/* * Rusty Russell (C)2000 -- This code is GPL. * Patrick McHardy (c) 2006-2012 */ #include <linux/kernel.h>#include <linux/slab.h>#include <linux/init.h>#include <linux/module.h>#include <linux/proc_fs.h>#include <linux/skbuff.h>#include <linux/netfilter.h>#include <linux/netfilter_bridge.h>#include <linux/seq_file.h>#include <linux/rcupdate.h>#include <net/protocol.h>#include <net/netfilter/nf_queue.h>#include <net/dst.h> #include "nf_internals.h" /* * Hook for nfnetlink_queue to register its queue handler. * We do this so that most of the NFQUEUE code can be modular. * * Once the queue is registered it must reinject all packets it * receives, no matter what. */ /* return EBUSY when somebody else is registered, return EEXIST if the * same handler is registered, return 0 in case of success. */void nf_register_queue_handler(struct net *net, const struct nf_queue_handler *qh){	/* should never happen, we only have one queueing backend in kernel */	WARN_ON(rcu_access_pointer(net->nf.queue_handler));	rcu_assign_pointer(net->nf.queue_handler, qh);}EXPORT_SYMBOL(nf_register_queue_handler); /* The caller must flush their queue before this */void nf_unregister_queue_handler(struct net *net){	RCU_INIT_POINTER(net->nf.queue_handler, NULL);}EXPORT_SYMBOL(nf_unregister_queue_handler); void nf_queue_entry_release_refs(struct nf_queue_entry *entry){	struct nf_hook_state *state = &entry->state; 	/* Release those devices we held, or Alexey will kill me. */	if (state->in)		dev_put(state->in);	if (state->out)		dev_put(state->out);	if (state->sk)		sock_put(state->sk);#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)	if (entry->skb->nf_bridge) {		struct net_device *physdev; 		physdev = nf_bridge_get_physindev(entry->skb);		if (physdev)			dev_put(physdev);		physdev = nf_bridge_get_physoutdev(entry->skb);		if (physdev)			dev_put(physdev);	}#endif}EXPORT_SYMBOL_GPL(nf_queue_entry_release_refs); /* Bump dev refs so they don't vanish while packet is out */void nf_queue_entry_get_refs(struct nf_queue_entry *entry){	struct nf_hook_state *state = &entry->state; 	if (state->in)		dev_hold(state->in);	if (state->out)		dev_hold(state->out);	if (state->sk)		sock_hold(state->sk);#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)	if (entry->skb->nf_bridge) {		struct net_device *physdev; 		physdev = nf_bridge_get_physindev(entry->skb);		if (physdev)			dev_hold(physdev);		physdev = nf_bridge_get_physoutdev(entry->skb);		if (physdev)			dev_hold(physdev);	}#endif}EXPORT_SYMBOL_GPL(nf_queue_entry_get_refs); unsigned int nf_queue_nf_hook_drop(struct net *net){	const struct nf_queue_handler *qh;	unsigned int count = 0; 	rcu_read_lock();	qh = rcu_dereference(net->nf.queue_handler);	if (qh)		count = qh->nf_hook_drop(net);	rcu_read_unlock(); 	return count;} static int __nf_queue(struct sk_buff *skb, const struct nf_hook_state *state,		      struct nf_hook_entry *hook_entry, unsigned int queuenum){	int status = -ENOENT;	struct nf_queue_entry *entry = NULL;	const struct nf_afinfo *afinfo;	const struct nf_queue_handler *qh;	struct net *net = state->net; 	/* QUEUE == DROP if no one is waiting, to be safe. */	qh = rcu_dereference(net->nf.queue_handler);	if (!qh) {		status = -ESRCH;		goto err;	} 	afinfo = nf_get_afinfo(state->pf);	if (!afinfo)		goto err; 	entry = kmalloc(sizeof(*entry) + afinfo->route_key_size, GFP_ATOMIC);	if (!entry) {		status = -ENOMEM;		goto err;	} 	*entry = (struct nf_queue_entry) {		.skb	= skb,		.state	= *state,		.hook	= hook_entry,		.size	= sizeof(*entry) + afinfo->route_key_size,	}; 	nf_queue_entry_get_refs(entry);	skb_dst_force(skb);	afinfo->saveroute(skb, entry);	status = qh->outfn(entry, queuenum); 	if (status < 0) {		nf_queue_entry_release_refs(entry);		goto err;	} 	return 0; err:	kfree(entry);	return status;} /* Packets leaving via this function must come back through nf_reinject(). */int nf_queue(struct sk_buff *skb, struct nf_hook_state *state,	     struct nf_hook_entry **entryp, unsigned int verdict){	struct nf_hook_entry *entry = *entryp;	int ret; 	ret = __nf_queue(skb, state, entry, verdict >> NF_VERDICT_QBITS);	if (ret < 0) {		if (ret == -ESRCH &&		    (verdict & NF_VERDICT_FLAG_QUEUE_BYPASS)) {			*entryp = rcu_dereference(entry->next);			return 1;		}		kfree_skb(skb);	} 	return 0;} static unsigned int nf_iterate(struct sk_buff *skb,			       struct nf_hook_state *state,			       struct nf_hook_entry **entryp){	unsigned int verdict; 	do {repeat:		verdict = nf_hook_entry_hookfn((*entryp), skb, state);		if (verdict != NF_ACCEPT) {			if (verdict != NF_REPEAT)				return verdict;			goto repeat;		}		*entryp = rcu_dereference((*entryp)->next);	} while (*entryp); 	return NF_ACCEPT;} void nf_reinject(struct nf_queue_entry *entry, unsigned int verdict){	struct nf_hook_entry *hook_entry = entry->hook;	struct sk_buff *skb = entry->skb;	const struct nf_afinfo *afinfo;	int err; 	nf_queue_entry_release_refs(entry); 	/* Continue traversal iff userspace said ok... */	if (verdict == NF_REPEAT)		verdict = nf_hook_entry_hookfn(hook_entry, skb, &entry->state); 	if (verdict == NF_ACCEPT) {		afinfo = nf_get_afinfo(entry->state.pf);		if (!afinfo || afinfo->reroute(entry->state.net, skb, entry) < 0)			verdict = NF_DROP;	} 	if (verdict == NF_ACCEPT) {		hook_entry = rcu_dereference(hook_entry->next);		if (hook_entry)next_hook:			verdict = nf_iterate(skb, &entry->state, &hook_entry);	} 	switch (verdict & NF_VERDICT_MASK) {	case NF_ACCEPT:	case NF_STOP:okfn:		local_bh_disable();		entry->state.okfn(entry->state.net, entry->state.sk, skb);		local_bh_enable();		break;	case NF_QUEUE:		err = nf_queue(skb, &entry->state, &hook_entry, verdict);		if (err == 1) {			if (hook_entry)				goto next_hook;			goto okfn;		}		break;	case NF_STOLEN:		break;	default:		kfree_skb(skb);	} 	kfree(entry);}EXPORT_SYMBOL(nf_reinject);