@@ -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];
@@ -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,
@@ -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)
@@ -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);
@@ -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
@@ -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);
@@ -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 = ®->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;
+ entry->next = NULL;
+
+ mutex_lock(&nf_hook_mutex);
+ hooks_entry = nf_hook_entry_head(net, reg);
- hook_list = nf_find_hook_list(net, reg);
- if (!hook_list) {
- kfree(entry);
- return -ENOENT;
+ 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;
}
- mutex_lock(&nf_hook_mutex);
- list_for_each_entry(elem, hook_list, list) {
- if (reg->priority < elem->priority)
- break;
+ 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);
}
- list_add_rcu(&entry->ops.list, elem->list.prev);
+
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
@@ -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 */
@@ -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 &&
@@ -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;