[PATCH bluetooth-next 0/6] 6lowpan: iphc defines and rework tc and flow label handling

[PATCH bluetooth-next 0/6] 6lowpan: iphc defines and rework tc and flow label handling

[Alexander Aring]

Hi,

this patch series based on my previous series "[PATCH bluetooth-next 1/6]
mac802154: llsec: use kzfree" and contains changes for iphc defines and
reworking the tc/flow label handling.

I tested the tc/flow label handling with fakelb and wireshark. So it should
be wrong, when wireshark is wrong also. I hope wireshark has some correct
mechanism to handle it. I used "wireshark 1.12.7".

- Alex

Alexander Aring (6):
  6lowpan: nhc: move iphc manipulation out of nhc
  6lowpan: move IPHC functionality defines
  6lowpan: remove lowpan_is_addr_broadcast
  6lowpan: iphc: change define values
  6lowpan: rework tc and flow label handling
  6lowpan: put mcast compression in an own function

 include/net/6lowpan.h       | 133 -----------
 net/6lowpan/iphc.c          | 565 +++++++++++++++++++++++++++++++-------------
 net/6lowpan/nhc.c           |  13 +-
 net/6lowpan/nhc.h           |   9 +-
 net/6lowpan/nhc_udp.c       |  22 +-
 net/ieee802154/6lowpan/tx.c |   5 +-
 6 files changed, 430 insertions(+), 317 deletions(-)

-- 
2.6.1

[PATCH bluetooth-next 1/6] 6lowpan: nhc: move iphc manipulation out of nhc

[Alexander Aring]

This patch moves the iphc setting of next header commpression bit inside
iphc functionality. Setting of IPHC bits should be happen at iphc.c file
only.

Signed-off-by: Alexander Aring <alex.aring@gmail.com>
---
 net/6lowpan/iphc.c |  9 ++++++---
 net/6lowpan/nhc.c  | 13 +++++--------
 net/6lowpan/nhc.h  |  9 +++------
 3 files changed, 14 insertions(+), 17 deletions(-)

diff --git a/net/6lowpan/iphc.c b/net/6lowpan/iphc.c
index 87d8f1f..afe36aa 100644
--- a/net/6lowpan/iphc.c
+++ b/net/6lowpan/iphc.c
@@ -532,9 +532,12 @@ int lowpan_header_compress(struct sk_buff *skb, const struct net_device *dev,
 	/* Check if we provide the nhc format for nexthdr and compression
 	 * functionality. If not nexthdr is handled inline and not compressed.
 	 */
-	ret = lowpan_nhc_check_compression(skb, hdr, &hc_ptr, &iphc0);
-	if (ret < 0)
-		return ret;
+	ret = lowpan_nhc_check_compression(skb, hdr, &hc_ptr);
+	if (ret == -ENOENT)
+		lowpan_push_hc_data(&hc_ptr, &hdr->nexthdr,
+				    sizeof(hdr->nexthdr));
+	else
+		iphc0 |= LOWPAN_IPHC_NH_C;
 
 	/* Hop limit
 	 * if 1:   compress, encoding is 01
diff --git a/net/6lowpan/nhc.c b/net/6lowpan/nhc.c
index 589224e..7008d53 100644
--- a/net/6lowpan/nhc.c
+++ b/net/6lowpan/nhc.c
@@ -95,23 +95,20 @@ static struct lowpan_nhc *lowpan_nhc_by_nhcid(const struct sk_buff *skb)
 }
 
 int lowpan_nhc_check_compression(struct sk_buff *skb,
-				 const struct ipv6hdr *hdr, u8 **hc_ptr,
-				 u8 *iphc0)
+				 const struct ipv6hdr *hdr, u8 **hc_ptr)
 {
 	struct lowpan_nhc *nhc;
+	int ret = 0;
 
 	spin_lock_bh(&lowpan_nhc_lock);
 
 	nhc = lowpan_nexthdr_nhcs[hdr->nexthdr];
-	if (nhc && nhc->compress)
-		*iphc0 |= LOWPAN_IPHC_NH_C;
-	else
-		lowpan_push_hc_data(hc_ptr, &hdr->nexthdr,
-				    sizeof(hdr->nexthdr));
+	if (!(nhc && nhc->compress))
+		ret = -ENOENT;
 
 	spin_unlock_bh(&lowpan_nhc_lock);
 
-	return 0;
+	return ret;
 }
 
 int lowpan_nhc_do_compression(struct sk_buff *skb, const struct ipv6hdr *hdr,
diff --git a/net/6lowpan/nhc.h b/net/6lowpan/nhc.h
index e3a5644..8030414 100644
--- a/net/6lowpan/nhc.h
+++ b/net/6lowpan/nhc.h
@@ -86,19 +86,16 @@ struct lowpan_nhc *lowpan_nhc_by_nexthdr(u8 nexthdr);
 
 /**
  * lowpan_nhc_check_compression - checks if we support compression format. If
- *	we support the nhc by nexthdr field, the 6LoWPAN iphc NHC bit will be
- *	set. If we don't support nexthdr will be added as inline data to the
- *	6LoWPAN header.
+ *	we support the nhc by nexthdr field, the function will return 0. If we
+ *	don't support the nhc by nexthdr this function will return -ENOENT.
  *
  * @skb: skb of 6LoWPAN header to read nhc and replace header.
  * @hdr: ipv6hdr to check the nexthdr value
  * @hc_ptr: pointer for 6LoWPAN header which should increment at the end of
  *	    replaced header.
- * @iphc0: iphc0 pointer to set the 6LoWPAN NHC bit
  */
 int lowpan_nhc_check_compression(struct sk_buff *skb,
-				 const struct ipv6hdr *hdr, u8 **hc_ptr,
-				 u8 *iphc0);
+				 const struct ipv6hdr *hdr, u8 **hc_ptr);
 
 /**
  * lowpan_nhc_do_compression - calling compress callback for nhc
-- 
2.6.1

[PATCH bluetooth-next 2/6] 6lowpan: move IPHC functionality defines

[Alexander Aring]

This patch removes the IPHC related defines for doing bit manipulation
from global 6lowpan header to the iphc file which should the only one
implementation which use these defines.

Also move next header compression defines to their nhc implementation.

Signed-off-by: Alexander Aring <alex.aring@gmail.com>
---
 include/net/6lowpan.h       | 123 --------------------------------------------
 net/6lowpan/iphc.c          |  88 +++++++++++++++++++++++++++++++
 net/6lowpan/nhc_udp.c       |  22 +++++++-
 net/ieee802154/6lowpan/tx.c |   3 ++
 4 files changed, 112 insertions(+), 124 deletions(-)

diff --git a/include/net/6lowpan.h b/include/net/6lowpan.h
index 4afdbb3..f127a92 100644
--- a/include/net/6lowpan.h
+++ b/include/net/6lowpan.h
@@ -56,11 +56,6 @@
 #include <net/ipv6.h>
 #include <net/net_namespace.h>
 
-#define UIP_802154_SHORTADDR_LEN	2  /* compressed ipv6 address length */
-#define UIP_IPH_LEN			40 /* ipv6 fixed header size */
-#define UIP_PROTO_UDP			17 /* ipv6 next header value for UDP */
-#define UIP_FRAGH_LEN			8  /* ipv6 fragment header size */
-
 #define EUI64_ADDR_LEN		8
 
 #define LOWPAN_NHC_MAX_ID_LEN	1
@@ -79,61 +74,6 @@
 					 LOWPAN_IPHC_MAX_HEADER_LEN +	\
 					 LOWPAN_NHC_MAX_HDR_LEN)
 
-/*
- * ipv6 address based on mac
- * second bit-flip (Universe/Local) is done according RFC2464
- */
-#define is_addr_mac_addr_based(a, m) \
-	((((a)->s6_addr[8])  == (((m)[0]) ^ 0x02)) &&	\
-	 (((a)->s6_addr[9])  == (m)[1]) &&		\
-	 (((a)->s6_addr[10]) == (m)[2]) &&		\
-	 (((a)->s6_addr[11]) == (m)[3]) &&		\
-	 (((a)->s6_addr[12]) == (m)[4]) &&		\
-	 (((a)->s6_addr[13]) == (m)[5]) &&		\
-	 (((a)->s6_addr[14]) == (m)[6]) &&		\
-	 (((a)->s6_addr[15]) == (m)[7]))
-
-/*
- * check whether we can compress the IID to 16 bits,
- * it's possible for unicast adresses with first 49 bits are zero only.
- */
-#define lowpan_is_iid_16_bit_compressable(a)	\
-	((((a)->s6_addr16[4]) == 0) &&		\
-	 (((a)->s6_addr[10]) == 0) &&		\
-	 (((a)->s6_addr[11]) == 0xff) &&	\
-	 (((a)->s6_addr[12]) == 0xfe) &&	\
-	 (((a)->s6_addr[13]) == 0))
-
-/* check whether the 112-bit gid of the multicast address is mappable to: */
-
-/* 48 bits, FFXX::00XX:XXXX:XXXX */
-#define lowpan_is_mcast_addr_compressable48(a)	\
-	((((a)->s6_addr16[1]) == 0) &&		\
-	 (((a)->s6_addr16[2]) == 0) &&		\
-	 (((a)->s6_addr16[3]) == 0) &&		\
-	 (((a)->s6_addr16[4]) == 0) &&		\
-	 (((a)->s6_addr[10]) == 0))
-
-/* 32 bits, FFXX::00XX:XXXX */
-#define lowpan_is_mcast_addr_compressable32(a)	\
-	((((a)->s6_addr16[1]) == 0) &&		\
-	 (((a)->s6_addr16[2]) == 0) &&		\
-	 (((a)->s6_addr16[3]) == 0) &&		\
-	 (((a)->s6_addr16[4]) == 0) &&		\
-	 (((a)->s6_addr16[5]) == 0) &&		\
-	 (((a)->s6_addr[12]) == 0))
-
-/* 8 bits, FF02::00XX */
-#define lowpan_is_mcast_addr_compressable8(a)	\
-	((((a)->s6_addr[1])  == 2) &&		\
-	 (((a)->s6_addr16[1]) == 0) &&		\
-	 (((a)->s6_addr16[2]) == 0) &&		\
-	 (((a)->s6_addr16[3]) == 0) &&		\
-	 (((a)->s6_addr16[4]) == 0) &&		\
-	 (((a)->s6_addr16[5]) == 0) &&		\
-	 (((a)->s6_addr16[6]) == 0) &&		\
-	 (((a)->s6_addr[14]) == 0))
-
 #define lowpan_is_addr_broadcast(a)	\
 	((((a)[0]) == 0xFF) &&	\
 	 (((a)[1]) == 0xFF) &&	\
@@ -158,69 +98,6 @@ static inline bool lowpan_is_iphc(u8 dispatch)
 	return (dispatch & LOWPAN_DISPATCH_IPHC_MASK) == LOWPAN_DISPATCH_IPHC;
 }
 
-#define LOWPAN_FRAG_TIMEOUT	(HZ * 60)	/* time-out 60 sec */
-
-#define LOWPAN_FRAG1_HEAD_SIZE	0x4
-#define LOWPAN_FRAGN_HEAD_SIZE	0x5
-
-/*
- * Values of fields within the IPHC encoding first byte
- * (C stands for compressed and I for inline)
- */
-#define LOWPAN_IPHC_TF		0x18
-
-#define LOWPAN_IPHC_FL_C	0x10
-#define LOWPAN_IPHC_TC_C	0x08
-#define LOWPAN_IPHC_NH_C	0x04
-#define LOWPAN_IPHC_TTL_1	0x01
-#define LOWPAN_IPHC_TTL_64	0x02
-#define LOWPAN_IPHC_TTL_255	0x03
-#define LOWPAN_IPHC_TTL_I	0x00
-
-
-/* Values of fields within the IPHC encoding second byte */
-#define LOWPAN_IPHC_CID		0x80
-
-#define LOWPAN_IPHC_ADDR_00	0x00
-#define LOWPAN_IPHC_ADDR_01	0x01
-#define LOWPAN_IPHC_ADDR_02	0x02
-#define LOWPAN_IPHC_ADDR_03	0x03
-
-#define LOWPAN_IPHC_SAC		0x40
-#define LOWPAN_IPHC_SAM		0x30
-
-#define LOWPAN_IPHC_SAM_BIT	4
-
-#define LOWPAN_IPHC_M		0x08
-#define LOWPAN_IPHC_DAC		0x04
-#define LOWPAN_IPHC_DAM_00	0x00
-#define LOWPAN_IPHC_DAM_01	0x01
-#define LOWPAN_IPHC_DAM_10	0x02
-#define LOWPAN_IPHC_DAM_11	0x03
-
-#define LOWPAN_IPHC_DAM_BIT	0
-/*
- * LOWPAN_UDP encoding (works together with IPHC)
- */
-#define LOWPAN_NHC_UDP_MASK		0xF8
-#define LOWPAN_NHC_UDP_ID		0xF0
-#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,
-					dest = 0xF0 + 8 bit inline */
-#define LOWPAN_NHC_UDP_CS_P_10	0xF2 /* source = 0xF0 + 8bit inline,
-					dest = 16 bit inline */
-#define LOWPAN_NHC_UDP_CS_P_11	0xF3 /* source & dest = 0xF0B + 4bit inline */
-#define LOWPAN_NHC_UDP_CS_C	0x04 /* checksum elided */
-
 #define LOWPAN_PRIV_SIZE(llpriv_size)	\
 	(sizeof(struct lowpan_priv) + llpriv_size)
 
diff --git a/net/6lowpan/iphc.c b/net/6lowpan/iphc.c
index afe36aa..fcf583f 100644
--- a/net/6lowpan/iphc.c
+++ b/net/6lowpan/iphc.c
@@ -58,6 +58,94 @@
 
 #include "nhc.h"
 
+/* Values of fields within the IPHC encoding first byte
+ * (C stands for compressed and I for inline)
+ */
+#define LOWPAN_IPHC_TF		0x18
+
+#define LOWPAN_IPHC_FL_C	0x10
+#define LOWPAN_IPHC_TC_C	0x08
+#define LOWPAN_IPHC_NH_C	0x04
+#define LOWPAN_IPHC_TTL_1	0x01
+#define LOWPAN_IPHC_TTL_64	0x02
+#define LOWPAN_IPHC_TTL_255	0x03
+#define LOWPAN_IPHC_TTL_I	0x00
+
+/* Values of fields within the IPHC encoding second byte */
+#define LOWPAN_IPHC_CID		0x80
+
+#define LOWPAN_IPHC_ADDR_00	0x00
+#define LOWPAN_IPHC_ADDR_01	0x01
+#define LOWPAN_IPHC_ADDR_02	0x02
+#define LOWPAN_IPHC_ADDR_03	0x03
+
+#define LOWPAN_IPHC_SAC		0x40
+#define LOWPAN_IPHC_SAM		0x30
+
+#define LOWPAN_IPHC_SAM_BIT	4
+
+#define LOWPAN_IPHC_M		0x08
+#define LOWPAN_IPHC_DAC		0x04
+#define LOWPAN_IPHC_DAM_00	0x00
+#define LOWPAN_IPHC_DAM_01	0x01
+#define LOWPAN_IPHC_DAM_10	0x02
+#define LOWPAN_IPHC_DAM_11	0x03
+
+#define LOWPAN_IPHC_DAM_BIT	0
+
+/* ipv6 address based on mac
+ * second bit-flip (Universe/Local) is done according RFC2464
+ */
+#define is_addr_mac_addr_based(a, m) \
+	((((a)->s6_addr[8])  == (((m)[0]) ^ 0x02)) &&	\
+	 (((a)->s6_addr[9])  == (m)[1]) &&		\
+	 (((a)->s6_addr[10]) == (m)[2]) &&		\
+	 (((a)->s6_addr[11]) == (m)[3]) &&		\
+	 (((a)->s6_addr[12]) == (m)[4]) &&		\
+	 (((a)->s6_addr[13]) == (m)[5]) &&		\
+	 (((a)->s6_addr[14]) == (m)[6]) &&		\
+	 (((a)->s6_addr[15]) == (m)[7]))
+
+/* check whether we can compress the IID to 16 bits,
+ * it's possible for unicast addresses with first 49 bits are zero only.
+ */
+#define lowpan_is_iid_16_bit_compressable(a)	\
+	((((a)->s6_addr16[4]) == 0) &&		\
+	 (((a)->s6_addr[10]) == 0) &&		\
+	 (((a)->s6_addr[11]) == 0xff) &&	\
+	 (((a)->s6_addr[12]) == 0xfe) &&	\
+	 (((a)->s6_addr[13]) == 0))
+
+/* check whether the 112-bit gid of the multicast address is mappable to: */
+
+/* 48 bits, FFXX::00XX:XXXX:XXXX */
+#define lowpan_is_mcast_addr_compressable48(a)	\
+	((((a)->s6_addr16[1]) == 0) &&		\
+	 (((a)->s6_addr16[2]) == 0) &&		\
+	 (((a)->s6_addr16[3]) == 0) &&		\
+	 (((a)->s6_addr16[4]) == 0) &&		\
+	 (((a)->s6_addr[10]) == 0))
+
+/* 32 bits, FFXX::00XX:XXXX */
+#define lowpan_is_mcast_addr_compressable32(a)	\
+	((((a)->s6_addr16[1]) == 0) &&		\
+	 (((a)->s6_addr16[2]) == 0) &&		\
+	 (((a)->s6_addr16[3]) == 0) &&		\
+	 (((a)->s6_addr16[4]) == 0) &&		\
+	 (((a)->s6_addr16[5]) == 0) &&		\
+	 (((a)->s6_addr[12]) == 0))
+
+/* 8 bits, FF02::00XX */
+#define lowpan_is_mcast_addr_compressable8(a)	\
+	((((a)->s6_addr[1])  == 2) &&		\
+	 (((a)->s6_addr16[1]) == 0) &&		\
+	 (((a)->s6_addr16[2]) == 0) &&		\
+	 (((a)->s6_addr16[3]) == 0) &&		\
+	 (((a)->s6_addr16[4]) == 0) &&		\
+	 (((a)->s6_addr16[5]) == 0) &&		\
+	 (((a)->s6_addr16[6]) == 0) &&		\
+	 (((a)->s6_addr[14]) == 0))
+
 static inline void iphc_uncompress_eui64_lladdr(struct in6_addr *ipaddr,
 						const void *lladdr)
 {
diff --git a/net/6lowpan/nhc_udp.c b/net/6lowpan/nhc_udp.c
index 72d0b57..69537a2 100644
--- a/net/6lowpan/nhc_udp.c
+++ b/net/6lowpan/nhc_udp.c
@@ -17,7 +17,27 @@
 
 #include "nhc.h"
 
-#define LOWPAN_NHC_UDP_IDLEN	1
+#define LOWPAN_NHC_UDP_MASK		0xF8
+#define LOWPAN_NHC_UDP_ID		0xF0
+#define LOWPAN_NHC_UDP_IDLEN		1
+
+#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 */
+
+/* all inline */
+#define LOWPAN_NHC_UDP_CS_P_00	0xF0
+/* source 16bit inline, dest = 0xF0 + 8 bit inline */
+#define LOWPAN_NHC_UDP_CS_P_01	0xF1
+/* source = 0xF0 + 8bit inline, dest = 16 bit inline */
+#define LOWPAN_NHC_UDP_CS_P_10	0xF2
+/* source & dest = 0xF0B + 4bit inline */
+#define LOWPAN_NHC_UDP_CS_P_11	0xF3
+/* checksum elided */
+#define LOWPAN_NHC_UDP_CS_C	0x04
 
 static int udp_uncompress(struct sk_buff *skb, size_t needed)
 {
diff --git a/net/ieee802154/6lowpan/tx.c b/net/ieee802154/6lowpan/tx.c
index 2a5b2c2..f6594a8 100644
--- a/net/ieee802154/6lowpan/tx.c
+++ b/net/ieee802154/6lowpan/tx.c
@@ -14,6 +14,9 @@
 
 #include "6lowpan_i.h"
 
+#define LOWPAN_FRAG1_HEAD_SIZE	0x4
+#define LOWPAN_FRAGN_HEAD_SIZE	0x5
+
 /* don't save pan id, it's intra pan */
 struct lowpan_addr {
 	u8 mode;
-- 
2.6.1

[PATCH bluetooth-next 3/6] 6lowpan: remove lowpan_is_addr_broadcast

[Alexander Aring]

This macro is used at 802.15.4 6LoWPAN only and can be replaced by
memcmp with the interface broadcast address.

Signed-off-by: Alexander Aring <alex.aring@gmail.com>
---
 include/net/6lowpan.h       | 10 ----------
 net/ieee802154/6lowpan/tx.c |  2 +-
 2 files changed, 1 insertion(+), 11 deletions(-)

diff --git a/include/net/6lowpan.h b/include/net/6lowpan.h
index f127a92..cf3bc56 100644
--- a/include/net/6lowpan.h
+++ b/include/net/6lowpan.h
@@ -74,16 +74,6 @@
 					 LOWPAN_IPHC_MAX_HEADER_LEN +	\
 					 LOWPAN_NHC_MAX_HDR_LEN)
 
-#define lowpan_is_addr_broadcast(a)	\
-	((((a)[0]) == 0xFF) &&	\
-	 (((a)[1]) == 0xFF) &&	\
-	 (((a)[2]) == 0xFF) &&	\
-	 (((a)[3]) == 0xFF) &&	\
-	 (((a)[4]) == 0xFF) &&	\
-	 (((a)[5]) == 0xFF) &&	\
-	 (((a)[6]) == 0xFF) &&	\
-	 (((a)[7]) == 0xFF))
-
 #define LOWPAN_DISPATCH_IPV6		0x41 /* 01000001 = 65 */
 #define LOWPAN_DISPATCH_IPHC		0x60 /* 011xxxxx = ... */
 #define LOWPAN_DISPATCH_IPHC_MASK	0xe0
diff --git a/net/ieee802154/6lowpan/tx.c b/net/ieee802154/6lowpan/tx.c
index f6594a8..d4353fa 100644
--- a/net/ieee802154/6lowpan/tx.c
+++ b/net/ieee802154/6lowpan/tx.c
@@ -238,7 +238,7 @@ static int lowpan_header(struct sk_buff *skb, struct net_device *ldev,
 	/* if the destination address is the broadcast address, use the
 	 * corresponding short address
 	 */
-	if (lowpan_is_addr_broadcast((const u8 *)daddr)) {
+	if (!memcmp(daddr, ldev->broadcast, EUI64_ADDR_LEN)) {
 		da.mode = IEEE802154_ADDR_SHORT;
 		da.short_addr = cpu_to_le16(IEEE802154_ADDR_BROADCAST);
 		cb->ackreq = false;
-- 
2.6.1

[PATCH bluetooth-next 4/6] 6lowpan: iphc: change define values

[Alexander Aring]

This patch has the main goal to delete shift operations. Instead we
doing masks and equals afterwards. E.g. for the SAM evaluation we
masking only the SAM value which fits in iphc1 byte, then comparing with
all possible SAM values over a switch case statement. We will not
shifting the SAM value to somewhat readable anymore.
Additional this patch slighty change the naming style like RFC 6282,
e.g. TTL to HLIM and we will drop an errno now if CID flag is set,
because we don't support it.

Signed-off-by: Alexander Aring <alex.aring@gmail.com>
---
 net/6lowpan/iphc.c | 199 ++++++++++++++++++++++++++++-------------------------
 1 file changed, 106 insertions(+), 93 deletions(-)

diff --git a/net/6lowpan/iphc.c b/net/6lowpan/iphc.c
index fcf583f..af8af98 100644
--- a/net/6lowpan/iphc.c
+++ b/net/6lowpan/iphc.c
@@ -58,41 +58,42 @@
 
 #include "nhc.h"
 
-/* Values of fields within the IPHC encoding first byte
- * (C stands for compressed and I for inline)
- */
-#define LOWPAN_IPHC_TF		0x18
+/* Values of fields within the IPHC encoding first byte */
+#define LOWPAN_IPHC_TF_MASK	0x18
+#define LOWPAN_IPHC_TF_00	0x00
+#define LOWPAN_IPHC_TF_01	0x08
+#define LOWPAN_IPHC_TF_10	0x10
+#define LOWPAN_IPHC_TF_11	0x18
+
+#define LOWPAN_IPHC_NH		0x04
 
-#define LOWPAN_IPHC_FL_C	0x10
-#define LOWPAN_IPHC_TC_C	0x08
-#define LOWPAN_IPHC_NH_C	0x04
-#define LOWPAN_IPHC_TTL_1	0x01
-#define LOWPAN_IPHC_TTL_64	0x02
-#define LOWPAN_IPHC_TTL_255	0x03
-#define LOWPAN_IPHC_TTL_I	0x00
+#define LOWPAN_IPHC_HLIM_MASK	0x03
+#define LOWPAN_IPHC_HLIM_00	0x00
+#define LOWPAN_IPHC_HLIM_01	0x01
+#define LOWPAN_IPHC_HLIM_10	0x02
+#define LOWPAN_IPHC_HLIM_11	0x03
 
 /* Values of fields within the IPHC encoding second byte */
 #define LOWPAN_IPHC_CID		0x80
 
-#define LOWPAN_IPHC_ADDR_00	0x00
-#define LOWPAN_IPHC_ADDR_01	0x01
-#define LOWPAN_IPHC_ADDR_02	0x02
-#define LOWPAN_IPHC_ADDR_03	0x03
-
 #define LOWPAN_IPHC_SAC		0x40
-#define LOWPAN_IPHC_SAM		0x30
 
-#define LOWPAN_IPHC_SAM_BIT	4
+#define LOWPAN_IPHC_SAM_MASK	0x30
+#define LOWPAN_IPHC_SAM_00	0x00
+#define LOWPAN_IPHC_SAM_01	0x10
+#define LOWPAN_IPHC_SAM_10	0x20
+#define LOWPAN_IPHC_SAM_11	0x30
 
 #define LOWPAN_IPHC_M		0x08
+
 #define LOWPAN_IPHC_DAC		0x04
+
+#define LOWPAN_IPHC_DAM_MASK	0x03
 #define LOWPAN_IPHC_DAM_00	0x00
 #define LOWPAN_IPHC_DAM_01	0x01
 #define LOWPAN_IPHC_DAM_10	0x02
 #define LOWPAN_IPHC_DAM_11	0x03
 
-#define LOWPAN_IPHC_DAM_BIT	0
-
 /* ipv6 address based on mac
  * second bit-flip (Universe/Local) is done according RFC2464
  */
@@ -197,7 +198,7 @@ static inline void iphc_uncompress_802154_lladdr(struct in6_addr *ipaddr,
 /* Uncompress address function for source and
  * destination address(non-multicast).
  *
- * address_mode is sam value or dam value.
+ * address_mode is the masked value for sam or dam value
  */
 static int uncompress_addr(struct sk_buff *skb, const struct net_device *dev,
 			   struct in6_addr *ipaddr, u8 address_mode,
@@ -206,17 +207,20 @@ static int uncompress_addr(struct sk_buff *skb, const struct net_device *dev,
 	bool fail;
 
 	switch (address_mode) {
-	case LOWPAN_IPHC_ADDR_00:
+	/* SAM and DAM are the same here */
+	case LOWPAN_IPHC_DAM_00:
 		/* for global link addresses */
 		fail = lowpan_fetch_skb(skb, ipaddr->s6_addr, 16);
 		break;
-	case LOWPAN_IPHC_ADDR_01:
+	case LOWPAN_IPHC_SAM_01:
+	case LOWPAN_IPHC_DAM_01:
 		/* fe:80::XXXX:XXXX:XXXX:XXXX */
 		ipaddr->s6_addr[0] = 0xFE;
 		ipaddr->s6_addr[1] = 0x80;
 		fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[8], 8);
 		break;
-	case LOWPAN_IPHC_ADDR_02:
+	case LOWPAN_IPHC_SAM_10:
+	case LOWPAN_IPHC_DAM_10:
 		/* fe:80::ff:fe00:XXXX */
 		ipaddr->s6_addr[0] = 0xFE;
 		ipaddr->s6_addr[1] = 0x80;
@@ -224,7 +228,8 @@ static int uncompress_addr(struct sk_buff *skb, const struct net_device *dev,
 		ipaddr->s6_addr[12] = 0xFE;
 		fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[14], 2);
 		break;
-	case LOWPAN_IPHC_ADDR_03:
+	case LOWPAN_IPHC_SAM_11:
+	case LOWPAN_IPHC_DAM_11:
 		fail = false;
 		switch (lowpan_priv(dev)->lltype) {
 		case LOWPAN_LLTYPE_IEEE802154:
@@ -256,24 +261,25 @@ static int uncompress_addr(struct sk_buff *skb, const struct net_device *dev,
  */
 static int uncompress_context_based_src_addr(struct sk_buff *skb,
 					     struct in6_addr *ipaddr,
-					     const u8 sam)
+					     u8 address_mode)
 {
-	switch (sam) {
-	case LOWPAN_IPHC_ADDR_00:
+	switch (address_mode) {
+	case LOWPAN_IPHC_SAM_00:
 		/* unspec address ::
 		 * Do nothing, address is already ::
 		 */
 		break;
-	case LOWPAN_IPHC_ADDR_01:
+	case LOWPAN_IPHC_SAM_01:
 		/* TODO */
-	case LOWPAN_IPHC_ADDR_02:
+	case LOWPAN_IPHC_SAM_10:
 		/* TODO */
-	case LOWPAN_IPHC_ADDR_03:
+	case LOWPAN_IPHC_SAM_11:
 		/* TODO */
-		netdev_warn(skb->dev, "SAM value 0x%x not supported\n", sam);
+		netdev_warn(skb->dev, "SAM value 0x%x not supported\n",
+			    address_mode);
 		return -EINVAL;
 	default:
-		pr_debug("Invalid sam value: 0x%x\n", sam);
+		pr_debug("Invalid sam value: 0x%x\n", address_mode);
 		return -EINVAL;
 	}
 
@@ -289,11 +295,11 @@ static int uncompress_context_based_src_addr(struct sk_buff *skb,
  */
 static int lowpan_uncompress_multicast_daddr(struct sk_buff *skb,
 					     struct in6_addr *ipaddr,
-					     const u8 dam)
+					     u8 address_mode)
 {
 	bool fail;
 
-	switch (dam) {
+	switch (address_mode) {
 	case LOWPAN_IPHC_DAM_00:
 		/* 00:  128 bits.  The full address
 		 * is carried in-line.
@@ -325,7 +331,7 @@ static int lowpan_uncompress_multicast_daddr(struct sk_buff *skb,
 		fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[15], 1);
 		break;
 	default:
-		pr_debug("DAM value has a wrong value: 0x%x\n", dam);
+		pr_debug("DAM value has a wrong value: 0x%x\n", address_mode);
 		return -EINVAL;
 	}
 
@@ -341,13 +347,17 @@ static int lowpan_uncompress_multicast_daddr(struct sk_buff *skb,
 }
 
 /* TTL uncompression values */
-static const u8 lowpan_ttl_values[] = { 0, 1, 64, 255 };
+static const u8 lowpan_ttl_values[] = {
+	[LOWPAN_IPHC_HLIM_01] = 1,
+	[LOWPAN_IPHC_HLIM_10] = 64,
+	[LOWPAN_IPHC_HLIM_11] = 255,
+};
 
 int lowpan_header_decompress(struct sk_buff *skb, const struct net_device *dev,
 			     const void *daddr, const void *saddr)
 {
 	struct ipv6hdr hdr = {};
-	u8 iphc0, iphc1, tmp, num_context = 0;
+	u8 iphc0, iphc1, tmp = 0;
 	int err;
 
 	raw_dump_table(__func__, "raw skb data dump uncompressed",
@@ -358,20 +368,17 @@ int lowpan_header_decompress(struct sk_buff *skb, const struct net_device *dev,
 		return -EINVAL;
 
 	/* another if the CID flag is set */
-	if (iphc1 & LOWPAN_IPHC_CID) {
-		pr_debug("CID flag is set, increase header with one\n");
-		if (lowpan_fetch_skb(skb, &num_context, sizeof(num_context)))
-			return -EINVAL;
-	}
+	if (iphc1 & LOWPAN_IPHC_CID)
+		return -ENOTSUPP;
 
 	hdr.version = 6;
 
 	/* Traffic Class and Flow Label */
-	switch ((iphc0 & LOWPAN_IPHC_TF) >> 3) {
+	switch (iphc0 & LOWPAN_IPHC_TF_MASK) {
 	/* Traffic Class and FLow Label carried in-line
 	 * ECN + DSCP + 4-bit Pad + Flow Label (4 bytes)
 	 */
-	case 0: /* 00b */
+	case LOWPAN_IPHC_TF_00:
 		if (lowpan_fetch_skb(skb, &tmp, sizeof(tmp)))
 			return -EINVAL;
 
@@ -381,20 +388,10 @@ int lowpan_header_decompress(struct sk_buff *skb, const struct net_device *dev,
 		hdr.flow_lbl[0] = ((tmp >> 2) & 0x30) | (tmp << 6) |
 					(hdr.flow_lbl[0] & 0x0f);
 		break;
-	/* Traffic class carried in-line
-	 * ECN + DSCP (1 byte), Flow Label is elided
-	 */
-	case 2: /* 10b */
-		if (lowpan_fetch_skb(skb, &tmp, sizeof(tmp)))
-			return -EINVAL;
-
-		hdr.priority = ((tmp >> 2) & 0x0f);
-		hdr.flow_lbl[0] = ((tmp << 6) & 0xC0) | ((tmp >> 2) & 0x30);
-		break;
 	/* Flow Label carried in-line
 	 * ECN + 2-bit Pad + Flow Label (3 bytes), DSCP is elided
 	 */
-	case 1: /* 01b */
+	case LOWPAN_IPHC_TF_01:
 		if (lowpan_fetch_skb(skb, &tmp, sizeof(tmp)))
 			return -EINVAL;
 
@@ -402,15 +399,26 @@ int lowpan_header_decompress(struct sk_buff *skb, const struct net_device *dev,
 		memcpy(&hdr.flow_lbl[1], &skb->data[0], 2);
 		skb_pull(skb, 2);
 		break;
+	/* Traffic class carried in-line
+	 * ECN + DSCP (1 byte), Flow Label is elided
+	 */
+	case LOWPAN_IPHC_TF_10:
+		if (lowpan_fetch_skb(skb, &tmp, sizeof(tmp)))
+			return -EINVAL;
+
+		hdr.priority = ((tmp >> 2) & 0x0f);
+		hdr.flow_lbl[0] = ((tmp << 6) & 0xC0) | ((tmp >> 2) & 0x30);
+		break;
 	/* Traffic Class and Flow Label are elided */
-	case 3: /* 11b */
+	case LOWPAN_IPHC_TF_11:
 		break;
 	default:
+		WARN_ON_ONCE(1);
 		break;
 	}
 
 	/* Next Header */
-	if ((iphc0 & LOWPAN_IPHC_NH_C) == 0) {
+	if (!(iphc0 & LOWPAN_IPHC_NH)) {
 		/* Next header is carried inline */
 		if (lowpan_fetch_skb(skb, &hdr.nexthdr, sizeof(hdr.nexthdr)))
 			return -EINVAL;
@@ -420,34 +428,30 @@ int lowpan_header_decompress(struct sk_buff *skb, const struct net_device *dev,
 	}
 
 	/* Hop Limit */
-	if ((iphc0 & 0x03) != LOWPAN_IPHC_TTL_I) {
-		hdr.hop_limit = lowpan_ttl_values[iphc0 & 0x03];
+	if ((iphc0 & LOWPAN_IPHC_HLIM_MASK) != LOWPAN_IPHC_HLIM_00) {
+		hdr.hop_limit = lowpan_ttl_values[iphc0 & LOWPAN_IPHC_HLIM_MASK];
 	} else {
 		if (lowpan_fetch_skb(skb, &hdr.hop_limit,
 				     sizeof(hdr.hop_limit)))
 			return -EINVAL;
 	}
 
-	/* Extract SAM to the tmp variable */
-	tmp = ((iphc1 & LOWPAN_IPHC_SAM) >> LOWPAN_IPHC_SAM_BIT) & 0x03;
-
 	if (iphc1 & LOWPAN_IPHC_SAC) {
 		/* Source address context based uncompression */
 		pr_debug("SAC bit is set. Handle context based source address.\n");
-		err = uncompress_context_based_src_addr(skb, &hdr.saddr, tmp);
+		err = uncompress_context_based_src_addr(skb, &hdr.saddr,
+							iphc1 & LOWPAN_IPHC_SAM_MASK);
 	} else {
 		/* Source address uncompression */
 		pr_debug("source address stateless compression\n");
-		err = uncompress_addr(skb, dev, &hdr.saddr, tmp, saddr);
+		err = uncompress_addr(skb, dev, &hdr.saddr,
+				      iphc1 & LOWPAN_IPHC_SAM_MASK, saddr);
 	}
 
 	/* Check on error of previous branch */
 	if (err)
 		return -EINVAL;
 
-	/* Extract DAM to the tmp variable */
-	tmp = ((iphc1 & LOWPAN_IPHC_DAM_11) >> LOWPAN_IPHC_DAM_BIT) & 0x03;
-
 	/* check for Multicast Compression */
 	if (iphc1 & LOWPAN_IPHC_M) {
 		if (iphc1 & LOWPAN_IPHC_DAC) {
@@ -455,21 +459,22 @@ int lowpan_header_decompress(struct sk_buff *skb, const struct net_device *dev,
 			/* TODO: implement this */
 		} else {
 			err = lowpan_uncompress_multicast_daddr(skb, &hdr.daddr,
-								tmp);
+								iphc1 & LOWPAN_IPHC_DAM_MASK);
 
 			if (err)
 				return -EINVAL;
 		}
 	} else {
-		err = uncompress_addr(skb, dev, &hdr.daddr, tmp, daddr);
+		err = uncompress_addr(skb, dev, &hdr.daddr,
+				      iphc1 & LOWPAN_IPHC_DAM_MASK, daddr);
 		pr_debug("dest: stateless compression mode %d dest %pI6c\n",
-			 tmp, &hdr.daddr);
+			 iphc1 & LOWPAN_IPHC_DAM_MASK, &hdr.daddr);
 		if (err)
 			return -EINVAL;
 	}
 
 	/* Next header data uncompression */
-	if (iphc0 & LOWPAN_IPHC_NH_C) {
+	if (iphc0 & LOWPAN_IPHC_NH) {
 		err = lowpan_nhc_do_uncompression(skb, dev, &hdr);
 		if (err < 0)
 			return err;
@@ -510,30 +515,39 @@ int lowpan_header_decompress(struct sk_buff *skb, const struct net_device *dev,
 }
 EXPORT_SYMBOL_GPL(lowpan_header_decompress);
 
-static u8 lowpan_compress_addr_64(u8 **hc_ptr, u8 shift,
-				  const struct in6_addr *ipaddr,
-				  const unsigned char *lladdr)
+static const u8 lowpan_iphc_dam_to_sam_value[] = {
+	[LOWPAN_IPHC_DAM_00] = LOWPAN_IPHC_SAM_00,
+	[LOWPAN_IPHC_DAM_01] = LOWPAN_IPHC_SAM_01,
+	[LOWPAN_IPHC_DAM_10] = LOWPAN_IPHC_SAM_10,
+	[LOWPAN_IPHC_DAM_11] = LOWPAN_IPHC_SAM_11,
+};
+
+static u8 lowpan_compress_addr_64(u8 **hc_ptr, const struct in6_addr *ipaddr,
+				  const unsigned char *lladdr, bool sam)
 {
-	u8 val = 0;
+	u8 dam = LOWPAN_IPHC_DAM_00;
 
 	if (is_addr_mac_addr_based(ipaddr, lladdr)) {
-		val = 3; /* 0-bits */
+		dam = LOWPAN_IPHC_DAM_11; /* 0-bits */
 		pr_debug("address compression 0 bits\n");
 	} else if (lowpan_is_iid_16_bit_compressable(ipaddr)) {
 		/* compress IID to 16 bits xxxx::XXXX */
 		lowpan_push_hc_data(hc_ptr, &ipaddr->s6_addr16[7], 2);
-		val = 2; /* 16-bits */
+		dam = LOWPAN_IPHC_DAM_10; /* 16-bits */
 		raw_dump_inline(NULL, "Compressed ipv6 addr is (16 bits)",
 				*hc_ptr - 2, 2);
 	} else {
 		/* do not compress IID => xxxx::IID */
 		lowpan_push_hc_data(hc_ptr, &ipaddr->s6_addr16[4], 8);
-		val = 1; /* 64-bits */
+		dam = LOWPAN_IPHC_DAM_01; /* 64-bits */
 		raw_dump_inline(NULL, "Compressed ipv6 addr is (64 bits)",
 				*hc_ptr - 8, 8);
 	}
 
-	return rol8(val, shift);
+	if (sam)
+		return lowpan_iphc_dam_to_sam_value[dam];
+	else
+		return dam;
 }
 
 int lowpan_header_compress(struct sk_buff *skb, const struct net_device *dev,
@@ -587,11 +601,11 @@ int lowpan_header_compress(struct sk_buff *skb, const struct net_device *dev,
 	if (((hdr->flow_lbl[0] & 0x0F) == 0) &&
 	    (hdr->flow_lbl[1] == 0) && (hdr->flow_lbl[2] == 0)) {
 		/* flow label can be compressed */
-		iphc0 |= LOWPAN_IPHC_FL_C;
+		iphc0 |= LOWPAN_IPHC_TF_10;
 		if ((hdr->priority == 0) &&
 		    ((hdr->flow_lbl[0] & 0xF0) == 0)) {
 			/* compress (elide) all */
-			iphc0 |= LOWPAN_IPHC_TC_C;
+			iphc0 |= LOWPAN_IPHC_TF_11;
 		} else {
 			/* compress only the flow label */
 			*hc_ptr = tmp;
@@ -602,7 +616,7 @@ int lowpan_header_compress(struct sk_buff *skb, const struct net_device *dev,
 		if ((hdr->priority == 0) &&
 		    ((hdr->flow_lbl[0] & 0xF0) == 0)) {
 			/* compress only traffic class */
-			iphc0 |= LOWPAN_IPHC_TC_C;
+			iphc0 |= LOWPAN_IPHC_TF_01;
 			*hc_ptr = (tmp & 0xc0) | (hdr->flow_lbl[0] & 0x0F);
 			memcpy(hc_ptr + 1, &hdr->flow_lbl[1], 2);
 			hc_ptr += 3;
@@ -625,7 +639,7 @@ int lowpan_header_compress(struct sk_buff *skb, const struct net_device *dev,
 		lowpan_push_hc_data(&hc_ptr, &hdr->nexthdr,
 				    sizeof(hdr->nexthdr));
 	else
-		iphc0 |= LOWPAN_IPHC_NH_C;
+		iphc0 |= LOWPAN_IPHC_NH;
 
 	/* Hop limit
 	 * if 1:   compress, encoding is 01
@@ -635,13 +649,13 @@ int lowpan_header_compress(struct sk_buff *skb, const struct net_device *dev,
 	 */
 	switch (hdr->hop_limit) {
 	case 1:
-		iphc0 |= LOWPAN_IPHC_TTL_1;
+		iphc0 |= LOWPAN_IPHC_HLIM_01;
 		break;
 	case 64:
-		iphc0 |= LOWPAN_IPHC_TTL_64;
+		iphc0 |= LOWPAN_IPHC_HLIM_10;
 		break;
 	case 255:
-		iphc0 |= LOWPAN_IPHC_TTL_255;
+		iphc0 |= LOWPAN_IPHC_HLIM_11;
 		break;
 	default:
 		lowpan_push_hc_data(&hc_ptr, &hdr->hop_limit,
@@ -655,9 +669,8 @@ int lowpan_header_compress(struct sk_buff *skb, const struct net_device *dev,
 		iphc1 |= LOWPAN_IPHC_SAC;
 	} else {
 		if (addr_type & IPV6_ADDR_LINKLOCAL) {
-			iphc1 |= lowpan_compress_addr_64(&hc_ptr,
-							 LOWPAN_IPHC_SAM_BIT,
-							 &hdr->saddr, saddr);
+			iphc1 |= lowpan_compress_addr_64(&hc_ptr, &hdr->saddr,
+							 saddr, true);
 			pr_debug("source address unicast link-local %pI6c iphc1 0x%02x\n",
 				 &hdr->saddr, iphc1);
 		} else {
@@ -701,8 +714,8 @@ int lowpan_header_compress(struct sk_buff *skb, const struct net_device *dev,
 	} else {
 		if (addr_type & IPV6_ADDR_LINKLOCAL) {
 			/* TODO: context lookup */
-			iphc1 |= lowpan_compress_addr_64(&hc_ptr,
-				LOWPAN_IPHC_DAM_BIT, &hdr->daddr, daddr);
+			iphc1 |= lowpan_compress_addr_64(&hc_ptr, &hdr->daddr,
+							 daddr, false);
 			pr_debug("dest address unicast link-local %pI6c "
 				 "iphc1 0x%02x\n", &hdr->daddr, iphc1);
 		} else {
@@ -712,7 +725,7 @@ int lowpan_header_compress(struct sk_buff *skb, const struct net_device *dev,
 	}
 
 	/* next header compression */
-	if (iphc0 & LOWPAN_IPHC_NH_C) {
+	if (iphc0 & LOWPAN_IPHC_NH) {
 		ret = lowpan_nhc_do_compression(skb, hdr, &hc_ptr);
 		if (ret < 0)
 			return ret;
-- 
2.6.1

[PATCH bluetooth-next 5/6] 6lowpan: rework tc and flow label handling

[Alexander Aring]

This patch reworks the handling of compression/decompression of traffic
class and flow label handling. The current method is hard to understand,
also doesn't checks if we can read the buffer from skb length.

I tried to put the shifting operations into static inline functions and
comment each steps which I did there to make it hopefully somewhat more
readable. The big mess to deal with that is the that the ipv6 header
bring the order "DSCP + ECN" but iphc uses "ECN + DSCP". Additional the
DCSP + ECN bits are splitted in ipv6_hdr inside the priority and
flow_lbl[0] fields.

I tested these compressions by using fakelb 802.15.4 driver and
manipulate the tc and flow label fields manually in function
"__ip6_local_out" before the skb will be send to lower layers. Then I
looked up the tc and flow label fields in wireshark on a wpan and lowpan
interface.

Signed-off-by: Alexander Aring <alex.aring@gmail.com>
---
 net/6lowpan/iphc.c | 290 +++++++++++++++++++++++++++++++++++++----------------
 1 file changed, 205 insertions(+), 85 deletions(-)

diff --git a/net/6lowpan/iphc.c b/net/6lowpan/iphc.c
index af8af98..e6cdfc9 100644
--- a/net/6lowpan/iphc.c
+++ b/net/6lowpan/iphc.c
@@ -346,6 +346,108 @@ static int lowpan_uncompress_multicast_daddr(struct sk_buff *skb,
 	return 0;
 }
 
+/* get the ecn values from iphc tf format and set it to ipv6hdr */
+static inline void lowpan_iphc_tf_set_ecn(struct ipv6hdr *hdr, const u8 *tf)
+{
+	/* get the two higher bits which is ecn */
+	u8 ecn = tf[0] & 0xc0;
+
+	/* ECN takes 0x30 in hdr->flow_lbl[0] */
+	hdr->flow_lbl[0] |= (ecn >> 2);
+}
+
+/* get the dscp values from iphc tf format and set it to ipv6hdr */
+static inline void lowpan_iphc_tf_set_dscp(struct ipv6hdr *hdr, const u8 *tf)
+{
+	/* DSCP is at place after ECN */
+	u8 dscp = tf[0] & 0x3f;
+
+	/* The four highest bits need to be set at hdr->priority */
+	hdr->priority |= ((dscp & 0x3c) >> 2);
+	/* The two lower bits is part of hdr->flow_lbl[0] */
+	hdr->flow_lbl[0] |= ((dscp & 0x03) << 6);
+}
+
+/* get the flow label values from iphc tf format and set it to ipv6hdr */
+static inline void lowpan_iphc_tf_set_lbl(struct ipv6hdr *hdr, const u8 *lbl)
+{
+	/* flow label is always some array started with lower nibble of
+	 * flow_lbl[0] and followed with two bytes afterwards. Inside inline
+	 * data the flow_lbl position can be different, which will be handled
+	 * by lbl pointer. E.g. case "01" vs "00" the traffic class is 8 bit
+	 * shifted, the different lbl pointer will handle that.
+	 *
+	 * The flow label will started at lower nibble of flow_lbl[0], the
+	 * higher nibbles are part of DSCP + ECN.
+	 */
+	hdr->flow_lbl[0] |= lbl[0] & 0x0f;
+	memcpy(&hdr->flow_lbl[1], &lbl[1], 2);
+}
+
+/* lowpan_iphc_tf_decompress - decompress the traffic class.
+ *	This function will return zero on success, a value lower than zero if
+ *	failed.
+ */
+static int lowpan_iphc_tf_decompress(struct sk_buff *skb, struct ipv6hdr *hdr,
+				     u8 val)
+{
+	u8 tf[4];
+
+	/* Traffic Class and Flow Label */
+	switch (val) {
+	case LOWPAN_IPHC_TF_00:
+		/* ECN + DSCP + 4-bit Pad + Flow Label (4 bytes) */
+		if (lowpan_fetch_skb(skb, tf, 4))
+			return -EINVAL;
+
+		/*                      1                   2                   3
+		 *  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+		 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+		 * |ECN|   DSCP    |  rsv  |             Flow Label                |
+		 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+		 */
+		lowpan_iphc_tf_set_ecn(hdr, tf);
+		lowpan_iphc_tf_set_dscp(hdr, tf);
+		lowpan_iphc_tf_set_lbl(hdr, &tf[1]);
+		break;
+	case LOWPAN_IPHC_TF_01:
+		/* ECN + 2-bit Pad + Flow Label (3 bytes), DSCP is elided. */
+		if (lowpan_fetch_skb(skb, tf, 3))
+			return -EINVAL;
+
+		/*                     1                   2
+		 * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3
+		 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+		 * |ECN|rsv|             Flow Label                |
+		 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+		 */
+		lowpan_iphc_tf_set_ecn(hdr, tf);
+		lowpan_iphc_tf_set_lbl(hdr, &tf[0]);
+		break;
+	case LOWPAN_IPHC_TF_10:
+		/* ECN + DSCP (1 byte), Flow Label is elided. */
+		if (lowpan_fetch_skb(skb, tf, 1))
+			return -EINVAL;
+
+		/*  0 1 2 3 4 5 6 7
+		 * +-+-+-+-+-+-+-+-+
+		 * |ECN|   DSCP    |
+		 * +-+-+-+-+-+-+-+-+
+		 */
+		lowpan_iphc_tf_set_ecn(hdr, tf);
+		lowpan_iphc_tf_set_dscp(hdr, tf);
+		break;
+	case LOWPAN_IPHC_TF_11:
+		/* Traffic Class and Flow Label are elided */
+		break;
+	default:
+		WARN_ON_ONCE(1);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
 /* TTL uncompression values */
 static const u8 lowpan_ttl_values[] = {
 	[LOWPAN_IPHC_HLIM_01] = 1,
@@ -357,7 +459,7 @@ int lowpan_header_decompress(struct sk_buff *skb, const struct net_device *dev,
 			     const void *daddr, const void *saddr)
 {
 	struct ipv6hdr hdr = {};
-	u8 iphc0, iphc1, tmp = 0;
+	u8 iphc0, iphc1;
 	int err;
 
 	raw_dump_table(__func__, "raw skb data dump uncompressed",
@@ -373,49 +475,10 @@ int lowpan_header_decompress(struct sk_buff *skb, const struct net_device *dev,
 
 	hdr.version = 6;
 
-	/* Traffic Class and Flow Label */
-	switch (iphc0 & LOWPAN_IPHC_TF_MASK) {
-	/* Traffic Class and FLow Label carried in-line
-	 * ECN + DSCP + 4-bit Pad + Flow Label (4 bytes)
-	 */
-	case LOWPAN_IPHC_TF_00:
-		if (lowpan_fetch_skb(skb, &tmp, sizeof(tmp)))
-			return -EINVAL;
-
-		memcpy(&hdr.flow_lbl, &skb->data[0], 3);
-		skb_pull(skb, 3);
-		hdr.priority = ((tmp >> 2) & 0x0f);
-		hdr.flow_lbl[0] = ((tmp >> 2) & 0x30) | (tmp << 6) |
-					(hdr.flow_lbl[0] & 0x0f);
-		break;
-	/* Flow Label carried in-line
-	 * ECN + 2-bit Pad + Flow Label (3 bytes), DSCP is elided
-	 */
-	case LOWPAN_IPHC_TF_01:
-		if (lowpan_fetch_skb(skb, &tmp, sizeof(tmp)))
-			return -EINVAL;
-
-		hdr.flow_lbl[0] = (tmp & 0x0F) | ((tmp >> 2) & 0x30);
-		memcpy(&hdr.flow_lbl[1], &skb->data[0], 2);
-		skb_pull(skb, 2);
-		break;
-	/* Traffic class carried in-line
-	 * ECN + DSCP (1 byte), Flow Label is elided
-	 */
-	case LOWPAN_IPHC_TF_10:
-		if (lowpan_fetch_skb(skb, &tmp, sizeof(tmp)))
-			return -EINVAL;
-
-		hdr.priority = ((tmp >> 2) & 0x0f);
-		hdr.flow_lbl[0] = ((tmp << 6) & 0xC0) | ((tmp >> 2) & 0x30);
-		break;
-	/* Traffic Class and Flow Label are elided */
-	case LOWPAN_IPHC_TF_11:
-		break;
-	default:
-		WARN_ON_ONCE(1);
-		break;
-	}
+	err = lowpan_iphc_tf_decompress(skb, &hdr,
+					iphc0 & LOWPAN_IPHC_TF_MASK);
+	if (err < 0)
+		return err;
 
 	/* Next Header */
 	if (!(iphc0 & LOWPAN_IPHC_NH)) {
@@ -550,10 +613,105 @@ static u8 lowpan_compress_addr_64(u8 **hc_ptr, const struct in6_addr *ipaddr,
 		return dam;
 }
 
+/* lowpan_iphc_get_tc - get the ECN + DCSP fields in hc format */
+static inline u8 lowpan_iphc_get_tc(const struct ipv6hdr *hdr)
+{
+	u8 dscp, ecn;
+
+	/* hdr->priority contains the higher bits of dscp, lower are part of
+	 * flow_lbl[0]. Note ECN, DCSP is swapped in ipv6 hdr.
+	 */
+	dscp = (hdr->priority << 2) | ((hdr->flow_lbl[0] & 0xc0) >> 6);
+	/* ECN is at the two lower bits from first nibble of flow_lbl[0] */
+	ecn = (hdr->flow_lbl[0] & 0x30);
+	/* for pretty debug output, also shift ecn to get the ecn value */
+	pr_debug("ecn 0x%02x dscp 0x%02x\n", ecn >> 4, dscp);
+	/* ECN is at 0x30 now, shift it to have ECN + DCSP */
+	return (ecn << 2) | dscp;
+}
+
+/* lowpan_iphc_is_flow_lbl_zero - check if flow label is zero */
+static inline bool lowpan_iphc_is_flow_lbl_zero(const struct ipv6hdr *hdr)
+{
+	return ((!(hdr->flow_lbl[0] & 0x0f)) &&
+		!hdr->flow_lbl[1] && !hdr->flow_lbl[2]);
+}
+
+/* lowpan_iphc_tf_compress - compress the traffic class which is set by
+ *	ipv6hdr. Return the corresponding format identifier which is used.
+ */
+static u8 lowpan_iphc_tf_compress(u8 **hc_ptr, const struct ipv6hdr *hdr)
+{
+	/* get ecn dscp data in a byteformat as: ECN(hi) + DSCP(lo) */
+	u8 tc = lowpan_iphc_get_tc(hdr), tf[4], val;
+
+	/* printout the traffic class in hc format */
+	pr_debug("tc 0x%02x\n", tc);
+
+	if (lowpan_iphc_is_flow_lbl_zero(hdr)) {
+		if (!tc) {
+			/* 11:  Traffic Class and Flow Label are elided. */
+			val = LOWPAN_IPHC_TF_11;
+		} else {
+			/* 10:  ECN + DSCP (1 byte), Flow Label is elided.
+			 *
+			 *  0 1 2 3 4 5 6 7
+			 * +-+-+-+-+-+-+-+-+
+			 * |ECN|   DSCP    |
+			 * +-+-+-+-+-+-+-+-+
+			 */
+			lowpan_push_hc_data(hc_ptr, &tc, sizeof(tc));
+			val = LOWPAN_IPHC_TF_10;
+		}
+	} else {
+		/* check if dscp is zero, it's after the first two bit */
+		if (!(tc & 0x3f)) {
+			/* 01:  ECN + 2-bit Pad + Flow Label (3 bytes), DSCP is elided
+			 *
+			 *                     1                   2
+			 * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3
+			 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+			 * |ECN|rsv|             Flow Label                |
+			 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+			 */
+			memcpy(&tf[0], &hdr->flow_lbl[0], 3);
+			/* zero the highest 4-bits, contains DCSP + ECN */
+			tf[0] &= ~0xf0;
+			/* set ECN */
+			tf[0] |= (tc & 0xc0);
+
+			lowpan_push_hc_data(hc_ptr, tf, 3);
+			val = LOWPAN_IPHC_TF_01;
+		} else {
+			/* 00:  ECN + DSCP + 4-bit Pad + Flow Label (4 bytes)
+			 *
+			 *                      1                   2                   3
+			 *  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+			 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+			 * |ECN|   DSCP    |  rsv  |             Flow Label                |
+			 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+			 */
+			memcpy(&tf[0], &tc, sizeof(tc));
+			/* highest nibble of flow_lbl[0] is part of DSCP + ECN
+			 * which will be the 4-bit pad and will be filled with
+			 * zeros afterwards.
+			 */
+			memcpy(&tf[1], &hdr->flow_lbl[0], 3);
+			/* zero the 4-bit pad, which is reserved */
+			tf[1] &= ~0xf0;
+
+			lowpan_push_hc_data(hc_ptr, tf, 4);
+			val = LOWPAN_IPHC_TF_00;
+		}
+	}
+
+	return val;
+}
+
 int lowpan_header_compress(struct sk_buff *skb, const struct net_device *dev,
 			   const void *daddr, const void *saddr)
 {
-	u8 tmp, iphc0, iphc1, *hc_ptr;
+	u8 iphc0, iphc1, *hc_ptr;
 	struct ipv6hdr *hdr;
 	u8 head[LOWPAN_IPHC_MAX_HC_BUF_LEN] = {};
 	int ret, addr_type;
@@ -588,46 +746,8 @@ int lowpan_header_compress(struct sk_buff *skb, const struct net_device *dev,
 	raw_dump_table(__func__, "sending raw skb network uncompressed packet",
 		       skb->data, skb->len);
 
-	/* Traffic class, flow label
-	 * If flow label is 0, compress it. If traffic class is 0, compress it
-	 * We have to process both in the same time as the offset of traffic
-	 * class depends on the presence of version and flow label
-	 */
-
-	/* hc format of TC is ECN | DSCP , original one is DSCP | ECN */
-	tmp = (hdr->priority << 4) | (hdr->flow_lbl[0] >> 4);
-	tmp = ((tmp & 0x03) << 6) | (tmp >> 2);
-
-	if (((hdr->flow_lbl[0] & 0x0F) == 0) &&
-	    (hdr->flow_lbl[1] == 0) && (hdr->flow_lbl[2] == 0)) {
-		/* flow label can be compressed */
-		iphc0 |= LOWPAN_IPHC_TF_10;
-		if ((hdr->priority == 0) &&
-		    ((hdr->flow_lbl[0] & 0xF0) == 0)) {
-			/* compress (elide) all */
-			iphc0 |= LOWPAN_IPHC_TF_11;
-		} else {
-			/* compress only the flow label */
-			*hc_ptr = tmp;
-			hc_ptr += 1;
-		}
-	} else {
-		/* Flow label cannot be compressed */
-		if ((hdr->priority == 0) &&
-		    ((hdr->flow_lbl[0] & 0xF0) == 0)) {
-			/* compress only traffic class */
-			iphc0 |= LOWPAN_IPHC_TF_01;
-			*hc_ptr = (tmp & 0xc0) | (hdr->flow_lbl[0] & 0x0F);
-			memcpy(hc_ptr + 1, &hdr->flow_lbl[1], 2);
-			hc_ptr += 3;
-		} else {
-			/* compress nothing */
-			memcpy(hc_ptr, hdr, 4);
-			/* replace the top byte with new ECN | DSCP format */
-			*hc_ptr = tmp;
-			hc_ptr += 4;
-		}
-	}
+	/* Traffic Class, Flow Label compression */
+	iphc0 |= lowpan_iphc_tf_compress(&hc_ptr, hdr);
 
 	/* NOTE: payload length is always compressed */
 
-- 
2.6.1

[PATCH bluetooth-next 6/6] 6lowpan: put mcast compression in an own function

[Alexander Aring]

This patch moves the mcast compression algorithmn to an own function
like all other compression/decompression methods in iphc.

Signed-off-by: Alexander Aring <alex.aring@gmail.com>
---
 net/6lowpan/iphc.c | 59 +++++++++++++++++++++++++++++-------------------------
 1 file changed, 32 insertions(+), 27 deletions(-)

diff --git a/net/6lowpan/iphc.c b/net/6lowpan/iphc.c
index e6cdfc9..346b5c1 100644
--- a/net/6lowpan/iphc.c
+++ b/net/6lowpan/iphc.c
@@ -708,6 +708,37 @@ static u8 lowpan_iphc_tf_compress(u8 **hc_ptr, const struct ipv6hdr *hdr)
 	return val;
 }
 
+static u8 lowpan_iphc_mcast_addr_compress(u8 **hc_ptr,
+					  const struct in6_addr *ipaddr)
+{
+	u8 val;
+
+	if (lowpan_is_mcast_addr_compressable8(ipaddr)) {
+		pr_debug("compressed to 1 octet\n");
+		/* use last byte */
+		lowpan_push_hc_data(hc_ptr, &ipaddr->s6_addr[15], 1);
+		val = LOWPAN_IPHC_DAM_11;
+	} else if (lowpan_is_mcast_addr_compressable32(ipaddr)) {
+		pr_debug("compressed to 4 octets\n");
+		/* second byte + the last three */
+		lowpan_push_hc_data(hc_ptr, &ipaddr->s6_addr[1], 1);
+		lowpan_push_hc_data(hc_ptr, &ipaddr->s6_addr[13], 3);
+		val = LOWPAN_IPHC_DAM_10;
+	} else if (lowpan_is_mcast_addr_compressable48(ipaddr)) {
+		pr_debug("compressed to 6 octets\n");
+		/* second byte + the last five */
+		lowpan_push_hc_data(hc_ptr, &ipaddr->s6_addr[1], 1);
+		lowpan_push_hc_data(hc_ptr, &ipaddr->s6_addr[11], 5);
+		val = LOWPAN_IPHC_DAM_01;
+	} else {
+		pr_debug("using full address\n");
+		lowpan_push_hc_data(hc_ptr, ipaddr->s6_addr, 16);
+		val = LOWPAN_IPHC_DAM_00;
+	}
+
+	return val;
+}
+
 int lowpan_header_compress(struct sk_buff *skb, const struct net_device *dev,
 			   const void *daddr, const void *saddr)
 {
@@ -804,33 +835,7 @@ int lowpan_header_compress(struct sk_buff *skb, const struct net_device *dev,
 	if (addr_type & IPV6_ADDR_MULTICAST) {
 		pr_debug("destination address is multicast: ");
 		iphc1 |= LOWPAN_IPHC_M;
-		if (lowpan_is_mcast_addr_compressable8(&hdr->daddr)) {
-			pr_debug("compressed to 1 octet\n");
-			iphc1 |= LOWPAN_IPHC_DAM_11;
-			/* use last byte */
-			lowpan_push_hc_data(&hc_ptr,
-					    &hdr->daddr.s6_addr[15], 1);
-		} else if (lowpan_is_mcast_addr_compressable32(&hdr->daddr)) {
-			pr_debug("compressed to 4 octets\n");
-			iphc1 |= LOWPAN_IPHC_DAM_10;
-			/* second byte + the last three */
-			lowpan_push_hc_data(&hc_ptr,
-					    &hdr->daddr.s6_addr[1], 1);
-			lowpan_push_hc_data(&hc_ptr,
-					    &hdr->daddr.s6_addr[13], 3);
-		} else if (lowpan_is_mcast_addr_compressable48(&hdr->daddr)) {
-			pr_debug("compressed to 6 octets\n");
-			iphc1 |= LOWPAN_IPHC_DAM_01;
-			/* second byte + the last five */
-			lowpan_push_hc_data(&hc_ptr,
-					    &hdr->daddr.s6_addr[1], 1);
-			lowpan_push_hc_data(&hc_ptr,
-					    &hdr->daddr.s6_addr[11], 5);
-		} else {
-			pr_debug("using full address\n");
-			iphc1 |= LOWPAN_IPHC_DAM_00;
-			lowpan_push_hc_data(&hc_ptr, hdr->daddr.s6_addr, 16);
-		}
+		iphc1 |= lowpan_iphc_mcast_addr_compress(&hc_ptr, &hdr->daddr);
 	} else {
 		if (addr_type & IPV6_ADDR_LINKLOCAL) {
 			/* TODO: context lookup */
-- 
2.6.1

Re: [PATCH bluetooth-next 0/6] 6lowpan: iphc defines and rework tc and flow label handling

[Marcel Holtmann]

Hi Alex,

> this patch series based on my previous series "[PATCH bluetooth-next 1/6]
> mac802154: llsec: use kzfree" and contains changes for iphc defines and
> reworking the tc/flow label handling.
> 
> I tested the tc/flow label handling with fakelb and wireshark. So it should
> be wrong, when wireshark is wrong also. I hope wireshark has some correct
> mechanism to handle it. I used "wireshark 1.12.7".
> 
> - Alex
> 
> Alexander Aring (6):
>  6lowpan: nhc: move iphc manipulation out of nhc
>  6lowpan: move IPHC functionality defines
>  6lowpan: remove lowpan_is_addr_broadcast
>  6lowpan: iphc: change define values
>  6lowpan: rework tc and flow label handling
>  6lowpan: put mcast compression in an own function
> 
> include/net/6lowpan.h       | 133 -----------
> net/6lowpan/iphc.c          | 565 +++++++++++++++++++++++++++++++-------------
> net/6lowpan/nhc.c           |  13 +-
> net/6lowpan/nhc.h           |   9 +-
> net/6lowpan/nhc_udp.c       |  22 +-
> net/ieee802154/6lowpan/tx.c |   5 +-
> 6 files changed, 430 insertions(+), 317 deletions(-)

all 6 patches have been applied to bluetooth-next tree.

Regards

Marcel