[mirror_ubuntu-jammy-kernel.git] / net / netfilter / nf_queue.c

#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_FS
static 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;
}
Commit	Line	Data
f6ebe77f HW	1	#include <linux/kernel.h>
	2	#include <linux/init.h>
	3	#include <linux/module.h>
	4	#include <linux/proc_fs.h>
	5	#include <linux/skbuff.h>
	6	#include <linux/netfilter.h>
bbd86b9f	7	#include <linux/seq_file.h>
7a11b984	8	#include <linux/rcupdate.h>
f6ebe77f HW	9	#include <net/protocol.h>
	10
	11	#include "nf_internals.h"
	12
	13	/*
	14	* A queue handler may be registered for each protocol. Each is protected by
	15	* long term mutex. The handler must provide an an outfn() to accept packets
	16	* for queueing and must reinject all packets it receives, no matter what.
	17	*/
bbd86b9f	18	static struct nf_queue_handler *queue_handler[NPROTO];
f6ebe77f HW	19
	20	static DEFINE_RWLOCK(queue_handler_lock);
	21
d72367b6 HW	22	/* return EBUSY when somebody else is registered, return EEXIST if the
d72367b6 HW	23	* same handler is registered, return 0 in case of success. */
bbd86b9f	24	int nf_register_queue_handler(int pf, struct nf_queue_handler *qh)
f6ebe77f HW	25	{
	26	int ret;
	27
	28	if (pf >= NPROTO)
	29	return -EINVAL;
	30
	31	write_lock_bh(&queue_handler_lock);
d72367b6 HW	32	if (queue_handler[pf] == qh)
	33	ret = -EEXIST;
	34	else if (queue_handler[pf])
f6ebe77f HW	35	ret = -EBUSY;
f6ebe77f HW	36	else {
bbd86b9f	37	queue_handler[pf] = qh;
f6ebe77f HW	38	ret = 0;
	39	}
	40	write_unlock_bh(&queue_handler_lock);
	41
	42	return ret;
	43	}
	44	EXPORT_SYMBOL(nf_register_queue_handler);
	45
	46	/* The caller must flush their queue before this */
	47	int nf_unregister_queue_handler(int pf)
	48	{
	49	if (pf >= NPROTO)
	50	return -EINVAL;
	51
	52	write_lock_bh(&queue_handler_lock);
bbd86b9f	53	queue_handler[pf] = NULL;
f6ebe77f HW	54	write_unlock_bh(&queue_handler_lock);
	55
	56	return 0;
	57	}
	58	EXPORT_SYMBOL(nf_unregister_queue_handler);
	59
bbd86b9f	60	void nf_unregister_queue_handlers(struct nf_queue_handler *qh)
f6ebe77f HW	61	{
	62	int pf;
	63
	64	write_lock_bh(&queue_handler_lock);
	65	for (pf = 0; pf < NPROTO; pf++) {
bbd86b9f HW	66	if (queue_handler[pf] == qh)
bbd86b9f HW	67	queue_handler[pf] = NULL;
f6ebe77f HW	68	}
	69	write_unlock_bh(&queue_handler_lock);
	70	}
	71	EXPORT_SYMBOL_GPL(nf_unregister_queue_handlers);
	72
	73	/*
	74	* Any packet that leaves via this function must come back
	75	* through nf_reinject().
	76	*/
	77	int nf_queue(struct sk_buff **skb,
	78	struct list_head *elem,
	79	int pf, unsigned int hook,
	80	struct net_device *indev,
	81	struct net_device *outdev,
	82	int (okfn)(struct sk_buff ),
	83	unsigned int queuenum)
	84	{
	85	int status;
	86	struct nf_info *info;
	87	#ifdef CONFIG_BRIDGE_NETFILTER
	88	struct net_device *physindev = NULL;
	89	struct net_device *physoutdev = NULL;
	90	#endif
bce8032e	91	struct nf_afinfo *afinfo;
f6ebe77f HW	92
	93	/* QUEUE == DROP if noone is waiting, to be safe. */
	94	read_lock(&queue_handler_lock);
e121e9ec	95	if (!queue_handler[pf]) {
f6ebe77f HW	96	read_unlock(&queue_handler_lock);
	97	kfree_skb(*skb);
	98	return 1;
	99	}
	100
bce8032e PM	101	afinfo = nf_get_afinfo(pf);
	102	if (!afinfo) {
	103	read_unlock(&queue_handler_lock);
	104	kfree_skb(*skb);
	105	return 1;
	106	}
	107
	108	info = kmalloc(sizeof(*info) + afinfo->route_key_size, GFP_ATOMIC);
f6ebe77f HW	109	if (!info) {
	110	if (net_ratelimit())
	111	printk(KERN_ERR "OOM queueing packet %p\n",
	112	*skb);
	113	read_unlock(&queue_handler_lock);
	114	kfree_skb(*skb);
	115	return 1;
	116	}
	117
	118	*info = (struct nf_info) {
	119	(struct nf_hook_ops *)elem, pf, hook, indev, outdev, okfn };
	120
	121	/* If it's going away, ignore hook. */
	122	if (!try_module_get(info->elem->owner)) {
	123	read_unlock(&queue_handler_lock);
	124	kfree(info);
	125	return 0;
	126	}
	127
	128	/* Bump dev refs so they don't vanish while packet is out */
	129	if (indev) dev_hold(indev);
	130	if (outdev) dev_hold(outdev);
	131
	132	#ifdef CONFIG_BRIDGE_NETFILTER
	133	if ((*skb)->nf_bridge) {
	134	physindev = (*skb)->nf_bridge->physindev;
	135	if (physindev) dev_hold(physindev);
	136	physoutdev = (*skb)->nf_bridge->physoutdev;
	137	if (physoutdev) dev_hold(physoutdev);
	138	}
	139	#endif
bce8032e	140	afinfo->saveroute(*skb, info);
bbd86b9f HW	141	status = queue_handler[pf]->outfn(*skb, info, queuenum,
bbd86b9f HW	142	queue_handler[pf]->data);
f6ebe77f	143
f6ebe77f HW	144	read_unlock(&queue_handler_lock);
	145
	146	if (status < 0) {
	147	/* James M doesn't say fuck enough. */
	148	if (indev) dev_put(indev);
	149	if (outdev) dev_put(outdev);
	150	#ifdef CONFIG_BRIDGE_NETFILTER
	151	if (physindev) dev_put(physindev);
	152	if (physoutdev) dev_put(physoutdev);
	153	#endif
	154	module_put(info->elem->owner);
	155	kfree(info);
	156	kfree_skb(*skb);
	157
	158	return 1;
	159	}
	160
	161	return 1;
	162	}
	163
	164	void nf_reinject(struct sk_buff skb, struct nf_info info,
	165	unsigned int verdict)
	166	{
	167	struct list_head *elem = &info->elem->list;
	168	struct list_head *i;
bce8032e	169	struct nf_afinfo *afinfo;
f6ebe77f HW	170
	171	rcu_read_lock();
	172
	173	/* Release those devices we held, or Alexey will kill me. */
	174	if (info->indev) dev_put(info->indev);
	175	if (info->outdev) dev_put(info->outdev);
	176	#ifdef CONFIG_BRIDGE_NETFILTER
	177	if (skb->nf_bridge) {
	178	if (skb->nf_bridge->physindev)
	179	dev_put(skb->nf_bridge->physindev);
	180	if (skb->nf_bridge->physoutdev)
	181	dev_put(skb->nf_bridge->physoutdev);
	182	}
	183	#endif
	184
	185	/* Drop reference to owner of hook which queued us. */
	186	module_put(info->elem->owner);
	187
	188	list_for_each_rcu(i, &nf_hooks[info->pf][info->hook]) {
	189	if (i == elem)
	190	break;
	191	}
	192
45fe4dc0	193	if (i == &nf_hooks[info->pf][info->hook]) {
f6ebe77f HW	194	/* The module which sent it to userspace is gone. */
	195	NFDEBUG("%s: module disappeared, dropping packet.\n",
	196	__FUNCTION__);
	197	verdict = NF_DROP;
	198	}
	199
	200	/* Continue traversal iff userspace said ok... */
	201	if (verdict == NF_REPEAT) {
	202	elem = elem->prev;
	203	verdict = NF_ACCEPT;
	204	}
	205
7a11b984	206	if (verdict == NF_ACCEPT) {
bce8032e PM	207	afinfo = nf_get_afinfo(info->pf);
bce8032e PM	208	if (!afinfo \|\| afinfo->reroute(&skb, info) < 0)
7a11b984 PM	209	verdict = NF_DROP;
	210	}
	211
f6ebe77f HW	212	if (verdict == NF_ACCEPT) {
	213	next_hook:
	214	verdict = nf_iterate(&nf_hooks[info->pf][info->hook],
	215	&skb, info->hook,
	216	info->indev, info->outdev, &elem,
	217	info->okfn, INT_MIN);
	218	}
	219
	220	switch (verdict & NF_VERDICT_MASK) {
	221	case NF_ACCEPT:
	222	info->okfn(skb);
	223	break;
	224
	225	case NF_QUEUE:
	226	if (!nf_queue(&skb, elem, info->pf, info->hook,
	227	info->indev, info->outdev, info->okfn,
	228	verdict >> NF_VERDICT_BITS))
	229	goto next_hook;
	230	break;
	231	}
	232	rcu_read_unlock();
	233
	234	if (verdict == NF_DROP)
	235	kfree_skb(skb);
	236
	237	kfree(info);
	238	return;
	239	}
	240	EXPORT_SYMBOL(nf_reinject);
	241
bbd86b9f HW	242	#ifdef CONFIG_PROC_FS
	243	static void seq_start(struct seq_file seq, loff_t *pos)
	244	{
	245	if (*pos >= NPROTO)
	246	return NULL;
	247
	248	return pos;
	249	}
	250
	251	static void seq_next(struct seq_file s, void v, loff_t pos)
	252	{
	253	(*pos)++;
	254
	255	if (*pos >= NPROTO)
	256	return NULL;
	257
	258	return pos;
	259	}
	260
	261	static void seq_stop(struct seq_file s, void v)
	262	{
	263
	264	}
	265
	266	static int seq_show(struct seq_file s, void v)
	267	{
	268	int ret;
	269	loff_t *pos = v;
	270	struct nf_queue_handler *qh;
	271
	272	read_lock_bh(&queue_handler_lock);
	273	qh = queue_handler[*pos];
	274	if (!qh)
	275	ret = seq_printf(s, "%2lld NONE\n", *pos);
	276	else
	277	ret = seq_printf(s, "%2lld %s\n", *pos, qh->name);
	278	read_unlock_bh(&queue_handler_lock);
	279
	280	return ret;
	281	}
	282
	283	static struct seq_operations nfqueue_seq_ops = {
	284	.start = seq_start,
	285	.next = seq_next,
	286	.stop = seq_stop,
	287	.show = seq_show,
	288	};
	289
	290	static int nfqueue_open(struct inode inode, struct file file)
	291	{
	292	return seq_open(file, &nfqueue_seq_ops);
	293	}
	294
	295	static struct file_operations nfqueue_file_ops = {
	296	.owner = THIS_MODULE,
	297	.open = nfqueue_open,
	298	.read = seq_read,
	299	.llseek = seq_lseek,
	300	.release = seq_release,
	301	};
	302	#endif /* PROC_FS */
	303
	304
f6ebe77f HW	305	int __init netfilter_queue_init(void)
f6ebe77f HW	306	{
bbd86b9f HW	307	#ifdef CONFIG_PROC_FS
bbd86b9f HW	308	struct proc_dir_entry *pde;
f6ebe77f	309
bbd86b9f	310	pde = create_proc_entry("nf_queue", S_IRUGO, proc_net_netfilter);
e02f7d16	311	if (!pde)
bbd86b9f	312	return -1;
bbd86b9f HW	313	pde->proc_fops = &nfqueue_file_ops;
bbd86b9f HW	314	#endif
f6ebe77f HW	315	return 0;
	316	}
	317