linux-toradex.git/include/linux/skbuff.h, branch v2.6.23.14

Fix SKB_WITH_OVERHEAD calculations.

2007-11-16T16:27:36+00:00

patch deea84b0ae3d26b41502ae0a39fe7fe134e703d0 in mainline.

[NET]: Fix SKB_WITH_OVERHEAD calculation

The calculation in SKB_WITH_OVERHEAD is incorrect in that it can cause
an overflow across a page boundary which is what it's meant to prevent.
In particular, the header length (X) should not be lumped together with
skb_shared_info.  The latter needs to be aligned properly while the header
has no choice but to sit in front of wherever the payload is.

Therefore the correct calculation is to take away the aligned size of
skb_shared_info, and then subtract the header length.  The resulting
quantity L satisfies the following inequality:

	SKB_DATA_ALIGN(L + X) + sizeof(struct skb_shared_info) <= PAGE_SIZE

This is the quantity used by alloc_skb to do the actual allocation.

Signed-off-by: Herbert Xu 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

[NET] skbuff: Add skb_cow_head

2007-09-16T23:21:16+00:00

This patch adds an optimised version of skb_cow that avoids the copy if
the header can be modified even if the rest of the payload is cloned.

This can be used in encapsulating paths where we only need to modify the
header.  As it is, this can be used in PPPOE and bridging.

Signed-off-by: Herbert Xu 
Signed-off-by: David S. Miller

[NET]: Page offsets and lengths need to be __u32.

2007-07-31T09:28:28+00:00

Based upon a report from Stephen Rothwell.

Signed-off-by: David S. Miller

fix return type of skb_checksum_complete()

2007-07-15T23:40:51+00:00

It returns __sum16, not unsigned int

Signed-off-by: Al Viro 
Signed-off-by: Linus Torvalds

[NET]: Update comments for skb checksums

2007-07-11T05:41:55+00:00

Rusty (whose comments we should all study and emulate :) pointed
out that our comments for skb checksums are no longer up-to-date.
So here is a patch to

1) add the case of partial checksums on input;
2) update partial checksum case to mention csum_start/csum_offset;
3) mention the new IPv6 feature bit.

Signed-off-by: Herbert Xu 
Signed-off-by: David S. Miller

[NETFILTER]: x_tables: add TRACE target

2007-07-11T05:17:14+00:00

The TRACE target can be used to follow IP and IPv6 packets through
the ruleset.

Signed-off-by: Jozsef Kadlecsik 
Signed-off-by: Patrick NcHardy 
Signed-off-by: David S. Miller

[CORE] Stack changes to add multiqueue hardware support API

2007-07-11T05:16:21+00:00

Add the multiqueue hardware device support API to the core network
stack.  Allow drivers to allocate multiple queues and manage them at
the netdev level if they choose to do so.

Added a new field to sk_buff, namely queue_mapping, for drivers to
know which tx_ring to select based on OS classification of the flow.

Signed-off-by: Peter P Waskiewicz Jr 
Signed-off-by: Patrick McHardy 
Signed-off-by: David S. Miller

[SKBUFF]: Keep track of writable header len of headerless clones

2007-07-11T05:15:37+00:00

Currently NAT (and others) that want to modify cloned skbs copy them,
even if in the vast majority of cases its not necessary because the
skb is a clone made by TCP and the portion NAT wants to modify is
actually writable because TCP release the header reference before
cloning.

The problem is that there is no clean way for NAT to find out how
long the writable header area is, so this patch introduces skb->hdr_len
to hold this length. When a headerless skb is cloned skb->hdr_len
is set to the current headroom, for regular clones it is copied from
the original. A new function skb_clone_writable(skb, len) returns
whether the skb is writable up to len bytes from skb->data. To avoid
enlarging the skb the mac_len field is reduced to 16 bit and the
new hdr_len field is put in the remaining 16 bit.

I've done a few rough benchmarks of NAT (not with this exact patch,
but a very similar one). As expected it saves huge amounts of system
time in case of sendfile, bringing it down to basically the same
amount as without NAT, with sendmsg it only helps on loopback,
probably because of the large MTU.

Transmit a 1GB file using sendfile/sendmsg over eth0/lo with and
without NAT:

- sendfile eth0, no NAT:	sys     0m0.388s
- sendfile eth0, NAT:		sys     0m1.835s
- sendfile eth0: NAT + path:	sys     0m0.370s	(~ -80%)

- sendfile lo, no NAT:		sys     0m0.258s
- sendfile lo, NAT:		sys     0m2.609s
- sendfile lo, NAT + patch:	sys     0m0.260s	(~ -90%)

- sendmsg eth0, no NAT:		sys     0m2.508s
- sendmsg eth0, NAT:		sys     0m2.539s
- sendmsg eth0, NAT + patch:	sys     0m2.445s	(no change)

- sendmsg lo, no NAT:		sys	0m2.151s
- sendmsg lo, NAT:		sys     0m3.557s
- sendmsg lo, NAT + patch:	sys     0m2.159s	(~ -40%)

I expect other users can see a similar performance improvement,
packet mangling iptables targets, ipip and ip_gre come to mind ..

Signed-off-by: Patrick McHardy 
Signed-off-by: David S. Miller

[TCP]: Congestion control API RTT sampling fix

2007-06-15T22:08:43+00:00

Commit 164891aadf1721fca4dce473bb0e0998181537c6 broke RTT
sampling of congestion control modules. Inaccurate timestamps
could be fed to them without providing any way for them to
identify such cases. Previously RTT sampler was called only if
FLAG_RETRANS_DATA_ACKED was not set filtering inaccurate
timestamps nicely. In addition, the new behavior could give an
invalid timestamp (zero) to RTT sampler if only skbs with
TCPCB_RETRANS were ACKed. This solves both problems.

Signed-off-by: Ilpo Järvinen 
Signed-off-by: David S. Miller

[NET] skbuff: fix kernel-doc

2007-05-03T10:16:20+00:00

Fix skbuff.h kernel-doc:
linux-2.6.21-git4//include/linux/skbuff.h:316): No description found for parameter 'transport_header'

Signed-off-by: Randy Dunlap 
Signed-off-by: David S. Miller