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netfilter: Create and use nf_hook_state.
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Instead of passing a large number of arguments down into the nf_hook()
entry points, create a structure which carries this state down through
the hook processing layers.

This makes is so that if we want to change the types or signatures of
any of these pieces of state, there are less places that need to be
changed.

Signed-off-by: David S. Miller <davem@davemloft.net>
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David S. Miller committed Apr 4, 2015
1 parent b81b7be commit cfdfab3
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Showing 4 changed files with 59 additions and 50 deletions.
28 changes: 23 additions & 5 deletions include/linux/netfilter.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -44,6 +44,16 @@ int netfilter_init(void);
struct sk_buff;

struct nf_hook_ops;

struct nf_hook_state {
unsigned int hook;
int thresh;
u_int8_t pf;
struct net_device *in;
struct net_device *out;
int (*okfn)(struct sk_buff *);
};

typedef unsigned int nf_hookfn(const struct nf_hook_ops *ops,
struct sk_buff *skb,
const struct net_device *in,
Expand Down Expand Up @@ -118,9 +128,7 @@ static inline bool nf_hooks_active(u_int8_t pf, unsigned int hook)
}
#endif

int nf_hook_slow(u_int8_t pf, unsigned int hook, struct sk_buff *skb,
struct net_device *indev, struct net_device *outdev,
int (*okfn)(struct sk_buff *), int thresh);
int nf_hook_slow(struct sk_buff *skb, struct nf_hook_state *state);

/**
* nf_hook_thresh - call a netfilter hook
Expand All @@ -135,8 +143,18 @@ static inline int nf_hook_thresh(u_int8_t pf, unsigned int hook,
struct net_device *outdev,
int (*okfn)(struct sk_buff *), int thresh)
{
if (nf_hooks_active(pf, hook))
return nf_hook_slow(pf, hook, skb, indev, outdev, okfn, thresh);
if (nf_hooks_active(pf, hook)) {
struct nf_hook_state state = {
.hook = hook,
.thresh = thresh,
.pf = pf,
.in = indev,
.out = outdev,
.okfn = okfn
};

return nf_hook_slow(skb, &state);
}
return 1;
}

Expand Down
32 changes: 13 additions & 19 deletions net/netfilter/core.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -120,12 +120,8 @@ EXPORT_SYMBOL(nf_unregister_hooks);

unsigned int nf_iterate(struct list_head *head,
struct sk_buff *skb,
unsigned int hook,
const struct net_device *indev,
const struct net_device *outdev,
struct nf_hook_ops **elemp,
int (*okfn)(struct sk_buff *),
int hook_thresh)
struct nf_hook_state *state,
struct nf_hook_ops **elemp)
{
unsigned int verdict;

Expand All @@ -134,19 +130,20 @@ unsigned int nf_iterate(struct list_head *head,
* function because of risk of continuing from deleted element.
*/
list_for_each_entry_continue_rcu((*elemp), head, list) {
if (hook_thresh > (*elemp)->priority)
if (state->thresh > (*elemp)->priority)
continue;

/* Optimization: we don't need to hold module
reference here, since function can't sleep. --RR */
repeat:
verdict = (*elemp)->hook(*elemp, skb, indev, outdev, okfn);
verdict = (*elemp)->hook(*elemp, skb, state->in, state->out,
state->okfn);
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, hook);
(*elemp)->hook, state->hook);
continue;
}
#endif
Expand All @@ -161,11 +158,7 @@ unsigned int nf_iterate(struct list_head *head,

/* Returns 1 if okfn() needs to be executed by the caller,
* -EPERM for NF_DROP, 0 otherwise. */
int nf_hook_slow(u_int8_t pf, unsigned int hook, struct sk_buff *skb,
struct net_device *indev,
struct net_device *outdev,
int (*okfn)(struct sk_buff *),
int hook_thresh)
int nf_hook_slow(struct sk_buff *skb, struct nf_hook_state *state)
{
struct nf_hook_ops *elem;
unsigned int verdict;
Expand All @@ -174,10 +167,11 @@ int nf_hook_slow(u_int8_t pf, unsigned int hook, struct sk_buff *skb,
/* We may already have this, but read-locks nest anyway */
rcu_read_lock();

elem = list_entry_rcu(&nf_hooks[pf][hook], struct nf_hook_ops, list);
elem = list_entry_rcu(&nf_hooks[state->pf][state->hook],
struct nf_hook_ops, list);
next_hook:
verdict = nf_iterate(&nf_hooks[pf][hook], skb, hook, indev,
outdev, &elem, okfn, hook_thresh);
verdict = nf_iterate(&nf_hooks[state->pf][state->hook], skb, state,
&elem);
if (verdict == NF_ACCEPT || verdict == NF_STOP) {
ret = 1;
} else if ((verdict & NF_VERDICT_MASK) == NF_DROP) {
Expand All @@ -186,8 +180,8 @@ int nf_hook_slow(u_int8_t pf, unsigned int hook, struct sk_buff *skb,
if (ret == 0)
ret = -EPERM;
} else if ((verdict & NF_VERDICT_MASK) == NF_QUEUE) {
int err = nf_queue(skb, elem, pf, hook, indev, outdev, okfn,
verdict >> NF_VERDICT_QBITS);
int err = nf_queue(skb, elem, state,
verdict >> NF_VERDICT_QBITS);
if (err < 0) {
if (err == -ECANCELED)
goto next_hook;
Expand Down
11 changes: 3 additions & 8 deletions net/netfilter/nf_internals.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -14,16 +14,11 @@

/* core.c */
unsigned int nf_iterate(struct list_head *head, struct sk_buff *skb,
unsigned int hook, const struct net_device *indev,
const struct net_device *outdev,
struct nf_hook_ops **elemp,
int (*okfn)(struct sk_buff *), int hook_thresh);
struct nf_hook_state *state, struct nf_hook_ops **elemp);

/* nf_queue.c */
int nf_queue(struct sk_buff *skb, struct nf_hook_ops *elem, u_int8_t pf,
unsigned int hook, struct net_device *indev,
struct net_device *outdev, int (*okfn)(struct sk_buff *),
unsigned int queuenum);
int nf_queue(struct sk_buff *skb, struct nf_hook_ops *elem,
struct nf_hook_state *state, unsigned int queuenum);
int __init netfilter_queue_init(void);

/* nf_log.c */
Expand Down
38 changes: 20 additions & 18 deletions net/netfilter/nf_queue.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -100,12 +100,9 @@ EXPORT_SYMBOL_GPL(nf_queue_entry_get_refs);
* through nf_reinject().
*/
int nf_queue(struct sk_buff *skb,
struct nf_hook_ops *elem,
u_int8_t pf, unsigned int hook,
struct net_device *indev,
struct net_device *outdev,
int (*okfn)(struct sk_buff *),
unsigned int queuenum)
struct nf_hook_ops *elem,
struct nf_hook_state *state,
unsigned int queuenum)
{
int status = -ENOENT;
struct nf_queue_entry *entry = NULL;
Expand All @@ -121,7 +118,7 @@ int nf_queue(struct sk_buff *skb,
goto err_unlock;
}

afinfo = nf_get_afinfo(pf);
afinfo = nf_get_afinfo(state->pf);
if (!afinfo)
goto err_unlock;

Expand All @@ -134,11 +131,11 @@ int nf_queue(struct sk_buff *skb,
*entry = (struct nf_queue_entry) {
.skb = skb,
.elem = elem,
.pf = pf,
.hook = hook,
.indev = indev,
.outdev = outdev,
.okfn = okfn,
.pf = state->pf,
.hook = state->hook,
.indev = state->in,
.outdev = state->out,
.okfn = state->okfn,
.size = sizeof(*entry) + afinfo->route_key_size,
};

Expand Down Expand Up @@ -171,6 +168,7 @@ void nf_reinject(struct nf_queue_entry *entry, unsigned int verdict)
struct sk_buff *skb = entry->skb;
struct nf_hook_ops *elem = entry->elem;
const struct nf_afinfo *afinfo;
struct nf_hook_state state;
int err;

rcu_read_lock();
Expand All @@ -189,12 +187,17 @@ void nf_reinject(struct nf_queue_entry *entry, unsigned int verdict)
verdict = NF_DROP;
}

state.hook = entry->hook;
state.thresh = INT_MIN;
state.pf = entry->pf;
state.in = entry->indev;
state.out = entry->outdev;
state.okfn = entry->okfn;

if (verdict == NF_ACCEPT) {
next_hook:
verdict = nf_iterate(&nf_hooks[entry->pf][entry->hook],
skb, entry->hook,
entry->indev, entry->outdev, &elem,
entry->okfn, INT_MIN);
skb, &state, &elem);
}

switch (verdict & NF_VERDICT_MASK) {
Expand All @@ -205,9 +208,8 @@ void nf_reinject(struct nf_queue_entry *entry, unsigned int verdict)
local_bh_enable();
break;
case NF_QUEUE:
err = nf_queue(skb, elem, entry->pf, entry->hook,
entry->indev, entry->outdev, entry->okfn,
verdict >> NF_VERDICT_QBITS);
err = nf_queue(skb, elem, &state,
verdict >> NF_VERDICT_QBITS);
if (err < 0) {
if (err == -ECANCELED)
goto next_hook;
Expand Down

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