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Commit 15ec80f5 authored by David S. Miller's avatar David S. Miller
Browse files

Merge branch '6lowpan' 



Alexander Aring says:

====================
6lowpan: address uncompression fixes

The current implementation to uncompress addresses in a 6lowpan header
is completely broken.

This patch series fixes the parsing of addresses in a 6lowpan header.
It contains a major rewrite of the uncompress address function to parse
the address in a correct way.

Tested with the ravenusbstick(contiki 6LoWPAN stack) and beaglebone
(linux 6LoWPAN Stack) on the other side. The linux side contains all
possible addresses for the uncompression cases. Then I type a ping6 for
each case and lookup in wireshark and dmesg the correct reconstruction.
====================

Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parents 4cffa13d 65d892c8

net/ieee802154/6lowpan.c

+187 −99
Original line number Diff line number Diff line
@@ -67,39 +67,6 @@ static const u8 lowpan_ttl_values[] = {0, 1, 64, 255}; 


static LIST_HEAD(lowpan_devices);



/*

 * Uncompression of linklocal:

 *   0 -> 16 bytes from packet

 *   1 -> 2  bytes from prefix - bunch of zeroes and 8 from packet

 *   2 -> 2  bytes from prefix - zeroes + 2 from packet

 *   3 -> 2  bytes from prefix - infer 8 bytes from lladdr

 *

 *  NOTE: => the uncompress function does change 0xf to 0x10

 *  NOTE: 0x00 => no-autoconfig => unspecified

 */

static const u8 lowpan_unc_llconf[] = {0x0f, 0x28, 0x22, 0x20};



/*

 * Uncompression of ctx-based:

 *   0 -> 0 bits  from packet [unspecified / reserved]

 *   1 -> 8 bytes from prefix - bunch of zeroes and 8 from packet

 *   2 -> 8 bytes from prefix - zeroes + 2 from packet

 *   3 -> 8 bytes from prefix - infer 8 bytes from lladdr

 */

static const u8 lowpan_unc_ctxconf[] = {0x00, 0x88, 0x82, 0x80};



/*

 * Uncompression of ctx-base

 *   0 -> 0 bits from packet

 *   1 -> 2 bytes from prefix - bunch of zeroes 5 from packet

 *   2 -> 2 bytes from prefix - zeroes + 3 from packet

 *   3 -> 2 bytes from prefix - infer 1 bytes from lladdr

 */

static const u8 lowpan_unc_mxconf[] = {0x0f, 0x25, 0x23, 0x21};



/* Link local prefix */

static const u8 lowpan_llprefix[] = {0xfe, 0x80};



/* private device info */

struct lowpan_dev_info {

	struct net_device	*real_dev; /* real WPAN device ptr */
@@ -191,55 +158,177 @@ lowpan_compress_addr_64(u8 **hc06_ptr, u8 shift, const struct in6_addr *ipaddr, 
	return rol8(val, shift);

}



static void

lowpan_uip_ds6_set_addr_iid(struct in6_addr *ipaddr, unsigned char *lladdr)

/*

 * Uncompress address function for source and

 * destination address(non-multicast).

 *

 * address_mode is sam value or dam value.

 */

static int

lowpan_uncompress_addr(struct sk_buff *skb,

		struct in6_addr *ipaddr,

		const u8 address_mode,

		const struct ieee802154_addr *lladdr)

{

	memcpy(&ipaddr->s6_addr[8], lladdr, IEEE802154_ADDR_LEN);

	/* second bit-flip (Universe/Local) is done according RFC2464 */

	bool fail;



	switch (address_mode) {

	case LOWPAN_IPHC_ADDR_00:

		/* for global link addresses */

		fail = lowpan_fetch_skb(skb, ipaddr->s6_addr, 16);

		break;

	case LOWPAN_IPHC_ADDR_01:

		/* fe:80::XXXX:XXXX:XXXX:XXXX */

		ipaddr->s6_addr[0] = 0xFE;

		ipaddr->s6_addr[1] = 0x80;

		fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[8], 8);

		break;

	case LOWPAN_IPHC_ADDR_02:

		/* fe:80::ff:fe00:XXXX */

		ipaddr->s6_addr[0] = 0xFE;

		ipaddr->s6_addr[1] = 0x80;

		ipaddr->s6_addr[11] = 0xFF;

		ipaddr->s6_addr[12] = 0xFE;

		fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[14], 2);

		break;

	case LOWPAN_IPHC_ADDR_03:

		fail = false;

		switch (lladdr->addr_type) {

		case IEEE802154_ADDR_LONG:

			/* fe:80::XXXX:XXXX:XXXX:XXXX

			 *        \_________________/

			 *              hwaddr

			 */

			ipaddr->s6_addr[0] = 0xFE;

			ipaddr->s6_addr[1] = 0x80;

			memcpy(&ipaddr->s6_addr[8], lladdr->hwaddr,

					IEEE802154_ADDR_LEN);

			/* second bit-flip (Universe/Local)

			 * is done according RFC2464

			 */

			ipaddr->s6_addr[8] ^= 0x02;

			break;

		case IEEE802154_ADDR_SHORT:

			/* fe:80::ff:fe00:XXXX

			 *		  \__/

			 *	       short_addr

			 *

			 * Universe/Local bit is zero.

			 */

			ipaddr->s6_addr[0] = 0xFE;

			ipaddr->s6_addr[1] = 0x80;

			ipaddr->s6_addr[11] = 0xFF;

			ipaddr->s6_addr[12] = 0xFE;

			ipaddr->s6_addr16[7] = htons(lladdr->short_addr);

			break;

		default:

			pr_debug("Invalid addr_type set\n");

			return -EINVAL;

		}

		break;

	default:

		pr_debug("Invalid address mode value: 0x%x\n", address_mode);

		return -EINVAL;

	}



/*

 * Uncompress addresses based on a prefix and a postfix with zeroes in

 * between. If the postfix is zero in length it will use the link address

 * to configure the IP address (autoconf style).

 * pref_post_count takes a byte where the first nibble specify prefix count

 * and the second postfix count (NOTE: 15/0xf => 16 bytes copy).

	if (fail) {

		pr_debug("Failed to fetch skb data\n");

		return -EIO;

	}



	lowpan_raw_dump_inline(NULL, "Reconstructed ipv6 addr is:\n",

			ipaddr->s6_addr, 16);



	return 0;

}



/* Uncompress address function for source context

 * based address(non-multicast).

 */

static int

lowpan_uncompress_context_based_src_addr(struct sk_buff *skb,

		struct in6_addr *ipaddr,

		const u8 sam)

{

	switch (sam) {

	case LOWPAN_IPHC_ADDR_00:

		/* unspec address ::

		 * Do nothing, address is already ::

		 */

		break;

	case LOWPAN_IPHC_ADDR_01:

		/* TODO */

	case LOWPAN_IPHC_ADDR_02:

		/* TODO */

	case LOWPAN_IPHC_ADDR_03:

		/* TODO */

		netdev_warn(skb->dev, "SAM value 0x%x not supported\n", sam);

		return -EINVAL;

	default:

		pr_debug("Invalid sam value: 0x%x\n", sam);

		return -EINVAL;

	}



	lowpan_raw_dump_inline(NULL,

			"Reconstructed context based ipv6 src addr is:\n",

			ipaddr->s6_addr, 16);



	return 0;

}



/* Uncompress function for multicast destination address,

 * when M bit is set.

 */

static int

lowpan_uncompress_addr(struct sk_buff *skb, struct in6_addr *ipaddr,

	u8 const *prefix, u8 pref_post_count, unsigned char *lladdr)

lowpan_uncompress_multicast_daddr(struct sk_buff *skb,

		struct in6_addr *ipaddr,

		const u8 dam)

{

	u8 prefcount = pref_post_count >> 4;

	u8 postcount = pref_post_count & 0x0f;



	/* full nibble 15 => 16 */

	prefcount = (prefcount == 15 ? 16 : prefcount);

	postcount = (postcount == 15 ? 16 : postcount);



	if (lladdr)

		lowpan_raw_dump_inline(__func__, "linklocal address",

						lladdr,	IEEE802154_ADDR_LEN);

	if (prefcount > 0)

		memcpy(ipaddr, prefix, prefcount);



	if (prefcount + postcount < 16)

		memset(&ipaddr->s6_addr[prefcount], 0,

					16 - (prefcount + postcount));



	if (postcount > 0) {

		memcpy(&ipaddr->s6_addr[16 - postcount], skb->data, postcount);

		skb_pull(skb, postcount);

	} else if (prefcount > 0) {

		if (lladdr == NULL)

	bool fail;



	switch (dam) {

	case LOWPAN_IPHC_DAM_00:

		/* 00:  128 bits.  The full address

		 * is carried in-line.

		 */

		fail = lowpan_fetch_skb(skb, ipaddr->s6_addr, 16);

		break;

	case LOWPAN_IPHC_DAM_01:

		/* 01:  48 bits.  The address takes

		 * the form ffXX::00XX:XXXX:XXXX.

		 */

		ipaddr->s6_addr[0] = 0xFF;

		fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[1], 1);

		fail |= lowpan_fetch_skb(skb, &ipaddr->s6_addr[11], 5);

		break;

	case LOWPAN_IPHC_DAM_10:

		/* 10:  32 bits.  The address takes

		 * the form ffXX::00XX:XXXX.

		 */

		ipaddr->s6_addr[0] = 0xFF;

		fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[1], 1);

		fail |= lowpan_fetch_skb(skb, &ipaddr->s6_addr[13], 3);

		break;

	case LOWPAN_IPHC_DAM_11:

		/* 11:  8 bits.  The address takes

		 * the form ff02::00XX.

		 */

		ipaddr->s6_addr[0] = 0xFF;

		ipaddr->s6_addr[1] = 0x02;

		fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[15], 1);

		break;

	default:

		pr_debug("DAM value has a wrong value: 0x%x\n", dam);

		return -EINVAL;

	}



		/* no IID based configuration if no prefix and no data */

		lowpan_uip_ds6_set_addr_iid(ipaddr, lladdr);

	if (fail) {

		pr_debug("Failed to fetch skb data\n");

		return -EIO;

	}



	pr_debug("uncompressing %d + %d => ", prefcount, postcount);

	lowpan_raw_dump_inline(NULL, NULL, ipaddr->s6_addr, 16);

	lowpan_raw_dump_inline(NULL, "Reconstructed ipv6 multicast addr is:\n",

			ipaddr->s6_addr, 16);



	return 0;

}
@@ -702,6 +791,12 @@ lowpan_alloc_new_frame(struct sk_buff *skb, u16 len, u16 tag) 
	skb_reserve(frame->skb, sizeof(struct ipv6hdr));

	skb_put(frame->skb, frame->length);



	/* copy the first control block to keep a

	 * trace of the link-layer addresses in case

	 * of a link-local compressed address

	 */

	memcpy(frame->skb->cb, skb->cb, sizeof(skb->cb));



	init_timer(&frame->timer);

	/* time out is the same as for ipv6 - 60 sec */

	frame->timer.expires = jiffies + LOWPAN_FRAG_TIMEOUT;
@@ -723,9 +818,9 @@ lowpan_alloc_new_frame(struct sk_buff *skb, u16 len, u16 tag) 
static int

lowpan_process_data(struct sk_buff *skb)

{

	struct ipv6hdr hdr;

	struct ipv6hdr hdr = {};

	u8 tmp, iphc0, iphc1, num_context = 0;

	u8 *_saddr, *_daddr;

	const struct ieee802154_addr *_saddr, *_daddr;

	int err;



	lowpan_raw_dump_table(__func__, "raw skb data dump", skb->data,
@@ -828,8 +923,8 @@ lowpan_process_data(struct sk_buff *skb) 
	if (lowpan_fetch_skb_u8(skb, &iphc1))

		goto drop;



	_saddr = mac_cb(skb)->sa.hwaddr;

	_daddr = mac_cb(skb)->da.hwaddr;

	_saddr = &mac_cb(skb)->sa;

	_daddr = &mac_cb(skb)->da;



	pr_debug("iphc0 = %02x, iphc1 = %02x\n", iphc0, iphc1);
@@ -868,8 +963,6 @@ lowpan_process_data(struct sk_buff *skb) 


		hdr.priority = ((tmp >> 2) & 0x0f);

		hdr.flow_lbl[0] = ((tmp << 6) & 0xC0) | ((tmp >> 2) & 0x30);

		hdr.flow_lbl[1] = 0;

		hdr.flow_lbl[2] = 0;

		break;

	/*

	 * Flow Label carried in-line
@@ -885,10 +978,6 @@ lowpan_process_data(struct sk_buff *skb) 
		break;

	/* Traffic Class and Flow Label are elided */

	case 3: /* 11b */

		hdr.priority = 0;

		hdr.flow_lbl[0] = 0;

		hdr.flow_lbl[1] = 0;

		hdr.flow_lbl[2] = 0;

		break;

	default:

		break;
@@ -915,10 +1004,18 @@ lowpan_process_data(struct sk_buff *skb) 
	/* Extract SAM to the tmp variable */

	tmp = ((iphc1 & LOWPAN_IPHC_SAM) >> LOWPAN_IPHC_SAM_BIT) & 0x03;



	if (iphc1 & LOWPAN_IPHC_SAC) {

		/* Source address context based uncompression */

		pr_debug("SAC bit is set. Handle context based source address.\n");

		err = lowpan_uncompress_context_based_src_addr(

				skb, &hdr.saddr, tmp);

	} else {

		/* Source address uncompression */

		pr_debug("source address stateless compression\n");

	err = lowpan_uncompress_addr(skb, &hdr.saddr, lowpan_llprefix,

				lowpan_unc_llconf[tmp], skb->data);

		err = lowpan_uncompress_addr(skb, &hdr.saddr, tmp, _saddr);

	}



	/* Check on error of previous branch */

	if (err)

		goto drop;
@@ -931,23 +1028,14 @@ lowpan_process_data(struct sk_buff *skb) 
			pr_debug("dest: context-based mcast compression\n");

			/* TODO: implement this */

		} else {

			u8 prefix[] = {0xff, 0x02};



			pr_debug("dest: non context-based mcast compression\n");

			if (0 < tmp && tmp < 3) {

				if (lowpan_fetch_skb_u8(skb, &prefix[1]))

					goto drop;

			}



			err = lowpan_uncompress_addr(skb, &hdr.daddr, prefix,

					lowpan_unc_mxconf[tmp], NULL);

			err = lowpan_uncompress_multicast_daddr(

					skb, &hdr.daddr, tmp);

			if (err)

				goto drop;

		}

	} else {

		pr_debug("dest: stateless compression\n");

		err = lowpan_uncompress_addr(skb, &hdr.daddr, lowpan_llprefix,

				lowpan_unc_llconf[tmp], skb->data);

		err = lowpan_uncompress_addr(skb, &hdr.daddr, tmp, _daddr);

		if (err)

			goto drop;

	}

net/ieee802154/6lowpan.h

+17 −3
Original line number Diff line number Diff line
@@ -193,10 +193,12 @@ 
/* Values of fields within the IPHC encoding second byte */

#define LOWPAN_IPHC_CID		0x80



#define LOWPAN_IPHC_ADDR_00	0x00

#define LOWPAN_IPHC_ADDR_01	0x01

#define LOWPAN_IPHC_ADDR_02	0x02

#define LOWPAN_IPHC_ADDR_03	0x03



#define LOWPAN_IPHC_SAC		0x40

#define LOWPAN_IPHC_SAM_00	0x00

#define LOWPAN_IPHC_SAM_01	0x10

#define LOWPAN_IPHC_SAM_10	0x20

#define LOWPAN_IPHC_SAM		0x30



#define LOWPAN_IPHC_SAM_BIT	4
@@ -230,4 +232,16 @@ 
					dest = 16 bit inline */

#define LOWPAN_NHC_UDP_CS_P_11	0xF3 /* source & dest = 0xF0B + 4bit inline */



static inline bool lowpan_fetch_skb(struct sk_buff *skb,

		void *data, const unsigned int len)

{

	if (unlikely(!pskb_may_pull(skb, len)))

		return true;



	skb_copy_from_linear_data(skb, data, len);

	skb_pull(skb, len);



	return false;

}



#endif /* __6LOWPAN_H__ */