#include <linux/config.h>#include <linux/kernel.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 "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 struct nf_queue_handler *queue_handler[NPROTO]; static DEFINE_RWLOCK(queue_handler_lock); /* 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(int pf, struct nf_queue_handler *qh){      	int ret; 	if (pf >= NPROTO)		return -EINVAL; 	write_lock_bh(&queue_handler_lock);	if (queue_handler[pf] == qh)		ret = -EEXIST;	else if (queue_handler[pf])		ret = -EBUSY;	else {		queue_handler[pf] = qh;		ret = 0;	}	write_unlock_bh(&queue_handler_lock); 	return ret;}EXPORT_SYMBOL(nf_register_queue_handler); /* The caller must flush their queue before this */int nf_unregister_queue_handler(int pf){	if (pf >= NPROTO)		return -EINVAL; 	write_lock_bh(&queue_handler_lock);	queue_handler[pf] = NULL;	write_unlock_bh(&queue_handler_lock);		return 0;}EXPORT_SYMBOL(nf_unregister_queue_handler); void nf_unregister_queue_handlers(struct nf_queue_handler *qh){	int pf; 	write_lock_bh(&queue_handler_lock);	for (pf = 0; pf < NPROTO; pf++)  {		if (queue_handler[pf] == qh)			queue_handler[pf] = NULL;	}	write_unlock_bh(&queue_handler_lock);}EXPORT_SYMBOL_GPL(nf_unregister_queue_handlers); /*  * Any packet that leaves via this function must come back  * through nf_reinject(). */int nf_queue(struct sk_buff **skb, 	     struct list_head *elem, 	     int pf, unsigned int hook,	     struct net_device *indev,	     struct net_device *outdev,	     int (*okfn)(struct sk_buff *),	     unsigned int queuenum){	int status;	struct nf_info *info;#ifdef CONFIG_BRIDGE_NETFILTER	struct net_device *physindev = NULL;	struct net_device *physoutdev = NULL;#endif	struct nf_afinfo *afinfo; 	/* QUEUE == DROP if noone is waiting, to be safe. */	read_lock(&queue_handler_lock);	if (!queue_handler[pf]) {		read_unlock(&queue_handler_lock);		kfree_skb(*skb);		return 1;	} 	afinfo = nf_get_afinfo(pf);	if (!afinfo) {		read_unlock(&queue_handler_lock);		kfree_skb(*skb);		return 1;	} 	info = kmalloc(sizeof(*info) + afinfo->route_key_size, GFP_ATOMIC);	if (!info) {		if (net_ratelimit())			printk(KERN_ERR "OOM queueing packet %p\n",			       *skb);		read_unlock(&queue_handler_lock);		kfree_skb(*skb);		return 1;	} 	*info = (struct nf_info) { 		(struct nf_hook_ops *)elem, pf, hook, indev, outdev, okfn }; 	/* If it's going away, ignore hook. */	if (!try_module_get(info->elem->owner)) {		read_unlock(&queue_handler_lock);		kfree(info);		return 0;	} 	/* 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	afinfo->saveroute(*skb, info);	status = queue_handler[pf]->outfn(*skb, info, queuenum,					  queue_handler[pf]->data); 	read_unlock(&queue_handler_lock); 	if (status < 0) {		/* James M doesn't say fuck enough. */		if (indev) dev_put(indev);		if (outdev) dev_put(outdev);#ifdef CONFIG_BRIDGE_NETFILTER		if (physindev) dev_put(physindev);		if (physoutdev) dev_put(physoutdev);#endif		module_put(info->elem->owner);		kfree(info);		kfree_skb(*skb); 		return 1;	} 	return 1;} void nf_reinject(struct sk_buff *skb, struct nf_info *info,		 unsigned int verdict){	struct list_head *elem = &info->elem->list;	struct list_head *i;	struct nf_afinfo *afinfo; 	rcu_read_lock(); 	/* Release those devices we held, or Alexey will kill me. */	if (info->indev) dev_put(info->indev);	if (info->outdev) dev_put(info->outdev);#ifdef CONFIG_BRIDGE_NETFILTER	if (skb->nf_bridge) {		if (skb->nf_bridge->physindev)			dev_put(skb->nf_bridge->physindev);		if (skb->nf_bridge->physoutdev)			dev_put(skb->nf_bridge->physoutdev);	}#endif 	/* Drop reference to owner of hook which queued us. */	module_put(info->elem->owner); 	list_for_each_rcu(i, &nf_hooks[info->pf][info->hook]) {		if (i == elem)   			break;  	}  	if (i == &nf_hooks[info->pf][info->hook]) {		/* The module which sent it to userspace is gone. */		NFDEBUG("%s: module disappeared, dropping packet.\n",			__FUNCTION__);		verdict = NF_DROP;	} 	/* Continue traversal iff userspace said ok... */	if (verdict == NF_REPEAT) {		elem = elem->prev;		verdict = NF_ACCEPT;	} 	if (verdict == NF_ACCEPT) {		afinfo = nf_get_afinfo(info->pf);		if (!afinfo || afinfo->reroute(&skb, info) < 0)			verdict = NF_DROP;	} 	if (verdict == NF_ACCEPT) {	next_hook:		verdict = nf_iterate(&nf_hooks[info->pf][info->hook],				     &skb, info->hook, 				     info->indev, info->outdev, &elem,				     info->okfn, INT_MIN);	} 	switch (verdict & NF_VERDICT_MASK) {	case NF_ACCEPT:		info->okfn(skb);		break; 	case NF_QUEUE:		if (!nf_queue(&skb, elem, info->pf, info->hook, 			      info->indev, info->outdev, info->okfn,			      verdict >> NF_VERDICT_BITS))			goto next_hook;		break;	}	rcu_read_unlock(); 	if (verdict == NF_DROP)		kfree_skb(skb); 	kfree(info);	return;}EXPORT_SYMBOL(nf_reinject); #ifdef CONFIG_PROC_FSstatic void *seq_start(struct seq_file *seq, loff_t *pos){	if (*pos >= NPROTO)		return NULL; 	return pos;} static void *seq_next(struct seq_file *s, void *v, loff_t *pos){	(*pos)++; 	if (*pos >= NPROTO)		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;	struct nf_queue_handler *qh; 	read_lock_bh(&queue_handler_lock);	qh = queue_handler[*pos];	if (!qh)		ret = seq_printf(s, "%2lld NONE\n", *pos);	else		ret = seq_printf(s, "%2lld %s\n", *pos, qh->name);	read_unlock_bh(&queue_handler_lock); 	return ret;} static 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 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	struct proc_dir_entry *pde; 	pde = create_proc_entry("nf_queue", S_IRUGO, proc_net_netfilter);	if (!pde)		return -1;	pde->proc_fops = &nfqueue_file_ops;#endif	return 0;}