#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/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" /* * A queue handler may be registered for each protocol.  Each is protected by * long term mutex.  The handler must provide an an outfn() to accept packets * for queueing and must reinject all packets it receives, no matter what. */static const struct nf_queue_handler __rcu *queue_handler[NFPROTO_NUMPROTO] __read_mostly; static DEFINE_MUTEX(queue_handler_mutex); /* return EBUSY when somebody else is registered, return EEXIST if the * same handler is registered, return 0 in case of success. */int nf_register_queue_handler(u_int8_t pf, const struct nf_queue_handler *qh){	int ret;	const struct nf_queue_handler *old; 	if (pf >= ARRAY_SIZE(queue_handler))		return -EINVAL; 	mutex_lock(&queue_handler_mutex);	old = rcu_dereference_protected(queue_handler[pf],					lockdep_is_held(&queue_handler_mutex));	if (old == qh)		ret = -EEXIST;	else if (old)		ret = -EBUSY;	else {		rcu_assign_pointer(queue_handler[pf], qh);		ret = 0;	}	mutex_unlock(&queue_handler_mutex); 	return ret;}EXPORT_SYMBOL(nf_register_queue_handler); /* The caller must flush their queue before this */int nf_unregister_queue_handler(u_int8_t pf, const struct nf_queue_handler *qh){	const struct nf_queue_handler *old; 	if (pf >= ARRAY_SIZE(queue_handler))		return -EINVAL; 	mutex_lock(&queue_handler_mutex);	old = rcu_dereference_protected(queue_handler[pf],					lockdep_is_held(&queue_handler_mutex));	if (old && old != qh) {		mutex_unlock(&queue_handler_mutex);		return -EINVAL;	} 	rcu_assign_pointer(queue_handler[pf], NULL);	mutex_unlock(&queue_handler_mutex); 	synchronize_rcu(); 	return 0;}EXPORT_SYMBOL(nf_unregister_queue_handler); void nf_unregister_queue_handlers(const struct nf_queue_handler *qh){	u_int8_t pf; 	mutex_lock(&queue_handler_mutex);	for (pf = 0; pf < ARRAY_SIZE(queue_handler); pf++)  {		if (rcu_dereference_protected(				queue_handler[pf],				lockdep_is_held(&queue_handler_mutex)				) == qh)			rcu_assign_pointer(queue_handler[pf], NULL);	}	mutex_unlock(&queue_handler_mutex); 	synchronize_rcu();}EXPORT_SYMBOL_GPL(nf_unregister_queue_handlers); static void nf_queue_entry_release_refs(struct nf_queue_entry *entry){	/* Release those devices we held, or Alexey will kill me. */	if (entry->indev)		dev_put(entry->indev);	if (entry->outdev)		dev_put(entry->outdev);#ifdef CONFIG_BRIDGE_NETFILTER	if (entry->skb->nf_bridge) {		struct nf_bridge_info *nf_bridge = entry->skb->nf_bridge; 		if (nf_bridge->physindev)			dev_put(nf_bridge->physindev);		if (nf_bridge->physoutdev)			dev_put(nf_bridge->physoutdev);	}#endif	/* Drop reference to owner of hook which queued us. */	module_put(entry->elem->owner);} /* * Any packet that leaves via this function must come back * through nf_reinject(). */static int __nf_queue(struct sk_buff *skb,		      struct list_head *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 status = -ENOENT;	struct nf_queue_entry *entry = NULL;#ifdef CONFIG_BRIDGE_NETFILTER	struct net_device *physindev;	struct net_device *physoutdev;#endif	const struct nf_afinfo *afinfo;	const struct nf_queue_handler *qh; 	/* QUEUE == DROP if no one is waiting, to be safe. */	rcu_read_lock(); 	qh = rcu_dereference(queue_handler[pf]);	if (!qh) {		status = -ESRCH;		goto err_unlock;	} 	afinfo = nf_get_afinfo(pf);	if (!afinfo)		goto err_unlock; 	entry = kmalloc(sizeof(*entry) + afinfo->route_key_size, GFP_ATOMIC);	if (!entry) {		status = -ENOMEM;		goto err_unlock;	} 	*entry = (struct nf_queue_entry) {		.skb	= skb,		.elem	= list_entry(elem, struct nf_hook_ops, list),		.pf	= pf,		.hook	= hook,		.indev	= indev,		.outdev	= outdev,		.okfn	= okfn,	}; 	/* If it's going away, ignore hook. */	if (!try_module_get(entry->elem->owner)) {		status = -ECANCELED;		goto err_unlock;	}	/* Bump dev refs so they don't vanish while packet is out */	if (indev)		dev_hold(indev);	if (outdev)		dev_hold(outdev);#ifdef CONFIG_BRIDGE_NETFILTER	if (skb->nf_bridge) {		physindev = skb->nf_bridge->physindev;		if (physindev)			dev_hold(physindev);		physoutdev = skb->nf_bridge->physoutdev;		if (physoutdev)			dev_hold(physoutdev);	}#endif	skb_dst_force(skb);	afinfo->saveroute(skb, entry);	status = qh->outfn(entry, queuenum); 	rcu_read_unlock(); 	if (status < 0) {		nf_queue_entry_release_refs(entry);		goto err;	} 	return 0; err_unlock:	rcu_read_unlock();err:	kfree(entry);	return status;} int nf_queue(struct sk_buff *skb,	     struct list_head *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 sk_buff *segs;	int err;	unsigned int queued; 	if (!skb_is_gso(skb))		return __nf_queue(skb, elem, pf, hook, indev, outdev, okfn,				  queuenum); 	switch (pf) {	case NFPROTO_IPV4:		skb->protocol = htons(ETH_P_IP);		break;	case NFPROTO_IPV6:		skb->protocol = htons(ETH_P_IPV6);		break;	} 	segs = skb_gso_segment(skb, 0);	/* Does not use PTR_ERR to limit the number of error codes that can be	 * returned by nf_queue.  For instance, callers rely on -ECANCELED to mean	 * 'ignore this hook'.	 */	if (IS_ERR(segs))		return -EINVAL; 	queued = 0;	err = 0;	do {		struct sk_buff *nskb = segs->next; 		segs->next = NULL;		if (err == 0)			err = __nf_queue(segs, elem, pf, hook, indev,					   outdev, okfn, queuenum);		if (err == 0)			queued++;		else			kfree_skb(segs);		segs = nskb;	} while (segs); 	/* also free orig skb if only some segments were queued */	if (unlikely(err && queued))		err = 0;	if (err == 0)		kfree_skb(skb);	return err;} void nf_reinject(struct nf_queue_entry *entry, unsigned int verdict){	struct sk_buff *skb = entry->skb;	struct list_head *elem = &entry->elem->list;	const struct nf_afinfo *afinfo;	int err; 	rcu_read_lock(); 	nf_queue_entry_release_refs(entry); 	/* Continue traversal iff userspace said ok... */	if (verdict == NF_REPEAT) {		elem = elem->prev;		verdict = NF_ACCEPT;	} 	if (verdict == NF_ACCEPT) {		afinfo = nf_get_afinfo(entry->pf);		if (!afinfo || afinfo->reroute(skb, entry) < 0)			verdict = NF_DROP;	} 	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);	} 	switch (verdict & NF_VERDICT_MASK) {	case NF_ACCEPT:	case NF_STOP:		local_bh_disable();		entry->okfn(skb);		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);		if (err < 0) {			if (err == -ECANCELED)				goto next_hook;			if (err == -ESRCH &&			   (verdict & NF_VERDICT_FLAG_QUEUE_BYPASS))				goto next_hook;			kfree_skb(skb);		}		break;	case NF_STOLEN:	default:		kfree_skb(skb);	}	rcu_read_unlock();	kfree(entry);}EXPORT_SYMBOL(nf_reinject); #ifdef CONFIG_PROC_FSstatic void *seq_start(struct seq_file *seq, loff_t *pos){	if (*pos >= ARRAY_SIZE(queue_handler))		return NULL; 	return pos;} static void *seq_next(struct seq_file *s, void *v, loff_t *pos){	(*pos)++; 	if (*pos >= ARRAY_SIZE(queue_handler))		return NULL; 	return pos;} static void seq_stop(struct seq_file *s, void *v){ } static int seq_show(struct seq_file *s, void *v){	int ret;	loff_t *pos = v;	const struct nf_queue_handler *qh; 	rcu_read_lock();	qh = rcu_dereference(queue_handler[*pos]);	if (!qh)		ret = seq_printf(s, "%2lld NONE\n", *pos);	else		ret = seq_printf(s, "%2lld %s\n", *pos, qh->name);	rcu_read_unlock(); 	return ret;} static const struct seq_operations nfqueue_seq_ops = {	.start	= seq_start,	.next	= seq_next,	.stop	= seq_stop,	.show	= seq_show,}; static int nfqueue_open(struct inode *inode, struct file *file){	return seq_open(file, &nfqueue_seq_ops);} static const struct file_operations nfqueue_file_ops = {	.owner	 = THIS_MODULE,	.open	 = nfqueue_open,	.read	 = seq_read,	.llseek	 = seq_lseek,	.release = seq_release,};#endif /* PROC_FS */  int __init netfilter_queue_init(void){#ifdef CONFIG_PROC_FS	if (!proc_create("nf_queue", S_IRUGO,			 proc_net_netfilter, &nfqueue_file_ops))		return -1;#endif	return 0;}