netfilter: Create and use nf_hook_state.

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 <[e-mail]>

include/linux/netfilter.h

···
 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,
···
 }
 #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
···
 				 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;
 }
 

net/netfilter/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)
 {
 	unsigned int verdict;
 
···
 	 * 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
···
 
 /* 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;
···
 	/* 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) {
···
 		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;

net/netfilter/nf_internals.h

···
 
 /* 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 */

net/netfilter/nf_queue.c

···
  * 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;
···
 		goto err_unlock;
 	}
 
-	afinfo = nf_get_afinfo(pf);
+	afinfo = nf_get_afinfo(state->pf);
 	if (!afinfo)
 		goto err_unlock;
 
···
 	*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,
 	};
 
···
 	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();
···
 			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) {
···
 		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;