, unsigned int verdict)
if (verdict == NF_ACCEPT) {
next_hook:
verdict = nf_iterate(entry->state.hook_list,
skb, &entry->state, &elem);
verdict = nf_iterate(skb, &entry->state, &hook_entry);
}
switch (verdict & NF_VERDICT_MASK) {
@ -198,7 +199,8 @@ void nf_reinject(struct nf_queue_entry *entry, unsigned int verdict)
local_bh_enable();
break;
case NF_QUEUE:
err = nf_queue(skb, elem, &entry->state,
RCU_INIT_POINTER(entry->state.hook_entries, hook_entry);
err = nf_queue(skb, &entry->state,
verdict >> NF_VERDICT_QBITS);
if (err < 0) {
if (err == -ESRCH &&

8
net/netfilter/nfnetlink_queue.c
View File

@ -917,12 +917,14 @@ static struct notifier_block nfqnl_dev_notifier = {
.notifier_call = nfqnl_rcv_dev_event,
};
static int nf_hook_cmp(struct nf_queue_entry *entry, unsigned long ops_ptr)
static int nf_hook_cmp(struct nf_queue_entry *entry, unsigned long entry_ptr)
{
return entry->elem == (struct nf_hook_ops *)ops_ptr;
return rcu_access_pointer(entry->state.hook_entries) ==
(struct nf_hook_entry *)entry_ptr;
}
static void nfqnl_nf_hook_drop(struct net *net, struct nf_hook_ops *hook)
static void nfqnl_nf_hook_drop(struct net *net,
const struct nf_hook_entry *hook)
{
struct nfnl_queue_net *q = nfnl_queue_pernet(net);
int i;