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Date: Wed, 2 Nov 2011 19:35:11 +0300
From: Alexander Smirnov <alex.bluesman.smirnov@...il.com>
To: davem@...emloft.net
Cc: dbaryshkov@...il.com, linux-zigbee-devel@...ts.sourceforge.net,
netdev@...r.kernel.org,
Alexander Smirnov <alex.bluesman.smirnov@...il.com>
Subject: [PATCH 4/6] [6LoWPAN] UDP header compression
This patch adds support for UDP header compression.
Derived from Contiki OS.
Signed-off-by: Alexander Smirnov <alex.bluesman.smirnov@...il.com>
---
net/ieee802154/6lowpan.c | 51 ++++++++++++++++++++++++++++++++++++++++++---
net/ieee802154/6lowpan.h | 5 ++++
2 files changed, 52 insertions(+), 4 deletions(-)
diff --git a/net/ieee802154/6lowpan.c b/net/ieee802154/6lowpan.c
index c4aae4e..6da3357 100644
--- a/net/ieee802154/6lowpan.c
+++ b/net/ieee802154/6lowpan.c
@@ -365,8 +365,6 @@ 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 +452,53 @@ 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) {
+ 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;
+ }
+
+ /* TODO: other NH types support? */
head[0] = iphc0;
head[1] = iphc1;
diff --git a/net/ieee802154/6lowpan.h b/net/ieee802154/6lowpan.h
index 5d2e5a0..aeff3f3 100644
--- a/net/ieee802154/6lowpan.h
+++ b/net/ieee802154/6lowpan.h
@@ -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,
--
1.7.2.5
--
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