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Commit f8b1b5d2 authored by alex.bluesman.smirnov@gmail.com's avatar alex.bluesman.smirnov@gmail.com Committed by David S. Miller
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6LoWPAN: UDP header decompression 



This patch provides possibility to decompress UDP headers.
Derived from Contiki OS.

Signed-off-by: default avatarAlexander Smirnov <alex.bluesman.smirnov@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 3bd5b958

net/ieee802154/6lowpan.c

+60 −1
Original line number Diff line number Diff line
@@ -311,6 +311,62 @@ static u16 lowpan_fetch_skb_u16(struct sk_buff *skb) 
	return ret;

}



static int

lowpan_uncompress_udp_header(struct sk_buff *skb)

{

	struct udphdr *uh = udp_hdr(skb);

	u8 tmp;



	tmp = lowpan_fetch_skb_u8(skb);



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

		pr_debug("(%s): UDP header uncompression\n", __func__);

		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("(%s) ERROR: unknown UDP format\n", __func__);

			goto err;

			break;

		}



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

					__func__, uh->source, uh->dest);



		/* copy checksum */

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

		skb_pull(skb, 2);

	} else {

		pr_debug("(%s): ERROR: unsupported NH format\n", __func__);

		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,
@@ -842,7 +898,10 @@ lowpan_process_data(struct sk_buff *skb) 
			goto drop;

	}



	/* TODO: UDP header parse */

	/* UDP data uncompression */

	if (iphc0 & LOWPAN_IPHC_NH_C)

		if (lowpan_uncompress_udp_header(skb))

			goto drop;



	/* Not fragmented package */

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