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Commit 72a5e6bb authored by Alexander Aring's avatar Alexander Aring Committed by Marcel Holtmann
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ieee820154: 6lowpan: dispatch evaluation rework 



This patch complete reworks the evaluation of 6lowpan dispatch value by
introducing a receive handler mechanism for each dispatch value.

A list of changes:

 - Doing uncompression on-the-fly when FRAG1 is received, this require
   some special handling for 802.15.4 lltype in generic 6lowpan branch
   for setting the payload length correct.
 - Fix dispatch mask for fragmentation.
 - Add IPv6 dispatch evaluation for FRAG1.
 - Add skb_unshare for dispatch which might manipulate the skb data
   buffer.

Cc: Jukka Rissanen <jukka.rissanen@linux.intel.com>
Reviewed-by: default avatarStefan Schmidt <stefan@osg.samsung.com>
Signed-off-by: default avatarAlexander Aring <alex.aring@gmail.com>
Signed-off-by: default avatarMarcel Holtmann <marcel@holtmann.org>
parent f801cf40

include/net/6lowpan.h

+25 −6
Original line number Diff line number Diff line
@@ -127,12 +127,18 @@ 
	 (((a)[7]) == 0xFF))



#define LOWPAN_DISPATCH_IPV6		0x41 /* 01000001 = 65 */

#define LOWPAN_DISPATCH_HC1	0x42 /* 01000010 = 66 */

#define LOWPAN_DISPATCH_IPHC		0x60 /* 011xxxxx = ... */

#define LOWPAN_DISPATCH_FRAG1	0xc0 /* 11000xxx */

#define LOWPAN_DISPATCH_FRAGN	0xe0 /* 11100xxx */

#define LOWPAN_DISPATCH_IPHC_MASK	0xe0



#define LOWPAN_DISPATCH_MASK	0xf8 /* 11111000 */

static inline bool lowpan_is_ipv6(u8 dispatch)

{

	return dispatch == LOWPAN_DISPATCH_IPV6;

}



static inline bool lowpan_is_iphc(u8 dispatch)

{

	return (dispatch & LOWPAN_DISPATCH_IPHC_MASK) == LOWPAN_DISPATCH_IPHC;

}



#define LOWPAN_FRAG_TIMEOUT	(HZ * 60)	/* time-out 60 sec */
@@ -218,6 +224,19 @@ struct lowpan_priv *lowpan_priv(const struct net_device *dev) 
	return netdev_priv(dev);

}



struct lowpan_802154_cb {

	u16 d_tag;

	unsigned int d_size;

	u8 d_offset;

};



static inline

struct lowpan_802154_cb *lowpan_802154_cb(const struct sk_buff *skb)

{

	BUILD_BUG_ON(sizeof(struct lowpan_802154_cb) > sizeof(skb->cb));

	return (struct lowpan_802154_cb *)skb->cb;

}



#ifdef DEBUG

/* print data in line */

static inline void raw_dump_inline(const char *caller, char *msg,

net/6lowpan/iphc.c

+12 −1
Original line number Diff line number Diff line
@@ -366,7 +366,18 @@ lowpan_header_decompress(struct sk_buff *skb, struct net_device *dev, 
			return err;

	}



	switch (lowpan_priv(dev)->lltype) {

	case LOWPAN_LLTYPE_IEEE802154:

		if (lowpan_802154_cb(skb)->d_size)

			hdr.payload_len = htons(lowpan_802154_cb(skb)->d_size -

						sizeof(struct ipv6hdr));

		else

			hdr.payload_len = htons(skb->len);

		break;

	default:

		hdr.payload_len = htons(skb->len);

		break;

	}



	pr_debug("skb headroom size = %d, data length = %d\n",

		 skb_headroom(skb), skb->len);

net/6lowpan/nhc_udp.c

+12 −1
Original line number Diff line number Diff line
@@ -71,7 +71,18 @@ static int udp_uncompress(struct sk_buff *skb, size_t needed) 
	 * here, we obtain the hint from the remaining size of the

	 * frame

	 */

	switch (lowpan_priv(skb->dev)->lltype) {

	case LOWPAN_LLTYPE_IEEE802154:

		if (lowpan_802154_cb(skb)->d_size)

			uh.len = htons(lowpan_802154_cb(skb)->d_size -

				       sizeof(struct ipv6hdr));

		else

			uh.len = htons(skb->len + sizeof(struct udphdr));

		break;

	default:

		uh.len = htons(skb->len + sizeof(struct udphdr));

		break;

	}

	pr_debug("uncompressed UDP length: src = %d", ntohs(uh.len));



	/* replace the compressed UDP head by the uncompressed UDP

net/ieee802154/6lowpan/6lowpan_i.h

+12 −0
Original line number Diff line number Diff line
@@ -7,6 +7,15 @@ 
#include <net/inet_frag.h>

#include <net/6lowpan.h>



typedef unsigned __bitwise__ lowpan_rx_result;

#define RX_CONTINUE		((__force lowpan_rx_result) 0u)

#define RX_DROP_UNUSABLE	((__force lowpan_rx_result) 1u)

#define RX_DROP			((__force lowpan_rx_result) 2u)

#define RX_QUEUED		((__force lowpan_rx_result) 3u)



#define LOWPAN_DISPATCH_FRAG1           0xc0

#define LOWPAN_DISPATCH_FRAGN           0xe0



struct lowpan_create_arg {

	u16 tag;

	u16 d_size;
@@ -62,4 +71,7 @@ int lowpan_header_create(struct sk_buff *skb, struct net_device *dev, 
			 const void *_saddr, unsigned int len);

netdev_tx_t lowpan_xmit(struct sk_buff *skb, struct net_device *dev);



int lowpan_iphc_decompress(struct sk_buff *skb);

lowpan_rx_result lowpan_rx_h_ipv6(struct sk_buff *skb);



#endif /* __IEEE802154_6LOWPAN_I_H__ */

net/ieee802154/6lowpan/reassembly.c

+100 −42
Original line number Diff line number Diff line
@@ -32,17 +32,6 @@ 


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



struct lowpan_frag_info {

	u16 d_tag;

	u16 d_size;

	u8 d_offset;

};



static struct lowpan_frag_info *lowpan_cb(struct sk_buff *skb)

{

	return (struct lowpan_frag_info *)skb->cb;

}



static struct inet_frags lowpan_frags;



static int lowpan_frag_reasm(struct lowpan_frag_queue *fq,
@@ -111,7 +100,7 @@ out: 
}



static inline struct lowpan_frag_queue *

fq_find(struct net *net, const struct lowpan_frag_info *frag_info,

fq_find(struct net *net, const struct lowpan_802154_cb *cb,

	const struct ieee802154_addr *src,

	const struct ieee802154_addr *dst)

{
@@ -121,12 +110,12 @@ fq_find(struct net *net, const struct lowpan_frag_info *frag_info, 
	struct netns_ieee802154_lowpan *ieee802154_lowpan =

		net_ieee802154_lowpan(net);



	arg.tag = frag_info->d_tag;

	arg.d_size = frag_info->d_size;

	arg.tag = cb->d_tag;

	arg.d_size = cb->d_size;

	arg.src = src;

	arg.dst = dst;



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

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



	q = inet_frag_find(&ieee802154_lowpan->frags,

			   &lowpan_frags, &arg, hash);
@@ -138,7 +127,7 @@ fq_find(struct net *net, const struct lowpan_frag_info *frag_info, 
}



static int lowpan_frag_queue(struct lowpan_frag_queue *fq,

			     struct sk_buff *skb, const u8 frag_type)

			     struct sk_buff *skb, u8 frag_type)

{

	struct sk_buff *prev, *next;

	struct net_device *ldev;
@@ -147,8 +136,8 @@ static int lowpan_frag_queue(struct lowpan_frag_queue *fq, 
	if (fq->q.flags & INET_FRAG_COMPLETE)

		goto err;



	offset = lowpan_cb(skb)->d_offset << 3;

	end = lowpan_cb(skb)->d_size;

	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) {
@@ -174,13 +163,16 @@ static int lowpan_frag_queue(struct lowpan_frag_queue *fq, 
	 * this fragment, right?

	 */

	prev = fq->q.fragments_tail;

	if (!prev || lowpan_cb(prev)->d_offset < lowpan_cb(skb)->d_offset) {

	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_cb(next)->d_offset >= lowpan_cb(skb)->d_offset)

		if (lowpan_802154_cb(next)->d_offset >=

		    lowpan_802154_cb(skb)->d_offset)

			break;	/* bingo! */

		prev = next;

	}
@@ -200,13 +192,10 @@ found: 
		skb->dev = NULL;



	fq->q.stamp = skb->tstamp;

	if (frag_type == LOWPAN_DISPATCH_FRAG1) {

		/* Calculate uncomp. 6lowpan header to estimate full size */

		fq->q.meat += lowpan_uncompress_size(skb, NULL);

	if (frag_type == LOWPAN_DISPATCH_FRAG1)

		fq->q.flags |= INET_FRAG_FIRST_IN;

	} else {



	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) &&
@@ -325,24 +314,87 @@ out_oom: 
	return -1;

}



static int lowpan_get_frag_info(struct sk_buff *skb, const u8 frag_type,

				struct lowpan_frag_info *frag_info)

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 pattern = 0, low = 0;

	u8 high = 0, low = 0;

	__be16 d_tag = 0;



	fail = lowpan_fetch_skb(skb, &pattern, 1);

	fail = lowpan_fetch_skb(skb, &high, 1);

	fail |= lowpan_fetch_skb(skb, &low, 1);

	frag_info->d_size = (pattern & 7) << 8 | low;

	/* 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);

	frag_info->d_tag = ntohs(d_tag);

	cb->d_tag = ntohs(d_tag);



	if (frag_type == LOWPAN_DISPATCH_FRAGN) {

		fail |= lowpan_fetch_skb(skb, &frag_info->d_offset, 1);

		fail |= lowpan_fetch_skb(skb, &cb->d_offset, 1);

	} else {

		skb_reset_network_header(skb);

		frag_info->d_offset = 0;

		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))
@@ -351,27 +403,33 @@ static int lowpan_get_frag_info(struct sk_buff *skb, const u8 frag_type, 
	return 0;

}



int lowpan_frag_rcv(struct sk_buff *skb, const u8 frag_type)

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_frag_info *frag_info = lowpan_cb(skb);

	struct ieee802154_addr source, dest;

	struct lowpan_802154_cb *cb = lowpan_802154_cb(skb);

	struct ieee802154_hdr hdr;

	int err;



	source = mac_cb(skb)->source;

	dest = mac_cb(skb)->dest;

	if (ieee802154_hdr_peek_addrs(skb, &hdr) < 0)

		goto err;



	err = lowpan_get_frag_info(skb, frag_type, frag_info);

	err = lowpan_get_cb(skb, frag_type, cb);

	if (err < 0)

		goto err;



	if (frag_info->d_size > IPV6_MIN_MTU) {

	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, frag_info, &source, &dest);

	fq = fq_find(net, cb, &hdr.source, &hdr.dest);

	if (fq != NULL) {

		int ret;