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ieee802154: change needed headroom/tailroom

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This patch cleanups needed_headroom, needed_tailroom and hard_header_len
fields for wpan and lowpan interfaces.

For wpan interfaces the worst case mac header len should be part of
needed_headroom, currently this is set as hard_header_len, but
hard_header_len should be set to the minimum header length which xmit
call assumes and this is the minimum frame length of 802.15.4.
The hard_header_len value will check inside send callbacl of AF_PACKET
raw sockets.

For lowpan interfaces, if fragmentation isn't needed the skb will
call dev_hard_header for 802154 layer and queue it afterwards. This
happens without new skb allocation, so we need the same headroom and
tailroom lengths like 802154 inside 802154 6lowpan layer. At least we
assume as minimum header length an ipv6 header size.

Signed-off-by: Alexander Aring <alex.aring@gmail.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
This commit is contained in:
Alexander Aring
2015-09-18 11:30:43 +02:00
committed by Marcel Holtmann
parent 838b83d63d
commit 87a93e4ece
9 changed files with 55 additions and 22 deletions
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8
include/net/6lowpan.h
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@ -61,6 +61,14 @@
#define UIP_PROTO_UDP 17 /* ipv6 next header value for UDP */
#define UIP_FRAGH_LEN 8 /* ipv6 fragment header size */
#define LOWPAN_NHC_MAX_ID_LEN 1
/* Max IPHC Header len without IPv6 hdr specific inline data.
* Useful for getting the "extra" bytes we need at worst case compression.
*
* LOWPAN_IPHC + CID + LOWPAN_NHC_MAX_ID_LEN
*/
#define LOWPAN_IPHC_MAX_HEADER_LEN (2 + 1 + LOWPAN_NHC_MAX_ID_LEN)
/*
* ipv6 address based on mac
* second bit-flip (Universe/Local) is done according RFC2464