Commit 3bd5b958 authored by alex.bluesman.smirnov@gmail.com's avatar alex.bluesman.smirnov@gmail.com Committed by David S. Miller
Browse files

6LoWPAN: UDP header compression 



This patch adds support for UDP header compression.
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 4d039f68

net/ieee802154/6lowpan.c

+47 −4
Original line number Diff line number Diff line
@@ -246,6 +246,50 @@ lowpan_uncompress_addr(struct sk_buff *skb, struct in6_addr *ipaddr, 
	return 0;

}



static void

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

{

	struct udphdr *uh = udp_hdr(skb);



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



	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("(%s): both ports compression to 4 bits\n", __func__);

		**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("(%s): remove 8 bits of dest\n", __func__);

		**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("(%s): remove 8 bits of source\n", __func__);

		**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("(%s): can't compress header\n", __func__);

		**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;

}



static u8 lowpan_fetch_skb_u8(struct sk_buff *skb)

{

	u8 ret;
@@ -365,8 +409,6 @@ static int lowpan_header_create(struct sk_buff *skb, 
	if (hdr->nexthdr == UIP_PROTO_UDP)

		iphc0 |= LOWPAN_IPHC_NH_C;



/* TODO: next header compression */



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

		*hc06_ptr = hdr->nexthdr;

		hc06_ptr += 1;
@@ -454,8 +496,9 @@ static int lowpan_header_create(struct sk_buff *skb, 
		}

	}



	/* TODO: UDP header compression */

	/* TODO: Next Header compression */

	/* UDP header compression */

	if (hdr->nexthdr == UIP_PROTO_UDP)

		lowpan_compress_udp_header(&hc06_ptr, skb);



	head[0] = iphc0;

	head[1] = iphc1;

net/ieee802154/6lowpan.h

+5 −0
Original line number Diff line number Diff line
@@ -219,6 +219,11 @@ 
#define LOWPAN_NHC_UDP_CHECKSUMC	0x04

#define LOWPAN_NHC_UDP_CHECKSUMI	0x00



#define LOWPAN_NHC_UDP_4BIT_PORT	0xF0B0

#define LOWPAN_NHC_UDP_4BIT_MASK	0xFFF0

#define LOWPAN_NHC_UDP_8BIT_PORT	0xF000

#define LOWPAN_NHC_UDP_8BIT_MASK	0xFF00



/* values for port compression, _with checksum_ ie bit 5 set to 0 */

#define LOWPAN_NHC_UDP_CS_P_00	0xF0 /* all inline */

#define LOWPAN_NHC_UDP_CS_P_01	0xF1 /* source 16bit inline,