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Commit 8df8c56a authored by Jukka Rissanen's avatar Jukka Rissanen Committed by Marcel Holtmann
Browse files

6lowpan: Moving generic compression code into 6lowpan_iphc.c 



Because the IEEE 802154 and Bluetooth share the IP header compression
and uncompression code, the common code is moved to 6lowpan_iphc.c
file.

Signed-off-by: default avatarJukka Rissanen <jukka.rissanen@linux.intel.com>
Acked-by: default avatarAlexander Aring <alex.aring@gmail.com>
Signed-off-by: default avatarMarcel Holtmann <marcel@holtmann.org>
parent 71fb4197

net/ieee802154/6lowpan.c

+35 −718
Original line number Diff line number Diff line
@@ -62,9 +62,6 @@ 


#include "6lowpan.h"



/* TTL uncompression values */

static const u8 lowpan_ttl_values[] = {0, 1, 64, 255};



static LIST_HEAD(lowpan_devices);



/* private device info */
@@ -135,347 +132,14 @@ static inline void lowpan_raw_dump_table(const char *caller, char *msg, 
#endif /* DEBUG */

}



static u8

lowpan_compress_addr_64(u8 **hc06_ptr, u8 shift, const struct in6_addr *ipaddr,

		 const unsigned char *lladdr)

{

	u8 val = 0;



	if (is_addr_mac_addr_based(ipaddr, lladdr))

		val = 3; /* 0-bits */

	else if (lowpan_is_iid_16_bit_compressable(ipaddr)) {

		/* compress IID to 16 bits xxxx::XXXX */

		memcpy(*hc06_ptr, &ipaddr->s6_addr16[7], 2);

		*hc06_ptr += 2;

		val = 2; /* 16-bits */

	} else {

		/* do not compress IID => xxxx::IID */

		memcpy(*hc06_ptr, &ipaddr->s6_addr16[4], 8);

		*hc06_ptr += 8;

		val = 1; /* 64-bits */

	}



	return rol8(val, shift);

}



/*

 * 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)

{

	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;

	}



	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_multicast_daddr(struct sk_buff *skb,

		struct in6_addr *ipaddr,

		const u8 dam)

{

	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;

	}



	if (fail) {

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

		return -EIO;

	}



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

			ipaddr->s6_addr, 16);



	return 0;

}



static void

lowpan_compress_udp_header(u8 **hc06_ptr, struct sk_buff *skb)

{

	struct udphdr *uh = udp_hdr(skb);



	if (((uh->source & LOWPAN_NHC_UDP_4BIT_MASK) ==

				LOWPAN_NHC_UDP_4BIT_PORT) &&

	    ((uh->dest & LOWPAN_NHC_UDP_4BIT_MASK) ==

				LOWPAN_NHC_UDP_4BIT_PORT)) {

		pr_debug("UDP header: both ports compression to 4 bits\n");

		**hc06_ptr = LOWPAN_NHC_UDP_CS_P_11;

		**(hc06_ptr + 1) = /* subtraction is faster */

		   (u8)((uh->dest - LOWPAN_NHC_UDP_4BIT_PORT) +

		       ((uh->source & LOWPAN_NHC_UDP_4BIT_PORT) << 4));

		*hc06_ptr += 2;

	} else if ((uh->dest & LOWPAN_NHC_UDP_8BIT_MASK) ==

			LOWPAN_NHC_UDP_8BIT_PORT) {

		pr_debug("UDP header: remove 8 bits of dest\n");

		**hc06_ptr = LOWPAN_NHC_UDP_CS_P_01;

		memcpy(*hc06_ptr + 1, &uh->source, 2);

		**(hc06_ptr + 3) = (u8)(uh->dest - LOWPAN_NHC_UDP_8BIT_PORT);

		*hc06_ptr += 4;

	} else if ((uh->source & LOWPAN_NHC_UDP_8BIT_MASK) ==

			LOWPAN_NHC_UDP_8BIT_PORT) {

		pr_debug("UDP header: remove 8 bits of source\n");

		**hc06_ptr = LOWPAN_NHC_UDP_CS_P_10;

		memcpy(*hc06_ptr + 1, &uh->dest, 2);

		**(hc06_ptr + 3) = (u8)(uh->source - LOWPAN_NHC_UDP_8BIT_PORT);

		*hc06_ptr += 4;

	} else {

		pr_debug("UDP header: can't compress\n");

		**hc06_ptr = LOWPAN_NHC_UDP_CS_P_00;

		memcpy(*hc06_ptr + 1, &uh->source, 2);

		memcpy(*hc06_ptr + 3, &uh->dest, 2);

		*hc06_ptr += 5;

	}



	/* checksum is always inline */

	memcpy(*hc06_ptr, &uh->check, 2);

	*hc06_ptr += 2;



	/* skip the UDP header */

	skb_pull(skb, sizeof(struct udphdr));

}



static inline int lowpan_fetch_skb_u8(struct sk_buff *skb, u8 *val)

{

	if (unlikely(!pskb_may_pull(skb, 1)))

		return -EINVAL;



	*val = skb->data[0];

	skb_pull(skb, 1);



	return 0;

}



static inline int lowpan_fetch_skb_u16(struct sk_buff *skb, u16 *val)

{

	if (unlikely(!pskb_may_pull(skb, 2)))

		return -EINVAL;



	*val = (skb->data[0] << 8) | skb->data[1];

	skb_pull(skb, 2);



	return 0;

}



static int

lowpan_uncompress_udp_header(struct sk_buff *skb, struct udphdr *uh)

{

	u8 tmp;



	if (!uh)

		goto err;



	if (lowpan_fetch_skb_u8(skb, &tmp))

		goto err;



	if ((tmp & LOWPAN_NHC_UDP_MASK) == LOWPAN_NHC_UDP_ID) {

		pr_debug("UDP header uncompression\n");

		switch (tmp & LOWPAN_NHC_UDP_CS_P_11) {

		case LOWPAN_NHC_UDP_CS_P_00:

			memcpy(&uh->source, &skb->data[0], 2);

			memcpy(&uh->dest, &skb->data[2], 2);

			skb_pull(skb, 4);

			break;

		case LOWPAN_NHC_UDP_CS_P_01:

			memcpy(&uh->source, &skb->data[0], 2);

			uh->dest =

			   skb->data[2] + LOWPAN_NHC_UDP_8BIT_PORT;

			skb_pull(skb, 3);

			break;

		case LOWPAN_NHC_UDP_CS_P_10:

			uh->source = skb->data[0] + LOWPAN_NHC_UDP_8BIT_PORT;

			memcpy(&uh->dest, &skb->data[1], 2);

			skb_pull(skb, 3);

			break;

		case LOWPAN_NHC_UDP_CS_P_11:

			uh->source =

			   LOWPAN_NHC_UDP_4BIT_PORT + (skb->data[0] >> 4);

			uh->dest =

			   LOWPAN_NHC_UDP_4BIT_PORT + (skb->data[0] & 0x0f);

			skb_pull(skb, 1);

			break;

		default:

			pr_debug("ERROR: unknown UDP format\n");

			goto err;

		}



		pr_debug("uncompressed UDP ports: src = %d, dst = %d\n",

			 uh->source, uh->dest);



		/* copy checksum */

		memcpy(&uh->check, &skb->data[0], 2);

		skb_pull(skb, 2);



		/*

		 * UDP lenght needs to be infered from the lower layers

		 * here, we obtain the hint from the remaining size of the

		 * frame

		 */

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

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

	} else {

		pr_debug("ERROR: unsupported NH format\n");

		goto err;

	}



	return 0;

err:

	return -EINVAL;

}



static int lowpan_header_create(struct sk_buff *skb,

			   struct net_device *dev,

			   unsigned short type, const void *_daddr,

			   const void *_saddr, unsigned int len)

{

	u8 tmp, iphc0, iphc1, *hc06_ptr;

	struct ipv6hdr *hdr;

	const u8 *saddr = _saddr;

	const u8 *daddr = _daddr;

	u8 head[100];

	struct ieee802154_addr sa, da;



	/* TODO:
@@ -485,181 +149,14 @@ static int lowpan_header_create(struct sk_buff *skb, 
		return 0;



	hdr = ipv6_hdr(skb);

	hc06_ptr = head + 2;



	pr_debug("IPv6 header dump:\n\tversion = %d\n\tlength  = %d\n"

		 "\tnexthdr = 0x%02x\n\thop_lim = %d\n", hdr->version,

		 ntohs(hdr->payload_len), hdr->nexthdr, hdr->hop_limit);



	lowpan_raw_dump_table(__func__, "raw skb network header dump",

		skb_network_header(skb), sizeof(struct ipv6hdr));



	if (!saddr)

		saddr = dev->dev_addr;



	lowpan_raw_dump_inline(__func__, "saddr", (unsigned char *)saddr, 8);



	/*

	 * As we copy some bit-length fields, in the IPHC encoding bytes,

	 * we sometimes use |=

	 * If the field is 0, and the current bit value in memory is 1,

	 * this does not work. We therefore reset the IPHC encoding here

	 */

	iphc0 = LOWPAN_DISPATCH_IPHC;

	iphc1 = 0;



	/* TODO: context lookup */



	lowpan_raw_dump_inline(__func__, "daddr", (unsigned char *)daddr, 8);



	/*

	 * Traffic class, flow label

	 * If flow label is 0, compress it. If traffic class is 0, compress it

	 * We have to process both in the same time as the offset of traffic

	 * class depends on the presence of version and flow label

	 */



	/* hc06 format of TC is ECN | DSCP , original one is DSCP | ECN */

	tmp = (hdr->priority << 4) | (hdr->flow_lbl[0] >> 4);

	tmp = ((tmp & 0x03) << 6) | (tmp >> 2);



	if (((hdr->flow_lbl[0] & 0x0F) == 0) &&

	     (hdr->flow_lbl[1] == 0) && (hdr->flow_lbl[2] == 0)) {

		/* flow label can be compressed */

		iphc0 |= LOWPAN_IPHC_FL_C;

		if ((hdr->priority == 0) &&

		   ((hdr->flow_lbl[0] & 0xF0) == 0)) {

			/* compress (elide) all */

			iphc0 |= LOWPAN_IPHC_TC_C;

		} else {

			/* compress only the flow label */

			*hc06_ptr = tmp;

			hc06_ptr += 1;

		}

	} else {

		/* Flow label cannot be compressed */

		if ((hdr->priority == 0) &&

		   ((hdr->flow_lbl[0] & 0xF0) == 0)) {

			/* compress only traffic class */

			iphc0 |= LOWPAN_IPHC_TC_C;

			*hc06_ptr = (tmp & 0xc0) | (hdr->flow_lbl[0] & 0x0F);

			memcpy(hc06_ptr + 1, &hdr->flow_lbl[1], 2);

			hc06_ptr += 3;

		} else {

			/* compress nothing */

			memcpy(hc06_ptr, &hdr, 4);

			/* replace the top byte with new ECN | DSCP format */

			*hc06_ptr = tmp;

			hc06_ptr += 4;

		}

	}



	/* NOTE: payload length is always compressed */



	/* Next Header is compress if UDP */

	if (hdr->nexthdr == UIP_PROTO_UDP)

		iphc0 |= LOWPAN_IPHC_NH_C;



	if ((iphc0 & LOWPAN_IPHC_NH_C) == 0) {

		*hc06_ptr = hdr->nexthdr;

		hc06_ptr += 1;

	}



	/*

	 * Hop limit

	 * if 1:   compress, encoding is 01

	 * if 64:  compress, encoding is 10

	 * if 255: compress, encoding is 11

	 * else do not compress

	 */

	switch (hdr->hop_limit) {

	case 1:

		iphc0 |= LOWPAN_IPHC_TTL_1;

		break;

	case 64:

		iphc0 |= LOWPAN_IPHC_TTL_64;

		break;

	case 255:

		iphc0 |= LOWPAN_IPHC_TTL_255;

		break;

	default:

		*hc06_ptr = hdr->hop_limit;

		hc06_ptr += 1;

		break;

	}



	/* source address compression */

	if (is_addr_unspecified(&hdr->saddr)) {

		pr_debug("source address is unspecified, setting SAC\n");

		iphc1 |= LOWPAN_IPHC_SAC;

	/* TODO: context lookup */

	} else if (is_addr_link_local(&hdr->saddr)) {

		pr_debug("source address is link-local\n");

		iphc1 |= lowpan_compress_addr_64(&hc06_ptr,

				LOWPAN_IPHC_SAM_BIT, &hdr->saddr, saddr);

	} else {

		pr_debug("send the full source address\n");

		memcpy(hc06_ptr, &hdr->saddr.s6_addr16[0], 16);

		hc06_ptr += 16;

	}



	/* destination address compression */

	if (is_addr_mcast(&hdr->daddr)) {

		pr_debug("destination address is multicast: ");

		iphc1 |= LOWPAN_IPHC_M;

		if (lowpan_is_mcast_addr_compressable8(&hdr->daddr)) {

			pr_debug("compressed to 1 octet\n");

			iphc1 |= LOWPAN_IPHC_DAM_11;

			/* use last byte */

			*hc06_ptr = hdr->daddr.s6_addr[15];

			hc06_ptr += 1;

		} else if (lowpan_is_mcast_addr_compressable32(&hdr->daddr)) {

			pr_debug("compressed to 4 octets\n");

			iphc1 |= LOWPAN_IPHC_DAM_10;

			/* second byte + the last three */

			*hc06_ptr = hdr->daddr.s6_addr[1];

			memcpy(hc06_ptr + 1, &hdr->daddr.s6_addr[13], 3);

			hc06_ptr += 4;

		} else if (lowpan_is_mcast_addr_compressable48(&hdr->daddr)) {

			pr_debug("compressed to 6 octets\n");

			iphc1 |= LOWPAN_IPHC_DAM_01;

			/* second byte + the last five */

			*hc06_ptr = hdr->daddr.s6_addr[1];

			memcpy(hc06_ptr + 1, &hdr->daddr.s6_addr[11], 5);

			hc06_ptr += 6;

		} else {

			pr_debug("using full address\n");

			iphc1 |= LOWPAN_IPHC_DAM_00;

			memcpy(hc06_ptr, &hdr->daddr.s6_addr[0], 16);

			hc06_ptr += 16;

		}

	} else {

		/* TODO: context lookup */

		if (is_addr_link_local(&hdr->daddr)) {

			pr_debug("dest address is unicast and link-local\n");

			iphc1 |= lowpan_compress_addr_64(&hc06_ptr,

				LOWPAN_IPHC_DAM_BIT, &hdr->daddr, daddr);

		} else {

			pr_debug("dest address is unicast: using full one\n");

			memcpy(hc06_ptr, &hdr->daddr.s6_addr16[0], 16);

			hc06_ptr += 16;

		}

	}



	/* UDP header compression */

	if (hdr->nexthdr == UIP_PROTO_UDP)

		lowpan_compress_udp_header(&hc06_ptr, skb);



	head[0] = iphc0;

	head[1] = iphc1;



	skb_pull(skb, sizeof(struct ipv6hdr));

	skb_reset_transport_header(skb);

	memcpy(skb_push(skb, hc06_ptr - head), head, hc06_ptr - head);

	skb_reset_network_header(skb);



	lowpan_raw_dump_table(__func__, "raw skb data dump", skb->data,

				skb->len);

	lowpan_header_compress(skb, dev, type, daddr, saddr, len);



	/*

	 * NOTE1: I'm still unsure about the fact that compression and WPAN
@@ -671,7 +168,6 @@ static int lowpan_header_create(struct sk_buff *skb, 
	 * from MAC subif of the 'dev' and 'real_dev' network devices, but

	 * this isn't implemented in mainline yet, so currently we assign 0xff

	 */

	{

	mac_cb(skb)->flags = IEEE802154_FC_TYPE_DATA;

	mac_cb(skb)->seq = ieee802154_mlme_ops(dev)->get_dsn(dev);
@@ -701,9 +197,9 @@ static int lowpan_header_create(struct sk_buff *skb, 
	return dev_hard_header(skb, lowpan_dev_info(dev)->real_dev,

			type, (void *)&da, (void *)&sa, skb->len);

}

}



static int lowpan_give_skb_to_devices(struct sk_buff *skb)

static int lowpan_give_skb_to_devices(struct sk_buff *skb,

					struct net_device *dev)

{

	struct lowpan_dev_record *entry;

	struct sk_buff *skb_cp;
@@ -726,31 +222,6 @@ static int lowpan_give_skb_to_devices(struct sk_buff *skb) 
	return stat;

}



static int lowpan_skb_deliver(struct sk_buff *skb, struct ipv6hdr *hdr)

{

	struct sk_buff *new;

	int stat = NET_RX_SUCCESS;



	new = skb_copy_expand(skb, sizeof(struct ipv6hdr), skb_tailroom(skb),

								GFP_ATOMIC);

	kfree_skb(skb);



	if (!new)

		return -ENOMEM;



	skb_push(new, sizeof(struct ipv6hdr));

	skb_copy_to_linear_data(new, hdr, sizeof(struct ipv6hdr));



	new->protocol = htons(ETH_P_IPV6);

	new->pkt_type = PACKET_HOST;



	stat = lowpan_give_skb_to_devices(new);



	kfree_skb(new);



	return stat;

}



static void lowpan_fragment_timer_expired(unsigned long entry_addr)

{

	struct lowpan_fragment *entry = (struct lowpan_fragment *)entry_addr;
@@ -814,13 +285,10 @@ frame_err: 
	return NULL;

}



static int

lowpan_process_data(struct sk_buff *skb)

static int process_data(struct sk_buff *skb)

{

	struct ipv6hdr hdr = {};

	u8 tmp, iphc0, iphc1, num_context = 0;

	u8 iphc0, iphc1;

	const struct ieee802154_addr *_saddr, *_daddr;

	int err;



	lowpan_raw_dump_table(__func__, "raw skb data dump", skb->data,

				skb->len);
@@ -925,162 +393,11 @@ lowpan_process_data(struct sk_buff *skb) 
	_saddr = &mac_cb(skb)->sa;

	_daddr = &mac_cb(skb)->da;



	pr_debug("iphc0 = %02x, iphc1 = %02x\n", iphc0, iphc1);



	/* another if the CID flag is set */

	if (iphc1 & LOWPAN_IPHC_CID) {

		pr_debug("CID flag is set, increase header with one\n");

		if (lowpan_fetch_skb_u8(skb, &num_context))

			goto drop;

	}



	hdr.version = 6;



	/* Traffic Class and Flow Label */

	switch ((iphc0 & LOWPAN_IPHC_TF) >> 3) {

	/*

	 * Traffic Class and FLow Label carried in-line

	 * ECN + DSCP + 4-bit Pad + Flow Label (4 bytes)

	 */

	case 0: /* 00b */

		if (lowpan_fetch_skb_u8(skb, &tmp))

			goto drop;



		memcpy(&hdr.flow_lbl, &skb->data[0], 3);

		skb_pull(skb, 3);

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

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

					(hdr.flow_lbl[0] & 0x0f);

		break;

	/*

	 * Traffic class carried in-line

	 * ECN + DSCP (1 byte), Flow Label is elided

	 */

	case 2: /* 10b */

		if (lowpan_fetch_skb_u8(skb, &tmp))

			goto drop;



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

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

		break;

	/*

	 * Flow Label carried in-line

	 * ECN + 2-bit Pad + Flow Label (3 bytes), DSCP is elided

	 */

	case 1: /* 01b */

		if (lowpan_fetch_skb_u8(skb, &tmp))

			goto drop;



		hdr.flow_lbl[0] = (skb->data[0] & 0x0F) | ((tmp >> 2) & 0x30);

		memcpy(&hdr.flow_lbl[1], &skb->data[0], 2);

		skb_pull(skb, 2);

		break;

	/* Traffic Class and Flow Label are elided */

	case 3: /* 11b */

		break;

	default:

		break;

	}



	/* Next Header */

	if ((iphc0 & LOWPAN_IPHC_NH_C) == 0) {

		/* Next header is carried inline */

		if (lowpan_fetch_skb_u8(skb, &(hdr.nexthdr)))

			goto drop;



		pr_debug("NH flag is set, next header carried inline: %02x\n",

			 hdr.nexthdr);

	}



	/* Hop Limit */

	if ((iphc0 & 0x03) != LOWPAN_IPHC_TTL_I)

		hdr.hop_limit = lowpan_ttl_values[iphc0 & 0x03];

	else {

		if (lowpan_fetch_skb_u8(skb, &(hdr.hop_limit)))

			goto drop;

	}



	/* 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, tmp, _saddr);

	}



	/* Check on error of previous branch */

	if (err)

		goto drop;



	/* Extract DAM to the tmp variable */

	tmp = ((iphc1 & LOWPAN_IPHC_DAM_11) >> LOWPAN_IPHC_DAM_BIT) & 0x03;



	/* check for Multicast Compression */

	if (iphc1 & LOWPAN_IPHC_M) {

		if (iphc1 & LOWPAN_IPHC_DAC) {

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

			/* TODO: implement this */

		} else {

			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, tmp, _daddr);

		if (err)

			goto drop;

	}



	/* UDP data uncompression */

	if (iphc0 & LOWPAN_IPHC_NH_C) {

		struct udphdr uh;

		struct sk_buff *new;

		if (lowpan_uncompress_udp_header(skb, &uh))

			goto drop;



		/*

		 * replace the compressed UDP head by the uncompressed UDP

		 * header

		 */

		new = skb_copy_expand(skb, sizeof(struct udphdr),

				      skb_tailroom(skb), GFP_ATOMIC);

		kfree_skb(skb);



		if (!new)

			return -ENOMEM;



		skb = new;



		skb_push(skb, sizeof(struct udphdr));

		skb_copy_to_linear_data(skb, &uh, sizeof(struct udphdr));



		lowpan_raw_dump_table(__func__, "raw UDP header dump",

				      (u8 *)&uh, sizeof(uh));



		hdr.nexthdr = UIP_PROTO_UDP;

	}



	/* Not fragmented package */

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



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

		 skb_headroom(skb), skb->len);



	pr_debug("IPv6 header dump:\n\tversion = %d\n\tlength  = %d\n\t"

		 "nexthdr = 0x%02x\n\thop_lim = %d\n", hdr.version,

		 ntohs(hdr.payload_len), hdr.nexthdr, hdr.hop_limit);



	lowpan_raw_dump_table(__func__, "raw header dump", (u8 *)&hdr,

							sizeof(hdr));

	return lowpan_skb_deliver(skb, &hdr);

	return lowpan_process_data(skb, skb->dev, (u8 *)_saddr->hwaddr,

				_saddr->addr_type, IEEE802154_ADDR_LEN,

				(u8 *)_daddr->hwaddr, _daddr->addr_type,

				IEEE802154_ADDR_LEN, iphc0, iphc1,

				lowpan_give_skb_to_devices);



unlock_and_drop:

	spin_unlock_bh(&flist_lock);
@@ -1316,7 +633,7 @@ static int lowpan_rcv(struct sk_buff *skb, struct net_device *dev, 
		/* Pull off the 1-byte of 6lowpan header. */

		skb_pull(local_skb, 1);



		lowpan_give_skb_to_devices(local_skb);

		lowpan_give_skb_to_devices(local_skb, NULL);



		kfree_skb(local_skb);

		kfree_skb(skb);
@@ -1328,7 +645,7 @@ static int lowpan_rcv(struct sk_buff *skb, struct net_device *dev, 
			local_skb = skb_clone(skb, GFP_ATOMIC);

			if (!local_skb)

				goto drop;

			lowpan_process_data(local_skb);

			process_data(local_skb);



			kfree_skb(skb);

			break;

net/ieee802154/6lowpan.h

+32 −0
Original line number Diff line number Diff line
@@ -232,6 +232,28 @@ 
					dest = 16 bit inline */

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



static inline int lowpan_fetch_skb_u8(struct sk_buff *skb, u8 *val)

{

	if (unlikely(!pskb_may_pull(skb, 1)))

		return -EINVAL;



	*val = skb->data[0];

	skb_pull(skb, 1);



	return 0;

}



static inline int lowpan_fetch_skb_u16(struct sk_buff *skb, u16 *val)

{

	if (unlikely(!pskb_may_pull(skb, 2)))

		return -EINVAL;



	*val = (skb->data[0] << 8) | skb->data[1];

	skb_pull(skb, 2);



	return 0;

}



static inline bool lowpan_fetch_skb(struct sk_buff *skb,

		void *data, const unsigned int len)

{
@@ -244,4 +266,14 @@ static inline bool lowpan_fetch_skb(struct sk_buff *skb, 
	return false;

}



typedef int (*skb_delivery_cb)(struct sk_buff *skb, struct net_device *dev);



int lowpan_process_data(struct sk_buff *skb, struct net_device *dev,

		const u8 *saddr, const u8 saddr_type, const u8 saddr_len,

		const u8 *daddr, const u8 daddr_type, const u8 daddr_len,

		u8 iphc0, u8 iphc1, skb_delivery_cb skb_deliver);

int lowpan_header_compress(struct sk_buff *skb, struct net_device *dev,

			unsigned short type, const void *_daddr,

			const void *_saddr, unsigned int len);



#endif /* __6LOWPAN_H__ */