[mirror_ubuntu-jammy-kernel.git] / net / ieee802154 / 6lowpan / reassembly.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*	6LoWPAN fragment reassembly
 *
 *	Authors:
 *	Alexander Aring		<aar@pengutronix.de>
 *
 *	Based on: net/ipv6/reassembly.c
 */

#define pr_fmt(fmt) "6LoWPAN: " fmt

#include <linux/net.h>
#include <linux/list.h>
#include <linux/netdevice.h>
#include <linux/random.h>
#include <linux/jhash.h>
#include <linux/skbuff.h>
#include <linux/slab.h>
#include <linux/export.h>

#include <net/ieee802154_netdev.h>
#include <net/6lowpan.h>
#include <net/ipv6_frag.h>
#include <net/inet_frag.h>
#include <net/ip.h>

#include "6lowpan_i.h"

static const char lowpan_frags_cache_name[] = "lowpan-frags";

static struct inet_frags lowpan_frags;

static int lowpan_frag_reasm(struct lowpan_frag_queue *fq, struct sk_buff *skb,
			     struct sk_buff *prev,  struct net_device *ldev);

static void lowpan_frag_init(struct inet_frag_queue *q, const void *a)
{
	const struct frag_lowpan_compare_key *key = a;

	BUILD_BUG_ON(sizeof(*key) > sizeof(q->key));
	memcpy(&q->key, key, sizeof(*key));
}

static void lowpan_frag_expire(struct timer_list *t)
{
	struct inet_frag_queue *frag = from_timer(frag, t, timer);
	struct frag_queue *fq;

	fq = container_of(frag, struct frag_queue, q);

	spin_lock(&fq->q.lock);

	if (fq->q.flags & INET_FRAG_COMPLETE)
		goto out;

	inet_frag_kill(&fq->q);
out:
	spin_unlock(&fq->q.lock);
	inet_frag_put(&fq->q);
}

static inline struct lowpan_frag_queue *
fq_find(struct net *net, const struct lowpan_802154_cb *cb,
	const struct ieee802154_addr *src,
	const struct ieee802154_addr *dst)
{
	struct netns_ieee802154_lowpan *ieee802154_lowpan =
		net_ieee802154_lowpan(net);
	struct frag_lowpan_compare_key key = {};
	struct inet_frag_queue *q;

	key.tag = cb->d_tag;
	key.d_size = cb->d_size;
	key.src = *src;
	key.dst = *dst;

	q = inet_frag_find(ieee802154_lowpan->fqdir, &key);
	if (!q)
		return NULL;

	return container_of(q, struct lowpan_frag_queue, q);
}

static int lowpan_frag_queue(struct lowpan_frag_queue *fq,
			     struct sk_buff *skb, u8 frag_type)
{
	struct sk_buff *prev_tail;
	struct net_device *ldev;
	int end, offset, err;

	/* inet_frag_queue_* functions use skb->cb; see struct ipfrag_skb_cb
	 * in inet_fragment.c
	 */
	BUILD_BUG_ON(sizeof(struct lowpan_802154_cb) > sizeof(struct inet_skb_parm));
	BUILD_BUG_ON(sizeof(struct lowpan_802154_cb) > sizeof(struct inet6_skb_parm));

	if (fq->q.flags & INET_FRAG_COMPLETE)
		goto err;

	offset = lowpan_802154_cb(skb)->d_offset << 3;
	end = lowpan_802154_cb(skb)->d_size;

	/* Is this the final fragment? */
	if (offset + skb->len == end) {
		/* If we already have some bits beyond end
		 * or have different end, the segment is corrupted.
		 */
		if (end < fq->q.len ||
		    ((fq->q.flags & INET_FRAG_LAST_IN) && end != fq->q.len))
			goto err;
		fq->q.flags |= INET_FRAG_LAST_IN;
		fq->q.len = end;
	} else {
		if (end > fq->q.len) {
			/* Some bits beyond end -> corruption. */
			if (fq->q.flags & INET_FRAG_LAST_IN)
				goto err;
			fq->q.len = end;
		}
	}

	ldev = skb->dev;
	if (ldev)
		skb->dev = NULL;
	barrier();

	prev_tail = fq->q.fragments_tail;
	err = inet_frag_queue_insert(&fq->q, skb, offset, end);
	if (err)
		goto err;

	fq->q.stamp = skb->tstamp;
	if (frag_type == LOWPAN_DISPATCH_FRAG1)
		fq->q.flags |= INET_FRAG_FIRST_IN;

	fq->q.meat += skb->len;
	add_frag_mem_limit(fq->q.fqdir, skb->truesize);

	if (fq->q.flags == (INET_FRAG_FIRST_IN | INET_FRAG_LAST_IN) &&
	    fq->q.meat == fq->q.len) {
		int res;
		unsigned long orefdst = skb->_skb_refdst;

		skb->_skb_refdst = 0UL;
		res = lowpan_frag_reasm(fq, skb, prev_tail, ldev);
		skb->_skb_refdst = orefdst;
		return res;
	}
	skb_dst_drop(skb);

	return -1;
err:
	kfree_skb(skb);
	return -1;
}

/*	Check if this packet is complete.
 *
 *	It is called with locked fq, and caller must check that
 *	queue is eligible for reassembly i.e. it is not COMPLETE,
 *	the last and the first frames arrived and all the bits are here.
 */
static int lowpan_frag_reasm(struct lowpan_frag_queue *fq, struct sk_buff *skb,
			     struct sk_buff *prev_tail, struct net_device *ldev)
{
	void *reasm_data;

	inet_frag_kill(&fq->q);

	reasm_data = inet_frag_reasm_prepare(&fq->q, skb, prev_tail);
	if (!reasm_data)
		goto out_oom;
	inet_frag_reasm_finish(&fq->q, skb, reasm_data, false);

	skb->dev = ldev;
	skb->tstamp = fq->q.stamp;
	fq->q.rb_fragments = RB_ROOT;
	fq->q.fragments_tail = NULL;
	fq->q.last_run_head = NULL;

	return 1;
out_oom:
	net_dbg_ratelimited("lowpan_frag_reasm: no memory for reassembly\n");
	return -1;
}

static int lowpan_frag_rx_handlers_result(struct sk_buff *skb,
					  lowpan_rx_result res)
{
	switch (res) {
	case RX_QUEUED:
		return NET_RX_SUCCESS;
	case RX_CONTINUE:
		/* nobody cared about this packet */
		net_warn_ratelimited("%s: received unknown dispatch\n",
				     __func__);

		fallthrough;
	default:
		/* all others failure */
		return NET_RX_DROP;
	}
}

static lowpan_rx_result lowpan_frag_rx_h_iphc(struct sk_buff *skb)
{
	int ret;

	if (!lowpan_is_iphc(*skb_network_header(skb)))
		return RX_CONTINUE;

	ret = lowpan_iphc_decompress(skb);
	if (ret < 0)
		return RX_DROP;

	return RX_QUEUED;
}

static int lowpan_invoke_frag_rx_handlers(struct sk_buff *skb)
{
	lowpan_rx_result res;

#define CALL_RXH(rxh)			\
	do {				\
		res = rxh(skb);	\
		if (res != RX_CONTINUE)	\
			goto rxh_next;	\
	} while (0)

	/* likely at first */
	CALL_RXH(lowpan_frag_rx_h_iphc);
	CALL_RXH(lowpan_rx_h_ipv6);

rxh_next:
	return lowpan_frag_rx_handlers_result(skb, res);
#undef CALL_RXH
}

#define LOWPAN_FRAG_DGRAM_SIZE_HIGH_MASK	0x07
#define LOWPAN_FRAG_DGRAM_SIZE_HIGH_SHIFT	8

static int lowpan_get_cb(struct sk_buff *skb, u8 frag_type,
			 struct lowpan_802154_cb *cb)
{
	bool fail;
	u8 high = 0, low = 0;
	__be16 d_tag = 0;

	fail = lowpan_fetch_skb(skb, &high, 1);
	fail |= lowpan_fetch_skb(skb, &low, 1);
	/* remove the dispatch value and use first three bits as high value
	 * for the datagram size
	 */
	cb->d_size = (high & LOWPAN_FRAG_DGRAM_SIZE_HIGH_MASK) <<
		LOWPAN_FRAG_DGRAM_SIZE_HIGH_SHIFT | low;
	fail |= lowpan_fetch_skb(skb, &d_tag, 2);
	cb->d_tag = ntohs(d_tag);

	if (frag_type == LOWPAN_DISPATCH_FRAGN) {
		fail |= lowpan_fetch_skb(skb, &cb->d_offset, 1);
	} else {
		skb_reset_network_header(skb);
		cb->d_offset = 0;
		/* check if datagram_size has ipv6hdr on FRAG1 */
		fail |= cb->d_size < sizeof(struct ipv6hdr);
		/* check if we can dereference the dispatch value */
		fail |= !skb->len;
	}

	if (unlikely(fail))
		return -EIO;

	return 0;
}

int lowpan_frag_rcv(struct sk_buff *skb, u8 frag_type)
{
	struct lowpan_frag_queue *fq;
	struct net *net = dev_net(skb->dev);
	struct lowpan_802154_cb *cb = lowpan_802154_cb(skb);
	struct ieee802154_hdr hdr = {};
	int err;

	if (ieee802154_hdr_peek_addrs(skb, &hdr) < 0)
		goto err;

	err = lowpan_get_cb(skb, frag_type, cb);
	if (err < 0)
		goto err;

	if (frag_type == LOWPAN_DISPATCH_FRAG1) {
		err = lowpan_invoke_frag_rx_handlers(skb);
		if (err == NET_RX_DROP)
			goto err;
	}

	if (cb->d_size > IPV6_MIN_MTU) {
		net_warn_ratelimited("lowpan_frag_rcv: datagram size exceeds MTU\n");
		goto err;
	}

	fq = fq_find(net, cb, &hdr.source, &hdr.dest);
	if (fq != NULL) {
		int ret;

		spin_lock(&fq->q.lock);
		ret = lowpan_frag_queue(fq, skb, frag_type);
		spin_unlock(&fq->q.lock);

		inet_frag_put(&fq->q);
		return ret;
	}

err:
	kfree_skb(skb);
	return -1;
}

#ifdef CONFIG_SYSCTL

static struct ctl_table lowpan_frags_ns_ctl_table[] = {
	{
		.procname	= "6lowpanfrag_high_thresh",
		.maxlen		= sizeof(unsigned long),
		.mode		= 0644,
		.proc_handler	= proc_doulongvec_minmax,
	},
	{
		.procname	= "6lowpanfrag_low_thresh",
		.maxlen		= sizeof(unsigned long),
		.mode		= 0644,
		.proc_handler	= proc_doulongvec_minmax,
	},
	{
		.procname	= "6lowpanfrag_time",
		.maxlen		= sizeof(int),
		.mode		= 0644,
		.proc_handler	= proc_dointvec_jiffies,
	},
	{ }
};

/* secret interval has been deprecated */
static int lowpan_frags_secret_interval_unused;
static struct ctl_table lowpan_frags_ctl_table[] = {
	{
		.procname	= "6lowpanfrag_secret_interval",
		.data		= &lowpan_frags_secret_interval_unused,
		.maxlen		= sizeof(int),
		.mode		= 0644,
		.proc_handler	= proc_dointvec_jiffies,
	},
	{ }
};

static int __net_init lowpan_frags_ns_sysctl_register(struct net *net)
{
	struct ctl_table *table;
	struct ctl_table_header *hdr;
	struct netns_ieee802154_lowpan *ieee802154_lowpan =
		net_ieee802154_lowpan(net);

	table = lowpan_frags_ns_ctl_table;
	if (!net_eq(net, &init_net)) {
		table = kmemdup(table, sizeof(lowpan_frags_ns_ctl_table),
				GFP_KERNEL);
		if (table == NULL)
			goto err_alloc;

		/* Don't export sysctls to unprivileged users */
		if (net->user_ns != &init_user_ns)
			table[0].procname = NULL;
	}

	table[0].data	= &ieee802154_lowpan->fqdir->high_thresh;
	table[0].extra1	= &ieee802154_lowpan->fqdir->low_thresh;
	table[1].data	= &ieee802154_lowpan->fqdir->low_thresh;
	table[1].extra2	= &ieee802154_lowpan->fqdir->high_thresh;
	table[2].data	= &ieee802154_lowpan->fqdir->timeout;

	hdr = register_net_sysctl(net, "net/ieee802154/6lowpan", table);
	if (hdr == NULL)
		goto err_reg;

	ieee802154_lowpan->sysctl.frags_hdr = hdr;
	return 0;

err_reg:
	if (!net_eq(net, &init_net))
		kfree(table);
err_alloc:
	return -ENOMEM;
}

static void __net_exit lowpan_frags_ns_sysctl_unregister(struct net *net)
{
	struct ctl_table *table;
	struct netns_ieee802154_lowpan *ieee802154_lowpan =
		net_ieee802154_lowpan(net);

	table = ieee802154_lowpan->sysctl.frags_hdr->ctl_table_arg;
	unregister_net_sysctl_table(ieee802154_lowpan->sysctl.frags_hdr);
	if (!net_eq(net, &init_net))
		kfree(table);
}

static struct ctl_table_header *lowpan_ctl_header;

static int __init lowpan_frags_sysctl_register(void)
{
	lowpan_ctl_header = register_net_sysctl(&init_net,
						"net/ieee802154/6lowpan",
						lowpan_frags_ctl_table);
	return lowpan_ctl_header == NULL ? -ENOMEM : 0;
}

static void lowpan_frags_sysctl_unregister(void)
{
	unregister_net_sysctl_table(lowpan_ctl_header);
}
#else
static inline int lowpan_frags_ns_sysctl_register(struct net *net)
{
	return 0;
}

static inline void lowpan_frags_ns_sysctl_unregister(struct net *net)
{
}

static inline int __init lowpan_frags_sysctl_register(void)
{
	return 0;
}

static inline void lowpan_frags_sysctl_unregister(void)
{
}
#endif

static int __net_init lowpan_frags_init_net(struct net *net)
{
	struct netns_ieee802154_lowpan *ieee802154_lowpan =
		net_ieee802154_lowpan(net);
	int res;


	res = fqdir_init(&ieee802154_lowpan->fqdir, &lowpan_frags, net);
	if (res < 0)
		return res;

	ieee802154_lowpan->fqdir->high_thresh = IPV6_FRAG_HIGH_THRESH;
	ieee802154_lowpan->fqdir->low_thresh = IPV6_FRAG_LOW_THRESH;
	ieee802154_lowpan->fqdir->timeout = IPV6_FRAG_TIMEOUT;

	res = lowpan_frags_ns_sysctl_register(net);
	if (res < 0)
		fqdir_exit(ieee802154_lowpan->fqdir);
	return res;
}

static void __net_exit lowpan_frags_pre_exit_net(struct net *net)
{
	struct netns_ieee802154_lowpan *ieee802154_lowpan =
		net_ieee802154_lowpan(net);

	fqdir_pre_exit(ieee802154_lowpan->fqdir);
}

static void __net_exit lowpan_frags_exit_net(struct net *net)
{
	struct netns_ieee802154_lowpan *ieee802154_lowpan =
		net_ieee802154_lowpan(net);

	lowpan_frags_ns_sysctl_unregister(net);
	fqdir_exit(ieee802154_lowpan->fqdir);
}

static struct pernet_operations lowpan_frags_ops = {
	.init		= lowpan_frags_init_net,
	.pre_exit	= lowpan_frags_pre_exit_net,
	.exit		= lowpan_frags_exit_net,
};

static u32 lowpan_key_hashfn(const void *data, u32 len, u32 seed)
{
	return jhash2(data,
		      sizeof(struct frag_lowpan_compare_key) / sizeof(u32), seed);
}

static u32 lowpan_obj_hashfn(const void *data, u32 len, u32 seed)
{
	const struct inet_frag_queue *fq = data;

	return jhash2((const u32 *)&fq->key,
		      sizeof(struct frag_lowpan_compare_key) / sizeof(u32), seed);
}

static int lowpan_obj_cmpfn(struct rhashtable_compare_arg *arg, const void *ptr)
{
	const struct frag_lowpan_compare_key *key = arg->key;
	const struct inet_frag_queue *fq = ptr;

	return !!memcmp(&fq->key, key, sizeof(*key));
}

static const struct rhashtable_params lowpan_rhash_params = {
	.head_offset		= offsetof(struct inet_frag_queue, node),
	.hashfn			= lowpan_key_hashfn,
	.obj_hashfn		= lowpan_obj_hashfn,
	.obj_cmpfn		= lowpan_obj_cmpfn,
	.automatic_shrinking	= true,
};

int __init lowpan_net_frag_init(void)
{
	int ret;

	lowpan_frags.constructor = lowpan_frag_init;
	lowpan_frags.destructor = NULL;
	lowpan_frags.qsize = sizeof(struct frag_queue);
	lowpan_frags.frag_expire = lowpan_frag_expire;
	lowpan_frags.frags_cache_name = lowpan_frags_cache_name;
	lowpan_frags.rhash_params = lowpan_rhash_params;
	ret = inet_frags_init(&lowpan_frags);
	if (ret)
		goto out;

	ret = lowpan_frags_sysctl_register();
	if (ret)
		goto err_sysctl;

	ret = register_pernet_subsys(&lowpan_frags_ops);
	if (ret)
		goto err_pernet;
out:
	return ret;
err_pernet:
	lowpan_frags_sysctl_unregister();
err_sysctl:
	inet_frags_fini(&lowpan_frags);
	return ret;
}

void lowpan_net_frag_exit(void)
{
	lowpan_frags_sysctl_unregister();
	unregister_pernet_subsys(&lowpan_frags_ops);
	inet_frags_fini(&lowpan_frags);
}
Commit	Line	Data
2874c5fd	1	// SPDX-License-Identifier: GPL-2.0-or-later
7240cdec	2	/* 6LoWPAN fragment reassembly
7240cdec AA	3	*
	4	* Authors:
	5	* Alexander Aring <aar@pengutronix.de>
	6	*
	7	* Based on: net/ipv6/reassembly.c
7240cdec AA	8	*/
	9
	10	#define pr_fmt(fmt) "6LoWPAN: " fmt
	11
	12	#include <linux/net.h>
	13	#include <linux/list.h>
	14	#include <linux/netdevice.h>
	15	#include <linux/random.h>
	16	#include <linux/jhash.h>
	17	#include <linux/skbuff.h>
	18	#include <linux/slab.h>
	19	#include <linux/export.h>
	20
	21	#include <net/ieee802154_netdev.h>
cefc8c8a	22	#include <net/6lowpan.h>
70b095c8	23	#include <net/ipv6_frag.h>
7240cdec	24	#include <net/inet_frag.h>
254c5dbe	25	#include <net/ip.h>
7240cdec	26
8691ee59	27	#include "6lowpan_i.h"
7240cdec	28
d4ad4d22 NA	29	static const char lowpan_frags_cache_name[] = "lowpan-frags";
d4ad4d22 NA	30
7240cdec AA	31	static struct inet_frags lowpan_frags;
7240cdec AA	32
254c5dbe PO	33	static int lowpan_frag_reasm(struct lowpan_frag_queue fq, struct sk_buff skb,
254c5dbe PO	34	struct sk_buff prev, struct net_device ldev);
7240cdec	35
36c77782	36	static void lowpan_frag_init(struct inet_frag_queue q, const void a)
7240cdec	37	{
648700f7	38	const struct frag_lowpan_compare_key *key = a;
7240cdec	39
648700f7 ED	40	BUILD_BUG_ON(sizeof(*key) > sizeof(q->key));
648700f7 ED	41	memcpy(&q->key, key, sizeof(*key));
7240cdec	42	}
7240cdec	43
78802011	44	static void lowpan_frag_expire(struct timer_list *t)
7240cdec	45	{
78802011	46	struct inet_frag_queue *frag = from_timer(frag, t, timer);
7240cdec	47	struct frag_queue *fq;
7240cdec	48
78802011	49	fq = container_of(frag, struct frag_queue, q);
7240cdec	50
17794326 FW	51	spin_lock(&fq->q.lock);
17794326 FW	52
06aa8b8a	53	if (fq->q.flags & INET_FRAG_COMPLETE)
17794326 FW	54	goto out;
17794326 FW	55
093ba729	56	inet_frag_kill(&fq->q);
17794326 FW	57	out:
17794326 FW	58	spin_unlock(&fq->q.lock);
093ba729	59	inet_frag_put(&fq->q);
7240cdec AA	60	}
	61
	62	static inline struct lowpan_frag_queue *
72a5e6bb	63	fq_find(struct net net, const struct lowpan_802154_cb cb,
ae531b94 PB	64	const struct ieee802154_addr *src,
ae531b94 PB	65	const struct ieee802154_addr *dst)
7240cdec	66	{
599018a7 LR	67	struct netns_ieee802154_lowpan *ieee802154_lowpan =
599018a7 LR	68	net_ieee802154_lowpan(net);
f18fa5de	69	struct frag_lowpan_compare_key key = {};
648700f7	70	struct inet_frag_queue *q;
7240cdec	71
f18fa5de AA	72	key.tag = cb->d_tag;
	73	key.d_size = cb->d_size;
	74	key.src = *src;
	75	key.dst = *dst;
	76
4907abc6	77	q = inet_frag_find(ieee802154_lowpan->fqdir, &key);
2d44ed22	78	if (!q)
7240cdec	79	return NULL;
2d44ed22	80
7240cdec AA	81	return container_of(q, struct lowpan_frag_queue, q);
	82	}
	83
	84	static int lowpan_frag_queue(struct lowpan_frag_queue *fq,
72a5e6bb	85	struct sk_buff *skb, u8 frag_type)
7240cdec	86	{
254c5dbe	87	struct sk_buff *prev_tail;
f4606583	88	struct net_device *ldev;
254c5dbe PO	89	int end, offset, err;
	90
	91	/* inet_frag_queue_* functions use skb->cb; see struct ipfrag_skb_cb
	92	* in inet_fragment.c
	93	*/
	94	BUILD_BUG_ON(sizeof(struct lowpan_802154_cb) > sizeof(struct inet_skb_parm));
	95	BUILD_BUG_ON(sizeof(struct lowpan_802154_cb) > sizeof(struct inet6_skb_parm));
7240cdec	96
06aa8b8a	97	if (fq->q.flags & INET_FRAG_COMPLETE)
7240cdec AA	98	goto err;
7240cdec AA	99
72a5e6bb AA	100	offset = lowpan_802154_cb(skb)->d_offset << 3;
72a5e6bb AA	101	end = lowpan_802154_cb(skb)->d_size;
7240cdec AA	102
	103	/* Is this the final fragment? */
	104	if (offset + skb->len == end) {
	105	/* If we already have some bits beyond end
	106	* or have different end, the segment is corrupted.
	107	*/
	108	if (end < fq->q.len \|\|
06aa8b8a	109	((fq->q.flags & INET_FRAG_LAST_IN) && end != fq->q.len))
7240cdec	110	goto err;
06aa8b8a	111	fq->q.flags \|= INET_FRAG_LAST_IN;
7240cdec AA	112	fq->q.len = end;
	113	} else {
	114	if (end > fq->q.len) {
	115	/* Some bits beyond end -> corruption. */
06aa8b8a	116	if (fq->q.flags & INET_FRAG_LAST_IN)
7240cdec AA	117	goto err;
	118	fq->q.len = end;
	119	}
	120	}
	121
f4606583 AA	122	ldev = skb->dev;
f4606583 AA	123	if (ldev)
7240cdec	124	skb->dev = NULL;
254c5dbe PO	125	barrier();
	126
	127	prev_tail = fq->q.fragments_tail;
	128	err = inet_frag_queue_insert(&fq->q, skb, offset, end);
	129	if (err)
	130	goto err;
7240cdec AA	131
7240cdec AA	132	fq->q.stamp = skb->tstamp;
72a5e6bb	133	if (frag_type == LOWPAN_DISPATCH_FRAG1)
06aa8b8a	134	fq->q.flags \|= INET_FRAG_FIRST_IN;
72a5e6bb AA	135
72a5e6bb AA	136	fq->q.meat += skb->len;
6ce3b4dc	137	add_frag_mem_limit(fq->q.fqdir, skb->truesize);
7240cdec	138
06aa8b8a	139	if (fq->q.flags == (INET_FRAG_FIRST_IN \| INET_FRAG_LAST_IN) &&
7240cdec AA	140	fq->q.meat == fq->q.len) {
	141	int res;
	142	unsigned long orefdst = skb->_skb_refdst;
	143
	144	skb->_skb_refdst = 0UL;
254c5dbe	145	res = lowpan_frag_reasm(fq, skb, prev_tail, ldev);
7240cdec AA	146	skb->_skb_refdst = orefdst;
	147	return res;
	148	}
254c5dbe	149	skb_dst_drop(skb);
7240cdec	150
7240cdec AA	151	return -1;
	152	err:
	153	kfree_skb(skb);
	154	return -1;
	155	}
	156
	157	/* Check if this packet is complete.
7240cdec AA	158	*
	159	* It is called with locked fq, and caller must check that
	160	* queue is eligible for reassembly i.e. it is not COMPLETE,
	161	* the last and the first frames arrived and all the bits are here.
	162	*/
254c5dbe PO	163	static int lowpan_frag_reasm(struct lowpan_frag_queue fq, struct sk_buff skb,
254c5dbe PO	164	struct sk_buff prev_tail, struct net_device ldev)
7240cdec	165	{
254c5dbe	166	void *reasm_data;
7240cdec	167
093ba729	168	inet_frag_kill(&fq->q);
7240cdec	169
254c5dbe PO	170	reasm_data = inet_frag_reasm_prepare(&fq->q, skb, prev_tail);
254c5dbe PO	171	if (!reasm_data)
7240cdec	172	goto out_oom;
891584f4	173	inet_frag_reasm_finish(&fq->q, skb, reasm_data, false);
7240cdec	174
254c5dbe PO	175	skb->dev = ldev;
254c5dbe PO	176	skb->tstamp = fq->q.stamp;
254c5dbe	177	fq->q.rb_fragments = RB_ROOT;
7240cdec	178	fq->q.fragments_tail = NULL;
254c5dbe	179	fq->q.last_run_head = NULL;
7240cdec AA	180
	181	return 1;
	182	out_oom:
	183	net_dbg_ratelimited("lowpan_frag_reasm: no memory for reassembly\n");
	184	return -1;
	185	}
	186
72a5e6bb AA	187	static int lowpan_frag_rx_handlers_result(struct sk_buff *skb,
	188	lowpan_rx_result res)
	189	{
	190	switch (res) {
	191	case RX_QUEUED:
	192	return NET_RX_SUCCESS;
	193	case RX_CONTINUE:
	194	/* nobody cared about this packet */
	195	net_warn_ratelimited("%s: received unknown dispatch\n",
	196	__func__);
	197
df561f66	198	fallthrough;
72a5e6bb AA	199	default:
	200	/* all others failure */
	201	return NET_RX_DROP;
	202	}
	203	}
	204
	205	static lowpan_rx_result lowpan_frag_rx_h_iphc(struct sk_buff *skb)
	206	{
	207	int ret;
	208
	209	if (!lowpan_is_iphc(*skb_network_header(skb)))
	210	return RX_CONTINUE;
	211
	212	ret = lowpan_iphc_decompress(skb);
	213	if (ret < 0)
	214	return RX_DROP;
	215
	216	return RX_QUEUED;
	217	}
	218
	219	static int lowpan_invoke_frag_rx_handlers(struct sk_buff *skb)
	220	{
	221	lowpan_rx_result res;
	222
	223	#define CALL_RXH(rxh) \
	224	do { \
	225	res = rxh(skb); \
	226	if (res != RX_CONTINUE) \
	227	goto rxh_next; \
	228	} while (0)
	229
	230	/* likely at first */
	231	CALL_RXH(lowpan_frag_rx_h_iphc);
	232	CALL_RXH(lowpan_rx_h_ipv6);
	233
	234	rxh_next:
	235	return lowpan_frag_rx_handlers_result(skb, res);
	236	#undef CALL_RXH
	237	}
	238
	239	#define LOWPAN_FRAG_DGRAM_SIZE_HIGH_MASK 0x07
	240	#define LOWPAN_FRAG_DGRAM_SIZE_HIGH_SHIFT 8
	241
	242	static int lowpan_get_cb(struct sk_buff *skb, u8 frag_type,
	243	struct lowpan_802154_cb *cb)
7240cdec AA	244	{
7240cdec AA	245	bool fail;
72a5e6bb	246	u8 high = 0, low = 0;
f870b8c6	247	__be16 d_tag = 0;
7240cdec	248
72a5e6bb	249	fail = lowpan_fetch_skb(skb, &high, 1);
7240cdec	250	fail \|= lowpan_fetch_skb(skb, &low, 1);
72a5e6bb AA	251	/* remove the dispatch value and use first three bits as high value
	252	* for the datagram size
	253	*/
	254	cb->d_size = (high & LOWPAN_FRAG_DGRAM_SIZE_HIGH_MASK) <<
	255	LOWPAN_FRAG_DGRAM_SIZE_HIGH_SHIFT \| low;
f870b8c6	256	fail \|= lowpan_fetch_skb(skb, &d_tag, 2);
72a5e6bb	257	cb->d_tag = ntohs(d_tag);
7240cdec AA	258
7240cdec AA	259	if (frag_type == LOWPAN_DISPATCH_FRAGN) {
72a5e6bb	260	fail \|= lowpan_fetch_skb(skb, &cb->d_offset, 1);
7240cdec AA	261	} else {
7240cdec AA	262	skb_reset_network_header(skb);
72a5e6bb AA	263	cb->d_offset = 0;
	264	/* check if datagram_size has ipv6hdr on FRAG1 */
	265	fail \|= cb->d_size < sizeof(struct ipv6hdr);
	266	/* check if we can dereference the dispatch value */
	267	fail \|= !skb->len;
7240cdec AA	268	}
	269
	270	if (unlikely(fail))
	271	return -EIO;
	272
	273	return 0;
	274	}
	275
72a5e6bb	276	int lowpan_frag_rcv(struct sk_buff *skb, u8 frag_type)
7240cdec AA	277	{
	278	struct lowpan_frag_queue *fq;
	279	struct net *net = dev_net(skb->dev);
72a5e6bb	280	struct lowpan_802154_cb *cb = lowpan_802154_cb(skb);
f18fa5de	281	struct ieee802154_hdr hdr = {};
7240cdec AA	282	int err;
7240cdec AA	283
72a5e6bb AA	284	if (ieee802154_hdr_peek_addrs(skb, &hdr) < 0)
72a5e6bb AA	285	goto err;
ae531b94	286
72a5e6bb	287	err = lowpan_get_cb(skb, frag_type, cb);
7240cdec AA	288	if (err < 0)
	289	goto err;
	290
72a5e6bb AA	291	if (frag_type == LOWPAN_DISPATCH_FRAG1) {
	292	err = lowpan_invoke_frag_rx_handlers(skb);
	293	if (err == NET_RX_DROP)
	294	goto err;
	295	}
	296
	297	if (cb->d_size > IPV6_MIN_MTU) {
6697dabe	298	net_warn_ratelimited("lowpan_frag_rcv: datagram size exceeds MTU\n");
7240cdec	299	goto err;
6697dabe	300	}
7240cdec	301
72a5e6bb	302	fq = fq_find(net, cb, &hdr.source, &hdr.dest);
7240cdec AA	303	if (fq != NULL) {
7240cdec AA	304	int ret;
4710d806	305
7240cdec AA	306	spin_lock(&fq->q.lock);
	307	ret = lowpan_frag_queue(fq, skb, frag_type);
	308	spin_unlock(&fq->q.lock);
	309
093ba729	310	inet_frag_put(&fq->q);
7240cdec AA	311	return ret;
	312	}
	313
	314	err:
	315	kfree_skb(skb);
	316	return -1;
	317	}
7240cdec AA	318
7240cdec AA	319	#ifdef CONFIG_SYSCTL
1bab4c75	320
7240cdec AA	321	static struct ctl_table lowpan_frags_ns_ctl_table[] = {
	322	{
	323	.procname = "6lowpanfrag_high_thresh",
3e67f106	324	.maxlen = sizeof(unsigned long),
7240cdec	325	.mode = 0644,
3e67f106	326	.proc_handler = proc_doulongvec_minmax,
7240cdec AA	327	},
	328	{
	329	.procname = "6lowpanfrag_low_thresh",
3e67f106	330	.maxlen = sizeof(unsigned long),
7240cdec	331	.mode = 0644,
3e67f106	332	.proc_handler = proc_doulongvec_minmax,
7240cdec AA	333	},
	334	{
	335	.procname = "6lowpanfrag_time",
7240cdec AA	336	.maxlen = sizeof(int),
	337	.mode = 0644,
	338	.proc_handler = proc_dointvec_jiffies,
	339	},
7240cdec AA	340	{ }
	341	};
	342
e3a57d18 FW	343	/* secret interval has been deprecated */
e3a57d18 FW	344	static int lowpan_frags_secret_interval_unused;
7240cdec AA	345	static struct ctl_table lowpan_frags_ctl_table[] = {
	346	{
	347	.procname = "6lowpanfrag_secret_interval",
e3a57d18	348	.data = &lowpan_frags_secret_interval_unused,
7240cdec AA	349	.maxlen = sizeof(int),
	350	.mode = 0644,
	351	.proc_handler = proc_dointvec_jiffies,
	352	},
	353	{ }
	354	};
	355
	356	static int __net_init lowpan_frags_ns_sysctl_register(struct net *net)
	357	{
	358	struct ctl_table *table;
	359	struct ctl_table_header *hdr;
599018a7 LR	360	struct netns_ieee802154_lowpan *ieee802154_lowpan =
599018a7 LR	361	net_ieee802154_lowpan(net);
7240cdec AA	362
	363	table = lowpan_frags_ns_ctl_table;
	364	if (!net_eq(net, &init_net)) {
	365	table = kmemdup(table, sizeof(lowpan_frags_ns_ctl_table),
	366	GFP_KERNEL);
	367	if (table == NULL)
	368	goto err_alloc;
	369
7240cdec AA	370	/* Don't export sysctls to unprivileged users */
	371	if (net->user_ns != &init_user_ns)
	372	table[0].procname = NULL;
	373	}
	374
4907abc6 ED	375	table[0].data = &ieee802154_lowpan->fqdir->high_thresh;
	376	table[0].extra1 = &ieee802154_lowpan->fqdir->low_thresh;
	377	table[1].data = &ieee802154_lowpan->fqdir->low_thresh;
	378	table[1].extra2 = &ieee802154_lowpan->fqdir->high_thresh;
	379	table[2].data = &ieee802154_lowpan->fqdir->timeout;
d2dfd435	380
7240cdec AA	381	hdr = register_net_sysctl(net, "net/ieee802154/6lowpan", table);
	382	if (hdr == NULL)
	383	goto err_reg;
	384
599018a7	385	ieee802154_lowpan->sysctl.frags_hdr = hdr;
7240cdec AA	386	return 0;
	387
	388	err_reg:
	389	if (!net_eq(net, &init_net))
	390	kfree(table);
	391	err_alloc:
	392	return -ENOMEM;
	393	}
	394
	395	static void __net_exit lowpan_frags_ns_sysctl_unregister(struct net *net)
	396	{
	397	struct ctl_table *table;
599018a7 LR	398	struct netns_ieee802154_lowpan *ieee802154_lowpan =
599018a7 LR	399	net_ieee802154_lowpan(net);
7240cdec	400
599018a7 LR	401	table = ieee802154_lowpan->sysctl.frags_hdr->ctl_table_arg;
599018a7 LR	402	unregister_net_sysctl_table(ieee802154_lowpan->sysctl.frags_hdr);
7240cdec AA	403	if (!net_eq(net, &init_net))
	404	kfree(table);
	405	}
	406
	407	static struct ctl_table_header *lowpan_ctl_header;
	408
3243acd3	409	static int __init lowpan_frags_sysctl_register(void)
7240cdec AA	410	{
	411	lowpan_ctl_header = register_net_sysctl(&init_net,
	412	"net/ieee802154/6lowpan",
	413	lowpan_frags_ctl_table);
	414	return lowpan_ctl_header == NULL ? -ENOMEM : 0;
	415	}
	416
	417	static void lowpan_frags_sysctl_unregister(void)
	418	{
	419	unregister_net_sysctl_table(lowpan_ctl_header);
	420	}
	421	#else
f0a0c1ce	422	static inline int lowpan_frags_ns_sysctl_register(struct net *net)
7240cdec AA	423	{
	424	return 0;
	425	}
	426
	427	static inline void lowpan_frags_ns_sysctl_unregister(struct net *net)
	428	{
	429	}
	430
f0a0c1ce	431	static inline int __init lowpan_frags_sysctl_register(void)
7240cdec AA	432	{
	433	return 0;
	434	}
	435
	436	static inline void lowpan_frags_sysctl_unregister(void)
	437	{
	438	}
	439	#endif
	440
	441	static int __net_init lowpan_frags_init_net(struct net *net)
	442	{
599018a7 LR	443	struct netns_ieee802154_lowpan *ieee802154_lowpan =
599018a7 LR	444	net_ieee802154_lowpan(net);
787bea77	445	int res;
7240cdec	446
599018a7	447
a39aca67	448	res = fqdir_init(&ieee802154_lowpan->fqdir, &lowpan_frags, net);
787bea77 ED	449	if (res < 0)
787bea77 ED	450	return res;
4907abc6 ED	451
	452	ieee802154_lowpan->fqdir->high_thresh = IPV6_FRAG_HIGH_THRESH;
	453	ieee802154_lowpan->fqdir->low_thresh = IPV6_FRAG_LOW_THRESH;
	454	ieee802154_lowpan->fqdir->timeout = IPV6_FRAG_TIMEOUT;
	455
787bea77 ED	456	res = lowpan_frags_ns_sysctl_register(net);
787bea77 ED	457	if (res < 0)
4907abc6	458	fqdir_exit(ieee802154_lowpan->fqdir);
787bea77	459	return res;
7240cdec AA	460	}
7240cdec AA	461
d5dd8879 ED	462	static void __net_exit lowpan_frags_pre_exit_net(struct net *net)
	463	{
	464	struct netns_ieee802154_lowpan *ieee802154_lowpan =
	465	net_ieee802154_lowpan(net);
	466
	467	fqdir_pre_exit(ieee802154_lowpan->fqdir);
	468	}
	469
7240cdec AA	470	static void __net_exit lowpan_frags_exit_net(struct net *net)
7240cdec AA	471	{
599018a7 LR	472	struct netns_ieee802154_lowpan *ieee802154_lowpan =
	473	net_ieee802154_lowpan(net);
	474
7240cdec	475	lowpan_frags_ns_sysctl_unregister(net);
4907abc6	476	fqdir_exit(ieee802154_lowpan->fqdir);
7240cdec AA	477	}
	478
	479	static struct pernet_operations lowpan_frags_ops = {
d5dd8879 ED	480	.init = lowpan_frags_init_net,
	481	.pre_exit = lowpan_frags_pre_exit_net,
	482	.exit = lowpan_frags_exit_net,
7240cdec AA	483	};
7240cdec AA	484
648700f7 ED	485	static u32 lowpan_key_hashfn(const void *data, u32 len, u32 seed)
	486	{
	487	return jhash2(data,
	488	sizeof(struct frag_lowpan_compare_key) / sizeof(u32), seed);
	489	}
	490
	491	static u32 lowpan_obj_hashfn(const void *data, u32 len, u32 seed)
	492	{
	493	const struct inet_frag_queue *fq = data;
	494
	495	return jhash2((const u32 *)&fq->key,
	496	sizeof(struct frag_lowpan_compare_key) / sizeof(u32), seed);
	497	}
	498
	499	static int lowpan_obj_cmpfn(struct rhashtable_compare_arg arg, const void ptr)
	500	{
	501	const struct frag_lowpan_compare_key *key = arg->key;
	502	const struct inet_frag_queue *fq = ptr;
	503
	504	return !!memcmp(&fq->key, key, sizeof(*key));
	505	}
	506
	507	static const struct rhashtable_params lowpan_rhash_params = {
	508	.head_offset = offsetof(struct inet_frag_queue, node),
	509	.hashfn = lowpan_key_hashfn,
	510	.obj_hashfn = lowpan_obj_hashfn,
	511	.obj_cmpfn = lowpan_obj_cmpfn,
	512	.automatic_shrinking = true,
	513	};
	514
7240cdec AA	515	int __init lowpan_net_frag_init(void)
	516	{
	517	int ret;
	518
7240cdec AA	519	lowpan_frags.constructor = lowpan_frag_init;
7240cdec AA	520	lowpan_frags.destructor = NULL;
7240cdec	521	lowpan_frags.qsize = sizeof(struct frag_queue);
7240cdec	522	lowpan_frags.frag_expire = lowpan_frag_expire;
d4ad4d22	523	lowpan_frags.frags_cache_name = lowpan_frags_cache_name;
648700f7	524	lowpan_frags.rhash_params = lowpan_rhash_params;
d4ad4d22 NA	525	ret = inet_frags_init(&lowpan_frags);
d4ad4d22 NA	526	if (ret)
807f1844	527	goto out;
37147652	528
807f1844 ED	529	ret = lowpan_frags_sysctl_register();
	530	if (ret)
	531	goto err_sysctl;
	532
	533	ret = register_pernet_subsys(&lowpan_frags_ops);
	534	if (ret)
	535	goto err_pernet;
	536	out:
37147652	537	return ret;
7240cdec AA	538	err_pernet:
7240cdec AA	539	lowpan_frags_sysctl_unregister();
807f1844 ED	540	err_sysctl:
807f1844 ED	541	inet_frags_fini(&lowpan_frags);
7240cdec AA	542	return ret;
	543	}
	544
	545	void lowpan_net_frag_exit(void)
	546	{
7240cdec AA	547	lowpan_frags_sysctl_unregister();
7240cdec AA	548	unregister_pernet_subsys(&lowpan_frags_ops);
ae7352d3	549	inet_frags_fini(&lowpan_frags);
7240cdec	550	}