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6LoWPAN: UDP header decompression

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

Signed-off-by: Alexander Smirnov <alex.bluesman.smirnov@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
alex.bluesman.smirnov@gmail.com 2011-11-10 07:40:53 +00:00 committed by David S. Miller
parent 3bd5b958c2
commit f8b1b5d231
1 changed files with 60 additions and 1 deletions
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61
net/ieee802154/6lowpan.c
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@ -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);