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

/*	6LoWPAN fragment reassembly
 *
 *
 *	Authors:
 *	Alexander Aring		<aar@pengutronix.de>
 *
 *	Based on: net/ipv6/reassembly.c
 *
 *	This program is free software; you can redistribute it and/or
 *	modify it under the terms of the GNU General Public License
 *	as published by the Free Software Foundation; either version
 *	2 of the License, or (at your option) any later version.
 */

#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.h>
#include <net/inet_frag.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 *prev, struct net_device *ldev);

static unsigned int lowpan_hash_frag(u16 tag, u16 d_size,
				     const struct ieee802154_addr *saddr,
				     const struct ieee802154_addr *daddr)
{
	net_get_random_once(&lowpan_frags.rnd, sizeof(lowpan_frags.rnd));
	return jhash_3words(ieee802154_addr_hash(saddr),
			    ieee802154_addr_hash(daddr),
			    (__force u32)(tag + (d_size << 16)),
			    lowpan_frags.rnd);
}

static unsigned int lowpan_hashfn(const struct inet_frag_queue *q)
{
	const struct lowpan_frag_queue *fq;

	fq = container_of(q, struct lowpan_frag_queue, q);
	return lowpan_hash_frag(fq->tag, fq->d_size, &fq->saddr, &fq->daddr);
}

static bool lowpan_frag_match(const struct inet_frag_queue *q, const void *a)
{
	const struct lowpan_frag_queue *fq;
	const struct lowpan_create_arg *arg = a;

	fq = container_of(q, struct lowpan_frag_queue, q);
	return	fq->tag == arg->tag && fq->d_size == arg->d_size &&
		ieee802154_addr_equal(&fq->saddr, arg->src) &&
		ieee802154_addr_equal(&fq->daddr, arg->dst);
}

static void lowpan_frag_init(struct inet_frag_queue *q, const void *a)
{
	const struct lowpan_create_arg *arg = a;
	struct lowpan_frag_queue *fq;

	fq = container_of(q, struct lowpan_frag_queue, q);

	fq->tag = arg->tag;
	fq->d_size = arg->d_size;
	fq->saddr = *arg->src;
	fq->daddr = *arg->dst;
}

static void lowpan_frag_expire(unsigned long data)
{
	struct frag_queue *fq;
	struct net *net;

	fq = container_of((struct inet_frag_queue *)data, struct frag_queue, q);
	net = container_of(fq->q.net, struct net, ieee802154_lowpan.frags);

	spin_lock(&fq->q.lock);

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

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

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 inet_frag_queue *q;
	struct lowpan_create_arg arg;
	unsigned int hash;
	struct netns_ieee802154_lowpan *ieee802154_lowpan =
		net_ieee802154_lowpan(net);

	arg.tag = cb->d_tag;
	arg.d_size = cb->d_size;
	arg.src = src;
	arg.dst = dst;

	hash = lowpan_hash_frag(cb->d_tag, cb->d_size, src, dst);

	q = inet_frag_find(&ieee802154_lowpan->frags,
			   &lowpan_frags, &arg, hash);
	if (IS_ERR_OR_NULL(q)) {
		inet_frag_maybe_warn_overflow(q, pr_fmt());
		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, *next;
	struct net_device *ldev;
	int end, offset;

	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;
		}
	}

	/* Find out which fragments are in front and at the back of us
	 * in the chain of fragments so far.  We must know where to put
	 * this fragment, right?
	 */
	prev = fq->q.fragments_tail;
	if (!prev ||
	    lowpan_802154_cb(prev)->d_offset <
	    lowpan_802154_cb(skb)->d_offset) {
		next = NULL;
		goto found;
	}
	prev = NULL;
	for (next = fq->q.fragments; next != NULL; next = next->next) {
		if (lowpan_802154_cb(next)->d_offset >=
		    lowpan_802154_cb(skb)->d_offset)
			break;	/* bingo! */
		prev = next;
	}

found:
	/* Insert this fragment in the chain of fragments. */
	skb->next = next;
	if (!next)
		fq->q.fragments_tail = skb;
	if (prev)
		prev->next = skb;
	else
		fq->q.fragments = skb;

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

	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.net, 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, prev, ldev);
		skb->_skb_refdst = orefdst;
		return res;
	}

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

/*	Check if this packet is complete.
 *	Returns NULL on failure by any reason, and pointer
 *	to current nexthdr field in reassembled frame.
 *
 *	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 *prev,
			     struct net_device *ldev)
{
	struct sk_buff *fp, *head = fq->q.fragments;
	int sum_truesize;

	inet_frag_kill(&fq->q, &lowpan_frags);

	/* Make the one we just received the head. */
	if (prev) {
		head = prev->next;
		fp = skb_clone(head, GFP_ATOMIC);

		if (!fp)
			goto out_oom;

		fp->next = head->next;
		if (!fp->next)
			fq->q.fragments_tail = fp;
		prev->next = fp;

		skb_morph(head, fq->q.fragments);
		head->next = fq->q.fragments->next;

		consume_skb(fq->q.fragments);
		fq->q.fragments = head;
	}

	/* Head of list must not be cloned. */
	if (skb_unclone(head, GFP_ATOMIC))
		goto out_oom;

	/* If the first fragment is fragmented itself, we split
	 * it to two chunks: the first with data and paged part
	 * and the second, holding only fragments.
	 */
	if (skb_has_frag_list(head)) {
		struct sk_buff *clone;
		int i, plen = 0;

		clone = alloc_skb(0, GFP_ATOMIC);
		if (!clone)
			goto out_oom;
		clone->next = head->next;
		head->next = clone;
		skb_shinfo(clone)->frag_list = skb_shinfo(head)->frag_list;
		skb_frag_list_init(head);
		for (i = 0; i < skb_shinfo(head)->nr_frags; i++)
			plen += skb_frag_size(&skb_shinfo(head)->frags[i]);
		clone->len = head->data_len - plen;
		clone->data_len = clone->len;
		head->data_len -= clone->len;
		head->len -= clone->len;
		add_frag_mem_limit(fq->q.net, clone->truesize);
	}

	WARN_ON(head == NULL);

	sum_truesize = head->truesize;
	for (fp = head->next; fp;) {
		bool headstolen;
		int delta;
		struct sk_buff *next = fp->next;

		sum_truesize += fp->truesize;
		if (skb_try_coalesce(head, fp, &headstolen, &delta)) {
			kfree_skb_partial(fp, headstolen);
		} else {
			if (!skb_shinfo(head)->frag_list)
				skb_shinfo(head)->frag_list = fp;
			head->data_len += fp->len;
			head->len += fp->len;
			head->truesize += fp->truesize;
		}
		fp = next;
	}
	sub_frag_mem_limit(fq->q.net, sum_truesize);

	head->next = NULL;
	head->dev = ldev;
	head->tstamp = fq->q.stamp;

	fq->q.fragments = NULL;
	fq->q.fragments_tail = 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__);

		/* fall-through */
	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, &lowpan_frags);
		return ret;
	}

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

#ifdef CONFIG_SYSCTL
static int zero;

static struct ctl_table lowpan_frags_ns_ctl_table[] = {
	{
		.procname	= "6lowpanfrag_high_thresh",
		.data		= &init_net.ieee802154_lowpan.frags.high_thresh,
		.maxlen		= sizeof(int),
		.mode		= 0644,
		.proc_handler	= proc_dointvec_minmax,
		.extra1		= &init_net.ieee802154_lowpan.frags.low_thresh
	},
	{
		.procname	= "6lowpanfrag_low_thresh",
		.data		= &init_net.ieee802154_lowpan.frags.low_thresh,
		.maxlen		= sizeof(int),
		.mode		= 0644,
		.proc_handler	= proc_dointvec_minmax,
		.extra1		= &zero,
		.extra2		= &init_net.ieee802154_lowpan.frags.high_thresh
	},
	{
		.procname	= "6lowpanfrag_time",
		.data		= &init_net.ieee802154_lowpan.frags.timeout,
		.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;

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

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

	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;

	ieee802154_lowpan->frags.high_thresh = IPV6_FRAG_HIGH_THRESH;
	ieee802154_lowpan->frags.low_thresh = IPV6_FRAG_LOW_THRESH;
	ieee802154_lowpan->frags.timeout = IPV6_FRAG_TIMEOUT;

	res = inet_frags_init_net(&ieee802154_lowpan->frags);
	if (res)
		return res;
	res = lowpan_frags_ns_sysctl_register(net);
	if (res)
		inet_frags_uninit_net(&ieee802154_lowpan->frags);
	return res;
}

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);
	inet_frags_exit_net(&ieee802154_lowpan->frags, &lowpan_frags);
}

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

int __init lowpan_net_frag_init(void)
{
	int ret;

	ret = lowpan_frags_sysctl_register();
	if (ret)
		return ret;

	ret = register_pernet_subsys(&lowpan_frags_ops);
	if (ret)
		goto err_pernet;

	lowpan_frags.hashfn = lowpan_hashfn;
	lowpan_frags.constructor = lowpan_frag_init;
	lowpan_frags.destructor = NULL;
	lowpan_frags.qsize = sizeof(struct frag_queue);
	lowpan_frags.match = lowpan_frag_match;
	lowpan_frags.frag_expire = lowpan_frag_expire;
	lowpan_frags.frags_cache_name = lowpan_frags_cache_name;
	ret = inet_frags_init(&lowpan_frags);
	if (ret)
		goto err_pernet;

	return ret;
err_pernet:
	lowpan_frags_sysctl_unregister();
	return ret;
}

void lowpan_net_frag_exit(void)
{
	inet_frags_fini(&lowpan_frags);
	lowpan_frags_sysctl_unregister();
	unregister_pernet_subsys(&lowpan_frags_ops);
}
Commit	Line	Data
7240cdec AA	1	/* 6LoWPAN fragment reassembly
	2	*
	3	*
	4	* Authors:
	5	* Alexander Aring <aar@pengutronix.de>
	6	*
	7	* Based on: net/ipv6/reassembly.c
	8	*
	9	* This program is free software; you can redistribute it and/or
	10	* modify it under the terms of the GNU General Public License
	11	* as published by the Free Software Foundation; either version
	12	* 2 of the License, or (at your option) any later version.
	13	*/
	14
	15	#define pr_fmt(fmt) "6LoWPAN: " fmt
	16
	17	#include <linux/net.h>
	18	#include <linux/list.h>
	19	#include <linux/netdevice.h>
	20	#include <linux/random.h>
	21	#include <linux/jhash.h>
	22	#include <linux/skbuff.h>
	23	#include <linux/slab.h>
	24	#include <linux/export.h>
	25
	26	#include <net/ieee802154_netdev.h>
cefc8c8a	27	#include <net/6lowpan.h>
7240cdec AA	28	#include <net/ipv6.h>
	29	#include <net/inet_frag.h>
	30
8691ee59	31	#include "6lowpan_i.h"
7240cdec	32
d4ad4d22 NA	33	static const char lowpan_frags_cache_name[] = "lowpan-frags";
d4ad4d22 NA	34
7240cdec AA	35	static struct inet_frags lowpan_frags;
	36
	37	static int lowpan_frag_reasm(struct lowpan_frag_queue *fq,
f4606583	38	struct sk_buff prev, struct net_device ldev);
7240cdec	39
f870b8c6	40	static unsigned int lowpan_hash_frag(u16 tag, u16 d_size,
ae531b94 PB	41	const struct ieee802154_addr *saddr,
ae531b94 PB	42	const struct ieee802154_addr *daddr)
7240cdec	43	{
7240cdec	44	net_get_random_once(&lowpan_frags.rnd, sizeof(lowpan_frags.rnd));
fb3cfe6e FW	45	return jhash_3words(ieee802154_addr_hash(saddr),
	46	ieee802154_addr_hash(daddr),
	47	(__force u32)(tag + (d_size << 16)),
	48	lowpan_frags.rnd);
7240cdec AA	49	}
7240cdec AA	50
36c77782	51	static unsigned int lowpan_hashfn(const struct inet_frag_queue *q)
7240cdec	52	{
36c77782	53	const struct lowpan_frag_queue *fq;
7240cdec AA	54
	55	fq = container_of(q, struct lowpan_frag_queue, q);
	56	return lowpan_hash_frag(fq->tag, fq->d_size, &fq->saddr, &fq->daddr);
	57	}
	58
36c77782	59	static bool lowpan_frag_match(const struct inet_frag_queue q, const void a)
7240cdec	60	{
36c77782 FW	61	const struct lowpan_frag_queue *fq;
36c77782 FW	62	const struct lowpan_create_arg *arg = a;
7240cdec AA	63
	64	fq = container_of(q, struct lowpan_frag_queue, q);
	65	return fq->tag == arg->tag && fq->d_size == arg->d_size &&
ae531b94 PB	66	ieee802154_addr_equal(&fq->saddr, arg->src) &&
ae531b94 PB	67	ieee802154_addr_equal(&fq->daddr, arg->dst);
7240cdec	68	}
7240cdec	69
36c77782	70	static void lowpan_frag_init(struct inet_frag_queue q, const void a)
7240cdec	71	{
36c77782	72	const struct lowpan_create_arg *arg = a;
7240cdec	73	struct lowpan_frag_queue *fq;
7240cdec AA	74
	75	fq = container_of(q, struct lowpan_frag_queue, q);
	76
	77	fq->tag = arg->tag;
	78	fq->d_size = arg->d_size;
	79	fq->saddr = *arg->src;
	80	fq->daddr = *arg->dst;
	81	}
7240cdec AA	82
	83	static void lowpan_frag_expire(unsigned long data)
	84	{
	85	struct frag_queue *fq;
	86	struct net *net;
	87
	88	fq = container_of((struct inet_frag_queue *)data, struct frag_queue, q);
	89	net = container_of(fq->q.net, struct net, ieee802154_lowpan.frags);
	90
17794326 FW	91	spin_lock(&fq->q.lock);
17794326 FW	92
06aa8b8a	93	if (fq->q.flags & INET_FRAG_COMPLETE)
17794326 FW	94	goto out;
	95
	96	inet_frag_kill(&fq->q, &lowpan_frags);
	97	out:
	98	spin_unlock(&fq->q.lock);
	99	inet_frag_put(&fq->q, &lowpan_frags);
7240cdec AA	100	}
	101
	102	static inline struct lowpan_frag_queue *
72a5e6bb	103	fq_find(struct net net, const struct lowpan_802154_cb cb,
ae531b94 PB	104	const struct ieee802154_addr *src,
ae531b94 PB	105	const struct ieee802154_addr *dst)
7240cdec AA	106	{
	107	struct inet_frag_queue *q;
	108	struct lowpan_create_arg arg;
	109	unsigned int hash;
599018a7 LR	110	struct netns_ieee802154_lowpan *ieee802154_lowpan =
599018a7 LR	111	net_ieee802154_lowpan(net);
7240cdec	112
72a5e6bb AA	113	arg.tag = cb->d_tag;
72a5e6bb AA	114	arg.d_size = cb->d_size;
7240cdec AA	115	arg.src = src;
	116	arg.dst = dst;
	117
72a5e6bb	118	hash = lowpan_hash_frag(cb->d_tag, cb->d_size, src, dst);
7240cdec	119
599018a7	120	q = inet_frag_find(&ieee802154_lowpan->frags,
7240cdec AA	121	&lowpan_frags, &arg, hash);
	122	if (IS_ERR_OR_NULL(q)) {
	123	inet_frag_maybe_warn_overflow(q, pr_fmt());
	124	return NULL;
	125	}
	126	return container_of(q, struct lowpan_frag_queue, q);
	127	}
	128
	129	static int lowpan_frag_queue(struct lowpan_frag_queue *fq,
72a5e6bb	130	struct sk_buff *skb, u8 frag_type)
7240cdec AA	131	{
7240cdec AA	132	struct sk_buff prev, next;
f4606583	133	struct net_device *ldev;
7240cdec AA	134	int end, offset;
7240cdec AA	135
06aa8b8a	136	if (fq->q.flags & INET_FRAG_COMPLETE)
7240cdec AA	137	goto err;
7240cdec AA	138
72a5e6bb AA	139	offset = lowpan_802154_cb(skb)->d_offset << 3;
72a5e6bb AA	140	end = lowpan_802154_cb(skb)->d_size;
7240cdec AA	141
	142	/* Is this the final fragment? */
	143	if (offset + skb->len == end) {
	144	/* If we already have some bits beyond end
	145	* or have different end, the segment is corrupted.
	146	*/
	147	if (end < fq->q.len \|\|
06aa8b8a	148	((fq->q.flags & INET_FRAG_LAST_IN) && end != fq->q.len))
7240cdec	149	goto err;
06aa8b8a	150	fq->q.flags \|= INET_FRAG_LAST_IN;
7240cdec AA	151	fq->q.len = end;
	152	} else {
	153	if (end > fq->q.len) {
	154	/* Some bits beyond end -> corruption. */
06aa8b8a	155	if (fq->q.flags & INET_FRAG_LAST_IN)
7240cdec AA	156	goto err;
	157	fq->q.len = end;
	158	}
	159	}
	160
	161	/* Find out which fragments are in front and at the back of us
	162	* in the chain of fragments so far. We must know where to put
	163	* this fragment, right?
	164	*/
	165	prev = fq->q.fragments_tail;
72a5e6bb AA	166	if (!prev \|\|
	167	lowpan_802154_cb(prev)->d_offset <
	168	lowpan_802154_cb(skb)->d_offset) {
7240cdec AA	169	next = NULL;
	170	goto found;
	171	}
	172	prev = NULL;
	173	for (next = fq->q.fragments; next != NULL; next = next->next) {
72a5e6bb AA	174	if (lowpan_802154_cb(next)->d_offset >=
72a5e6bb AA	175	lowpan_802154_cb(skb)->d_offset)
7240cdec AA	176	break; /* bingo! */
	177	prev = next;
	178	}
	179
	180	found:
	181	/* Insert this fragment in the chain of fragments. */
	182	skb->next = next;
	183	if (!next)
	184	fq->q.fragments_tail = skb;
	185	if (prev)
	186	prev->next = skb;
	187	else
	188	fq->q.fragments = skb;
	189
f4606583 AA	190	ldev = skb->dev;
f4606583 AA	191	if (ldev)
7240cdec AA	192	skb->dev = NULL;
	193
	194	fq->q.stamp = skb->tstamp;
72a5e6bb	195	if (frag_type == LOWPAN_DISPATCH_FRAG1)
06aa8b8a	196	fq->q.flags \|= INET_FRAG_FIRST_IN;
72a5e6bb AA	197
72a5e6bb AA	198	fq->q.meat += skb->len;
0e60d245	199	add_frag_mem_limit(fq->q.net, skb->truesize);
7240cdec	200
06aa8b8a	201	if (fq->q.flags == (INET_FRAG_FIRST_IN \| INET_FRAG_LAST_IN) &&
7240cdec AA	202	fq->q.meat == fq->q.len) {
	203	int res;
	204	unsigned long orefdst = skb->_skb_refdst;
	205
	206	skb->_skb_refdst = 0UL;
f4606583	207	res = lowpan_frag_reasm(fq, prev, ldev);
7240cdec AA	208	skb->_skb_refdst = orefdst;
	209	return res;
	210	}
	211
7240cdec AA	212	return -1;
	213	err:
	214	kfree_skb(skb);
	215	return -1;
	216	}
	217
	218	/* Check if this packet is complete.
	219	* Returns NULL on failure by any reason, and pointer
	220	* to current nexthdr field in reassembled frame.
	221	*
	222	* It is called with locked fq, and caller must check that
	223	* queue is eligible for reassembly i.e. it is not COMPLETE,
	224	* the last and the first frames arrived and all the bits are here.
	225	*/
	226	static int lowpan_frag_reasm(struct lowpan_frag_queue fq, struct sk_buff prev,
f4606583	227	struct net_device *ldev)
7240cdec AA	228	{
	229	struct sk_buff fp, head = fq->q.fragments;
	230	int sum_truesize;
	231
	232	inet_frag_kill(&fq->q, &lowpan_frags);
	233
	234	/* Make the one we just received the head. */
	235	if (prev) {
	236	head = prev->next;
	237	fp = skb_clone(head, GFP_ATOMIC);
	238
	239	if (!fp)
	240	goto out_oom;
	241
	242	fp->next = head->next;
	243	if (!fp->next)
	244	fq->q.fragments_tail = fp;
	245	prev->next = fp;
	246
	247	skb_morph(head, fq->q.fragments);
	248	head->next = fq->q.fragments->next;
	249
	250	consume_skb(fq->q.fragments);
	251	fq->q.fragments = head;
	252	}
	253
	254	/* Head of list must not be cloned. */
	255	if (skb_unclone(head, GFP_ATOMIC))
	256	goto out_oom;
	257
	258	/* If the first fragment is fragmented itself, we split
	259	* it to two chunks: the first with data and paged part
	260	* and the second, holding only fragments.
	261	*/
	262	if (skb_has_frag_list(head)) {
	263	struct sk_buff *clone;
	264	int i, plen = 0;
	265
	266	clone = alloc_skb(0, GFP_ATOMIC);
	267	if (!clone)
	268	goto out_oom;
	269	clone->next = head->next;
	270	head->next = clone;
	271	skb_shinfo(clone)->frag_list = skb_shinfo(head)->frag_list;
	272	skb_frag_list_init(head);
	273	for (i = 0; i < skb_shinfo(head)->nr_frags; i++)
	274	plen += skb_frag_size(&skb_shinfo(head)->frags[i]);
	275	clone->len = head->data_len - plen;
	276	clone->data_len = clone->len;
	277	head->data_len -= clone->len;
	278	head->len -= clone->len;
0e60d245	279	add_frag_mem_limit(fq->q.net, clone->truesize);
7240cdec AA	280	}
	281
	282	WARN_ON(head == NULL);
	283
	284	sum_truesize = head->truesize;
	285	for (fp = head->next; fp;) {
	286	bool headstolen;
	287	int delta;
	288	struct sk_buff *next = fp->next;
	289
	290	sum_truesize += fp->truesize;
	291	if (skb_try_coalesce(head, fp, &headstolen, &delta)) {
	292	kfree_skb_partial(fp, headstolen);
	293	} else {
	294	if (!skb_shinfo(head)->frag_list)
	295	skb_shinfo(head)->frag_list = fp;
	296	head->data_len += fp->len;
	297	head->len += fp->len;
	298	head->truesize += fp->truesize;
	299	}
	300	fp = next;
	301	}
0e60d245	302	sub_frag_mem_limit(fq->q.net, sum_truesize);
7240cdec AA	303
7240cdec AA	304	head->next = NULL;
f4606583	305	head->dev = ldev;
7240cdec AA	306	head->tstamp = fq->q.stamp;
	307
	308	fq->q.fragments = NULL;
	309	fq->q.fragments_tail = NULL;
	310
	311	return 1;
	312	out_oom:
	313	net_dbg_ratelimited("lowpan_frag_reasm: no memory for reassembly\n");
	314	return -1;
	315	}
	316
72a5e6bb AA	317	static int lowpan_frag_rx_handlers_result(struct sk_buff *skb,
	318	lowpan_rx_result res)
	319	{
	320	switch (res) {
	321	case RX_QUEUED:
	322	return NET_RX_SUCCESS;
	323	case RX_CONTINUE:
	324	/* nobody cared about this packet */
	325	net_warn_ratelimited("%s: received unknown dispatch\n",
	326	__func__);
	327
	328	/* fall-through */
	329	default:
	330	/* all others failure */
	331	return NET_RX_DROP;
	332	}
	333	}
	334
	335	static lowpan_rx_result lowpan_frag_rx_h_iphc(struct sk_buff *skb)
	336	{
	337	int ret;
	338
	339	if (!lowpan_is_iphc(*skb_network_header(skb)))
	340	return RX_CONTINUE;
	341
	342	ret = lowpan_iphc_decompress(skb);
	343	if (ret < 0)
	344	return RX_DROP;
	345
	346	return RX_QUEUED;
	347	}
	348
	349	static int lowpan_invoke_frag_rx_handlers(struct sk_buff *skb)
	350	{
	351	lowpan_rx_result res;
	352
	353	#define CALL_RXH(rxh) \
	354	do { \
	355	res = rxh(skb); \
	356	if (res != RX_CONTINUE) \
	357	goto rxh_next; \
	358	} while (0)
	359
	360	/* likely at first */
	361	CALL_RXH(lowpan_frag_rx_h_iphc);
	362	CALL_RXH(lowpan_rx_h_ipv6);
	363
	364	rxh_next:
	365	return lowpan_frag_rx_handlers_result(skb, res);
	366	#undef CALL_RXH
	367	}
	368
	369	#define LOWPAN_FRAG_DGRAM_SIZE_HIGH_MASK 0x07
	370	#define LOWPAN_FRAG_DGRAM_SIZE_HIGH_SHIFT 8
	371
	372	static int lowpan_get_cb(struct sk_buff *skb, u8 frag_type,
	373	struct lowpan_802154_cb *cb)
7240cdec AA	374	{
7240cdec AA	375	bool fail;
72a5e6bb	376	u8 high = 0, low = 0;
f870b8c6	377	__be16 d_tag = 0;
7240cdec	378
72a5e6bb	379	fail = lowpan_fetch_skb(skb, &high, 1);
7240cdec	380	fail \|= lowpan_fetch_skb(skb, &low, 1);
72a5e6bb AA	381	/* remove the dispatch value and use first three bits as high value
	382	* for the datagram size
	383	*/
	384	cb->d_size = (high & LOWPAN_FRAG_DGRAM_SIZE_HIGH_MASK) <<
	385	LOWPAN_FRAG_DGRAM_SIZE_HIGH_SHIFT \| low;
f870b8c6	386	fail \|= lowpan_fetch_skb(skb, &d_tag, 2);
72a5e6bb	387	cb->d_tag = ntohs(d_tag);
7240cdec AA	388
7240cdec AA	389	if (frag_type == LOWPAN_DISPATCH_FRAGN) {
72a5e6bb	390	fail \|= lowpan_fetch_skb(skb, &cb->d_offset, 1);
7240cdec AA	391	} else {
7240cdec AA	392	skb_reset_network_header(skb);
72a5e6bb AA	393	cb->d_offset = 0;
	394	/* check if datagram_size has ipv6hdr on FRAG1 */
	395	fail \|= cb->d_size < sizeof(struct ipv6hdr);
	396	/* check if we can dereference the dispatch value */
	397	fail \|= !skb->len;
7240cdec AA	398	}
	399
	400	if (unlikely(fail))
	401	return -EIO;
	402
	403	return 0;
	404	}
	405
72a5e6bb	406	int lowpan_frag_rcv(struct sk_buff *skb, u8 frag_type)
7240cdec AA	407	{
	408	struct lowpan_frag_queue *fq;
	409	struct net *net = dev_net(skb->dev);
72a5e6bb AA	410	struct lowpan_802154_cb *cb = lowpan_802154_cb(skb);
72a5e6bb AA	411	struct ieee802154_hdr hdr;
7240cdec AA	412	int err;
7240cdec AA	413
72a5e6bb AA	414	if (ieee802154_hdr_peek_addrs(skb, &hdr) < 0)
72a5e6bb AA	415	goto err;
ae531b94	416
72a5e6bb	417	err = lowpan_get_cb(skb, frag_type, cb);
7240cdec AA	418	if (err < 0)
	419	goto err;
	420
72a5e6bb AA	421	if (frag_type == LOWPAN_DISPATCH_FRAG1) {
	422	err = lowpan_invoke_frag_rx_handlers(skb);
	423	if (err == NET_RX_DROP)
	424	goto err;
	425	}
	426
	427	if (cb->d_size > IPV6_MIN_MTU) {
6697dabe	428	net_warn_ratelimited("lowpan_frag_rcv: datagram size exceeds MTU\n");
7240cdec	429	goto err;
6697dabe	430	}
7240cdec	431
72a5e6bb	432	fq = fq_find(net, cb, &hdr.source, &hdr.dest);
7240cdec AA	433	if (fq != NULL) {
7240cdec AA	434	int ret;
4710d806	435
7240cdec AA	436	spin_lock(&fq->q.lock);
	437	ret = lowpan_frag_queue(fq, skb, frag_type);
	438	spin_unlock(&fq->q.lock);
	439
	440	inet_frag_put(&fq->q, &lowpan_frags);
	441	return ret;
	442	}
	443
	444	err:
	445	kfree_skb(skb);
	446	return -1;
	447	}
7240cdec AA	448
7240cdec AA	449	#ifdef CONFIG_SYSCTL
1bab4c75 NA	450	static int zero;
1bab4c75 NA	451
7240cdec AA	452	static struct ctl_table lowpan_frags_ns_ctl_table[] = {
	453	{
	454	.procname = "6lowpanfrag_high_thresh",
	455	.data = &init_net.ieee802154_lowpan.frags.high_thresh,
	456	.maxlen = sizeof(int),
	457	.mode = 0644,
1bab4c75 NA	458	.proc_handler = proc_dointvec_minmax,
1bab4c75 NA	459	.extra1 = &init_net.ieee802154_lowpan.frags.low_thresh
7240cdec AA	460	},
	461	{
	462	.procname = "6lowpanfrag_low_thresh",
	463	.data = &init_net.ieee802154_lowpan.frags.low_thresh,
	464	.maxlen = sizeof(int),
	465	.mode = 0644,
1bab4c75 NA	466	.proc_handler = proc_dointvec_minmax,
	467	.extra1 = &zero,
	468	.extra2 = &init_net.ieee802154_lowpan.frags.high_thresh
7240cdec AA	469	},
	470	{
	471	.procname = "6lowpanfrag_time",
	472	.data = &init_net.ieee802154_lowpan.frags.timeout,
	473	.maxlen = sizeof(int),
	474	.mode = 0644,
	475	.proc_handler = proc_dointvec_jiffies,
	476	},
7240cdec AA	477	{ }
	478	};
	479
e3a57d18 FW	480	/* secret interval has been deprecated */
e3a57d18 FW	481	static int lowpan_frags_secret_interval_unused;
7240cdec AA	482	static struct ctl_table lowpan_frags_ctl_table[] = {
	483	{
	484	.procname = "6lowpanfrag_secret_interval",
e3a57d18	485	.data = &lowpan_frags_secret_interval_unused,
7240cdec AA	486	.maxlen = sizeof(int),
	487	.mode = 0644,
	488	.proc_handler = proc_dointvec_jiffies,
	489	},
	490	{ }
	491	};
	492
	493	static int __net_init lowpan_frags_ns_sysctl_register(struct net *net)
	494	{
	495	struct ctl_table *table;
	496	struct ctl_table_header *hdr;
599018a7 LR	497	struct netns_ieee802154_lowpan *ieee802154_lowpan =
599018a7 LR	498	net_ieee802154_lowpan(net);
7240cdec AA	499
	500	table = lowpan_frags_ns_ctl_table;
	501	if (!net_eq(net, &init_net)) {
	502	table = kmemdup(table, sizeof(lowpan_frags_ns_ctl_table),
	503	GFP_KERNEL);
	504	if (table == NULL)
	505	goto err_alloc;
	506
599018a7	507	table[0].data = &ieee802154_lowpan->frags.high_thresh;
1bab4c75 NA	508	table[0].extra1 = &ieee802154_lowpan->frags.low_thresh;
1bab4c75 NA	509	table[0].extra2 = &init_net.ieee802154_lowpan.frags.high_thresh;
599018a7	510	table[1].data = &ieee802154_lowpan->frags.low_thresh;
1bab4c75	511	table[1].extra2 = &ieee802154_lowpan->frags.high_thresh;
599018a7	512	table[2].data = &ieee802154_lowpan->frags.timeout;
7240cdec AA	513
	514	/* Don't export sysctls to unprivileged users */
	515	if (net->user_ns != &init_user_ns)
	516	table[0].procname = NULL;
	517	}
	518
	519	hdr = register_net_sysctl(net, "net/ieee802154/6lowpan", table);
	520	if (hdr == NULL)
	521	goto err_reg;
	522
599018a7	523	ieee802154_lowpan->sysctl.frags_hdr = hdr;
7240cdec AA	524	return 0;
	525
	526	err_reg:
	527	if (!net_eq(net, &init_net))
	528	kfree(table);
	529	err_alloc:
	530	return -ENOMEM;
	531	}
	532
	533	static void __net_exit lowpan_frags_ns_sysctl_unregister(struct net *net)
	534	{
	535	struct ctl_table *table;
599018a7 LR	536	struct netns_ieee802154_lowpan *ieee802154_lowpan =
599018a7 LR	537	net_ieee802154_lowpan(net);
7240cdec	538
599018a7 LR	539	table = ieee802154_lowpan->sysctl.frags_hdr->ctl_table_arg;
599018a7 LR	540	unregister_net_sysctl_table(ieee802154_lowpan->sysctl.frags_hdr);
7240cdec AA	541	if (!net_eq(net, &init_net))
	542	kfree(table);
	543	}
	544
	545	static struct ctl_table_header *lowpan_ctl_header;
	546
3243acd3	547	static int __init lowpan_frags_sysctl_register(void)
7240cdec AA	548	{
	549	lowpan_ctl_header = register_net_sysctl(&init_net,
	550	"net/ieee802154/6lowpan",
	551	lowpan_frags_ctl_table);
	552	return lowpan_ctl_header == NULL ? -ENOMEM : 0;
	553	}
	554
	555	static void lowpan_frags_sysctl_unregister(void)
	556	{
	557	unregister_net_sysctl_table(lowpan_ctl_header);
	558	}
	559	#else
f0a0c1ce	560	static inline int lowpan_frags_ns_sysctl_register(struct net *net)
7240cdec AA	561	{
	562	return 0;
	563	}
	564
	565	static inline void lowpan_frags_ns_sysctl_unregister(struct net *net)
	566	{
	567	}
	568
f0a0c1ce	569	static inline int __init lowpan_frags_sysctl_register(void)
7240cdec AA	570	{
	571	return 0;
	572	}
	573
	574	static inline void lowpan_frags_sysctl_unregister(void)
	575	{
	576	}
	577	#endif
	578
	579	static int __net_init lowpan_frags_init_net(struct net *net)
	580	{
599018a7 LR	581	struct netns_ieee802154_lowpan *ieee802154_lowpan =
599018a7 LR	582	net_ieee802154_lowpan(net);
1d6119ba	583	int res;
7240cdec	584
599018a7 LR	585	ieee802154_lowpan->frags.high_thresh = IPV6_FRAG_HIGH_THRESH;
	586	ieee802154_lowpan->frags.low_thresh = IPV6_FRAG_LOW_THRESH;
	587	ieee802154_lowpan->frags.timeout = IPV6_FRAG_TIMEOUT;
599018a7	588
1d6119ba ED	589	res = inet_frags_init_net(&ieee802154_lowpan->frags);
	590	if (res)
	591	return res;
	592	res = lowpan_frags_ns_sysctl_register(net);
	593	if (res)
	594	inet_frags_uninit_net(&ieee802154_lowpan->frags);
	595	return res;
7240cdec AA	596	}
	597
	598	static void __net_exit lowpan_frags_exit_net(struct net *net)
	599	{
599018a7 LR	600	struct netns_ieee802154_lowpan *ieee802154_lowpan =
	601	net_ieee802154_lowpan(net);
	602
7240cdec	603	lowpan_frags_ns_sysctl_unregister(net);
599018a7	604	inet_frags_exit_net(&ieee802154_lowpan->frags, &lowpan_frags);
7240cdec AA	605	}
	606
	607	static struct pernet_operations lowpan_frags_ops = {
	608	.init = lowpan_frags_init_net,
	609	.exit = lowpan_frags_exit_net,
	610	};
	611
	612	int __init lowpan_net_frag_init(void)
	613	{
	614	int ret;
	615
	616	ret = lowpan_frags_sysctl_register();
	617	if (ret)
37147652	618	return ret;
7240cdec AA	619
	620	ret = register_pernet_subsys(&lowpan_frags_ops);
	621	if (ret)
	622	goto err_pernet;
	623
	624	lowpan_frags.hashfn = lowpan_hashfn;
	625	lowpan_frags.constructor = lowpan_frag_init;
	626	lowpan_frags.destructor = NULL;
7240cdec AA	627	lowpan_frags.qsize = sizeof(struct frag_queue);
	628	lowpan_frags.match = lowpan_frag_match;
	629	lowpan_frags.frag_expire = lowpan_frag_expire;
d4ad4d22 NA	630	lowpan_frags.frags_cache_name = lowpan_frags_cache_name;
	631	ret = inet_frags_init(&lowpan_frags);
	632	if (ret)
	633	goto err_pernet;
37147652 AA	634
37147652 AA	635	return ret;
7240cdec AA	636	err_pernet:
7240cdec AA	637	lowpan_frags_sysctl_unregister();
7240cdec AA	638	return ret;
	639	}
	640
	641	void lowpan_net_frag_exit(void)
	642	{
	643	inet_frags_fini(&lowpan_frags);
	644	lowpan_frags_sysctl_unregister();
	645	unregister_pernet_subsys(&lowpan_frags_ops);
	646	}