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Commit 349aa7bc authored by Alexander Aring's avatar Alexander Aring Committed by David S. Miller
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6lowpan: add uncompress header size function 



This patch add a lookup function for uncompressed 6LoWPAN header
size. This is needed to estimate the real size after uncompress the
6LoWPAN header.

Signed-off-by: default avatarAlexander Aring <alex.aring@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 89745c9c

net/ieee802154/6lowpan.h

+113 −0
Original line number Original line Diff line number Diff line
@@ -306,6 +306,119 @@ static inline void lowpan_push_hc_data(u8 **hc_ptr, const void *data, 
	*hc_ptr += len;

	*hc_ptr += len;

}

}





static inline u8 lowpan_addr_mode_size(const u8 addr_mode)

{

	static const u8 addr_sizes[] = {

		[LOWPAN_IPHC_ADDR_00] = 16,

		[LOWPAN_IPHC_ADDR_01] = 8,

		[LOWPAN_IPHC_ADDR_02] = 2,

		[LOWPAN_IPHC_ADDR_03] = 0,

	};

	return addr_sizes[addr_mode];

}



static inline u8 lowpan_next_hdr_size(const u8 h_enc, u16 *uncomp_header)

{

	u8 ret = 1;



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

		*uncomp_header += sizeof(struct udphdr);



		switch (h_enc & LOWPAN_NHC_UDP_CS_P_11) {

		case LOWPAN_NHC_UDP_CS_P_00:

			ret += 4;

			break;

		case LOWPAN_NHC_UDP_CS_P_01:

		case LOWPAN_NHC_UDP_CS_P_10:

			ret += 3;

			break;

		case LOWPAN_NHC_UDP_CS_P_11:

			ret++;

			break;

		default:

			break;

		}



		if (!(h_enc & LOWPAN_NHC_UDP_CS_C))

			ret += 2;

	}



	return ret;

}



/**

 *	lowpan_uncompress_size - returns skb->len size with uncompressed header

 *	@skb: sk_buff with 6lowpan header inside

 *	@datagram_offset: optional to get the datagram_offset value

 *

 *	Returns the skb->len with uncompressed header

 */

static inline u16

lowpan_uncompress_size(const struct sk_buff *skb, u16 *dgram_offset)

{

	u16 ret = 2, uncomp_header = sizeof(struct ipv6hdr);

	u8 iphc0, iphc1, h_enc;



	iphc0 = skb_network_header(skb)[0];

	iphc1 = skb_network_header(skb)[1];



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

	case 0:

		ret += 4;

		break;

	case 1:

		ret += 3;

		break;

	case 2:

		ret++;

		break;

	default:

		break;

	}



	if (!(iphc0 & LOWPAN_IPHC_NH_C))

		ret++;



	if (!(iphc0 & 0x03))

		ret++;



	ret += lowpan_addr_mode_size((iphc1 & LOWPAN_IPHC_SAM) >>

				     LOWPAN_IPHC_SAM_BIT);



	if (iphc1 & LOWPAN_IPHC_M) {

		switch ((iphc1 & LOWPAN_IPHC_DAM_11) >>

			LOWPAN_IPHC_DAM_BIT) {

		case LOWPAN_IPHC_DAM_00:

			ret += 16;

			break;

		case LOWPAN_IPHC_DAM_01:

			ret += 6;

			break;

		case LOWPAN_IPHC_DAM_10:

			ret += 4;

			break;

		case LOWPAN_IPHC_DAM_11:

			ret++;

			break;

		default:

			break;

		}

	} else {

		ret += lowpan_addr_mode_size((iphc1 & LOWPAN_IPHC_DAM_11) >>

					     LOWPAN_IPHC_DAM_BIT);

	}



	if (iphc0 & LOWPAN_IPHC_NH_C) {

		h_enc = skb_network_header(skb)[ret];

		ret += lowpan_next_hdr_size(h_enc, &uncomp_header);

	}



	if (dgram_offset)

		*dgram_offset = uncomp_header;



	return skb->len + uncomp_header - ret;

}



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

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,

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