A long time ago we had bugs, primarily in TCP, where we would modify
skb->truesize (for TSO queue collapsing) in ways which would corrupt
the socket memory accounting.
skb_truesize_check() was added in order to try and catch this error
more systematically.
However this debugging check has morphed into a Frankenstein of sorts
and these days it does nothing other than catch false-positives.
Signed-off-by: David S. Miller <davem@davemloft.net>
The additional per-packet information (16 bytes for time stamps, 1
byte for flags) is stored for all packets in the skb_shared_info
struct. This implementation detail is hidden from users of that
information via skb_* accessor functions. A separate struct resp.
union is used for the additional information so that it can be
stored/copied easily outside of skb_shared_info.
Compared to previous implementations (reusing the tstamp field
depending on the context, optional additional structures) this
is the simplest solution. It does not extend sk_buff itself.
TX time stamping is implemented in software if the device driver
doesn't support hardware time stamping.
The new semantic for hardware/software time stamping around
ndo_start_xmit() is based on two assumptions about existing
network device drivers which don't support hardware time
stamping and know nothing about it:
- they leave the new skb_shared_tx unmodified
- the keep the connection to the originating socket in skb->sk
alive, i.e., don't call skb_orphan()
Given that skb_shared_tx is new, the first assumption is safe.
The second is only true for some drivers. As a result, software
TX time stamping currently works with the bnx2 driver, but not
with the unmodified igb driver (the two drivers this patch series
was tested with).
Signed-off-by: Patrick Ohly <patrick.ohly@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
struct page walking should be done with proper accessor functions, not
directly.
With doubts from David S. Miller and Herbert Xu.
Signed-off-by: Jarek Poplawski <jarkao2@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
net/core/skbuff.c is a hodge-podge of symbol export placement.
Some of the exports are right after the definition of the
symbol being exported, others are clumped together into a big
group at the end of the file.
Make things consistent.
Signed-off-by: David S. Miller <davem@davemloft.net>
The previous fix ad0f990444 (gro:
Fix handling of imprecisely split packets) only fixed the case
of frags merging, frag_list merging in the same circumstances
were still broken.
In particular, the packet headers end up in the data stream.
This patch fixes this plus another issue where an imprecisely
split packet header may be read incorrectly (this is mostly
harmless since it'll simply cause the packet to not match and
be rejected for GRO).
Thanks to Emil Tantilov and Jeff Kirsher for helping to track
this down.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
The recent fix of data corruption when splicing from sockets uses
memory very inefficiently allocating a new page to copy each chunk of
linear part of skb. This patch uses the same page until it's full
(almost) by caching the page in sk_sndmsg_page field.
With changes from David S. Miller <davem@davemloft.net>
Signed-off-by: Jarek Poplawski <jarkao2@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
gro: Do not merge paged packets into frag_list
Bigger is not always better :)
It was easy to continue to merged packets into frag_list after the
page array is full. However, this turns out to be worse than LRO
because frag_list is a much less efficient form of storage than the
page array. So we're better off stopping the merge and starting
a new entry with an empty page array.
In future we can optimise this further by doing frag_list merging
but making sure that we continue to fill in the page array.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
Unfortunately simplicity isn't always the best. The fraginfo
interface turned out to be suboptimal. The problem was quite
obvious. For every packet, we have to copy the headers from
the frags structure into skb->head, even though for 99% of the
packets this part is immediately thrown away after the merge.
LRO didn't have this problem because it directly read the headers
from the frags structure.
This patch attempts to address this by creating an interface
that allows GRO to access the headers in the first frag without
having to copy it. Because all drivers that use frags place the
headers in the first frag this optimisation should be enough.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
It oopsd for me in skb_seq_read. addr2line said it was
linux-2.6/net/core/skbuff.c:2228, which is this line:
while (st->frag_idx < skb_shinfo(st->cur_skb)->nr_frags) {
I added some printks in there and it looks like we hit this:
} else if (st->root_skb == st->cur_skb &&
skb_shinfo(st->root_skb)->frag_list) {
st->cur_skb = skb_shinfo(st->root_skb)->frag_list;
st->frag_idx = 0;
goto next_skb;
}
Actually I did some testing and added a few printks and found that the
st->cur_skb->data was 0 and hence the ptr used by iscsi_tcp was null.
This caused the kernel panic.
if (abs_offset < block_limit) {
- *data = st->cur_skb->data + abs_offset;
+ *data = st->cur_skb->data + (abs_offset - st->stepped_offset);
I enabled the debug_tcp and with a few printks found that the code did
not go to the next_skb label and could find that the sequence being
followed was this -
It hit this if condition -
if (st->cur_skb->next) {
st->cur_skb = st->cur_skb->next;
st->frag_idx = 0;
goto next_skb;
And so, now the st pointer is shifted to the next skb whereas actually
it should have hit the second else if first since the data is in the
frag_list.
else if (st->root_skb == st->cur_skb &&
skb_shinfo(st->root_skb)->frag_list) {
st->cur_skb = skb_shinfo(st->root_skb)->frag_list;
goto next_skb;
}
Reversing the two conditions the attached patch fixes the issue for me
on top of Herbert's patches.
Signed-off-by: Shyam Iyer <shyam_iyer@dell.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
The frag_list handling was broken in skb_seq_read:
1) We didn't add the stepped offset when looking at the head
are of fragments other than the first.
2) We didn't take the stepped offset away when setting the data
pointer in the head area.
3) The frag index wasn't reset.
This patch fixes both issues.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
The previous fix to paged packets broke the merging because it
reset the skb->len before we added it to the merged packet. This
wasn't detected because it simply resulted in the truncation of
the packet while the missing bit is subsequently retransmitted.
The fix is to store skb->len before we clobber it.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
The trick in socket splicing where we try to convert the skb->data
into a page based reference using virt_to_page() does not work so
well.
The idea is to pass the virt_to_page() reference via the pipe
buffer, and refcount the buffer using a SKB reference.
But if we are splicing from a socket to a socket (via sendpage)
this doesn't work.
The from side processing will grab the page (and SKB) references.
The sendpage() calls will grab page references only, return, and
then the from side processing completes and drops the SKB ref.
The page based reference to skb->data is not enough to keep the
kmalloc() buffer backing it from being reused. Yet, that is
all that the socket send side has at this point.
This leads to data corruption if the skb->data buffer is reused
by SLAB before the send side socket actually gets the TX packet
out to the device.
The fix employed here is to simply allocate a page and copy the
skb->data bytes into that page.
This will hurt performance, but there is no clear way to fix this
properly without a copy at the present time, and it is important
to get rid of the data corruption.
With fixes from Herbert Xu.
Tested-by: Willy Tarreau <w@1wt.eu>
Foreseen-by: Changli Gao <xiaosuo@gmail.com>
Diagnosed-by: Willy Tarreau <w@1wt.eu>
Reported-by: Willy Tarreau <w@1wt.eu>
Fixed-by: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Jarek Poplawski <jarkao2@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
When an skb with page frags is merged into an existing one, we
cannibalise its reference count. This is OK when the skb is
reused because we set nr_frags to zero in that case. However,
for the case where the skb is freed through kfree_skb, we didn't
clear nr_frags which causes the page to be freed prematurely.
This is fixed by moving the skb resetting into skb_gro_receive.
Reported-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch allows GRO to merge page frags (skb_shinfo(skb)->frags)
in one skb, rather than using the less efficient frag_list.
It also adds a new interface, napi_gro_frags to allow drivers
to inject page frags directly into the stack without allocating
an skb. This is intended to be the GRO equivalent for LRO's
lro_receive_frags interface.
The existing GSO interface can already handle page frags with
or without an appended frag_list so nothing needs to be changed
there.
The merging itself is rather simple. We store any new frag entries
after the last existing entry, without checking whether the first
new entry can be merged with the last existing entry. Making this
check would actually be easy but since no existing driver can
produce contiguous frags anyway it would just be mental masturbation.
If the total number of entries would exceed the capacity of a
single skb, we simply resort to using frag_list as we do now.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
In order to allow GRO packets without frag_list at all, we need to
store the MSS in the packet itself. The obvious place is gso_size.
The only thing to watch out for is if the packet ends up not being
GRO then we need to clear gso_size before pushing the packet into
the stack.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch adds the helper skb_gro_receive to merge packets for
GRO. The current method is to allocate a new header skb and then
chain the original packets to its frag_list. This is done to
make it easier to integrate into the existing GSO framework.
In future as GSO is moved into the drivers, we can undo this and
simply chain the original packets together.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch adds limited support for handling frag_list packets in
skb_segment. The intention is to support GRO (Generic Receive Offload)
packets which will be constructed by chaining normal packets using
frag_list.
As such we require all frag_list members terminate on exact MSS
boundaries. This is checked using BUG_ON.
As there should only be one producer in the kernel of such packets,
namely GRO, this requirement should not be difficult to maintain.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
The truesize message check is important enough to make it print "BUG"
to the user console... lets also make it important enough to spit a
backtrace/module list etc so that kerneloops.org can track them.
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Since pskb_expand_head creates copy of the shared area we
cannot keep any frag ptr past de-cloning. This fixes the
tcpdump recvfrom -EFAULT problem.
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
This caused me to get repeatably:
tcpdump: pcap_loop: recvfrom: Bad address
Happens occassionally when I tcpdump my for-looped test xfers:
while [ : ]; do echo -n "$(date '+%s.%N') "; ./sendfile; sleep 20; done
Rest of the relevant commands:
ethtool -K eth0 tso off
tc qdisc add dev eth0 root netem drop 4%
tcpdump -n -s0 -i eth0 -w sacklog.all
Running net-next under kvm, connection goes to the same host
(basically just out of kvm). The connection itself works ok
and data gets sent without corruption even with a large
number of tests while tcpdump fails usually within less than
5 tests.
Whether it only happens because of this change or not, I
don't know for sure but it's the only thing with which
I've seen that error. The non-cloned variant works w/o it
for much longer time. I'm yet to debug where the error
actually comes from.
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
During SACK processing, most of the benefits of TSO are eaten by
the SACK blocks that one-by-one fragment SKBs to MSS sized chunks.
Then we're in problems when cleanup work for them has to be done
when a large cumulative ACK comes. Try to return back to pre-split
state already while more and more SACK info gets discovered by
combining newly discovered SACK areas with the previous skb if
that's SACKed as well.
This approach has a number of benefits:
1) The processing overhead is spread more equally over the RTT
2) Write queue has less skbs to process (affect everything
which has to walk in the queue past the sacked areas)
3) Write queue is consistent whole the time, so no other parts
of TCP has to be aware of this (this was not the case with
some other approach that was, well, quite intrusive all
around).
4) Clean_rtx_queue can release most of the pages using single
put_page instead of previous PAGE_SIZE/mss+1 calls
In case a hole is fully filled by the new SACK block, we attempt
to combine the next skb too which allows construction of skbs
that are even larger than what tso split them to and it handles
hole per on every nth patterns that often occur during slow start
overshoot pretty nicely. Though this to be really useful also
a retransmission would have to get lost since cumulative ACKs
advance one hole at a time in the most typical case.
TODO: handle upwards only merging. That should be rather easy
when segment is fully sacked but I'm leaving that as future
work item (it won't make very large difference anyway since
this current approach already covers quite a lot of normal
cases).
I was earlier thinking of some sophisticated way of tracking
timestamps of the first and the last segment but later on
realized that it won't be that necessary at all to store the
timestamp of the last segment. The cases that can occur are
basically either:
1) ambiguous => no sensible measurement can be taken anyway
2) non-ambiguous is due to reordering => having the timestamp
of the last segment there is just skewing things more off
than does some good since the ack got triggered by one of
the holes (besides some substle issues that would make
determining right hole/skb even harder problem). Anyway,
it has nothing to do with this change then.
I choose to route some abnormal looking cases with goto noop,
some could be handled differently (eg., by stopping the
walking at that skb but again). In general, they either
shouldn't happen at all or are rare enough to make no difference
in practice.
In theory this change (as whole) could cause some macroscale
regression (global) because of cache misses that are taken over
the round-trip time but it gets very likely better because of much
less (local) cache misses per other write queue walkers and the
big recovery clearing cumulative ack.
Worth to note that these benefits would be very easy to get also
without TSO/GSO being on as long as the data is in pages so that
we can merge them. Currently I won't let that happen because
DSACK splitting at fragment that would mess up pcounts due to
sk_can_gso in tcp_set_skb_tso_segs. Once DSACKs fragments gets
avoided, we have some conditions that can be made less strict.
TODO: I will probably have to convert the excessive pointer
passing to struct sacktag_state... :-)
My testing revealed that considerable amount of skbs couldn't
be shifted because they were cloned (most likely still awaiting
tx reclaim)...
[The rest is considering future work instead since I got
repeatably EFAULT to tcpdump's recvfrom when I added
pskb_expand_head to deal with clones, so I separated that
into another, later patch]
...To counter that, I gave up on the fifth advantage:
5) When growing previous SACK block, less allocs for new skbs
are done, basically a new alloc is needed only when new hole
is detected and when the previous skb runs out of frags space
...which now only happens of if reclaim is fast enough to dispose
the clone before the SACK block comes in (the window is RTT long),
otherwise we'll have to alloc some.
With clones being handled I got these numbers (will be somewhat
worse without that), taken with fine-grained mibs:
TCPSackShifted 398
TCPSackMerged 877
TCPSackShiftFallback 320
TCPSACKCOLLAPSEFALLBACKGSO 0
TCPSACKCOLLAPSEFALLBACKSKBBITS 0
TCPSACKCOLLAPSEFALLBACKSKBDATA 0
TCPSACKCOLLAPSEFALLBACKBELOW 0
TCPSACKCOLLAPSEFALLBACKFIRST 1
TCPSACKCOLLAPSEFALLBACKPREVBITS 318
TCPSACKCOLLAPSEFALLBACKMSS 1
TCPSACKCOLLAPSEFALLBACKNOHEAD 0
TCPSACKCOLLAPSEFALLBACKSHIFT 0
TCPSACKCOLLAPSENOOPSEQ 0
TCPSACKCOLLAPSENOOPSMALLPCOUNT 0
TCPSACKCOLLAPSENOOPSMALLLEN 0
TCPSACKCOLLAPSEHOLE 12
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
Since skb_reset_tail_pointer() reads skb->data, we need to set
skb->data before calling skb_reset_tail_pointer(). This was causing
spurious skb_over_panic()s from skb_put() being called on a recycled
skb that had its skb->tail set to beyond where it should have been.
Bug report from Peter van Valderen <linux@ddcrew.com>.
Signed-off-by: Lennert Buytenhek <buytenh@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Commit 04a4bb55bc ("net: add
skb_recycle_check() to enable netdriver skb recycling") added a
method for network drivers to recycle skbuffs, but while use of
this mechanism was documented in the commit message, it should
really have been added as a docbook comment as well -- this
patch does that.
Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: Lennert Buytenhek <buytenh@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Wireless HW without any dedicated queues for aggregation
do not need the ampdu_queues mechanism present right now
in mac80211. Since mac80211 is still incomplete wrt TX MQ
changes, do not allow aggregation sessions for drivers that
set ampdu_queues.
This is only an interim hack until Intel fixes the requeue issue.
Signed-off-by: Sujith <Sujith.Manoharan@atheros.com>
Signed-off-by: Luis Rodriguez <Luis.Rodriguez@Atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Clean up the various different email addresses of mine listed in the code
to a single current and valid address. As Dave says his network merges
for 2.6.28 are now done this seems a good point to send them in where
they won't risk disrupting real changes.
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add some packet-split receive hooks.
For one this allows to do NUMA node affine page allocs. Later on these
hooks will be extended to do emergency reserve allocations for
fragments.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: David S. Miller <davem@davemloft.net>
If the caller of pskb_expand_head specifies a negative nhead
we'll silently overwrite other people's memory. This patch
makes it BUG instead.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch adds skb_recycle_check(), which can be used by a network
driver after transmitting an skb to check whether this skb can be
recycled as a receive buffer.
skb_recycle_check() checks that the skb is not shared or cloned, and
that it is linear and its head portion large enough (as determined by
the driver) to be recycled as a receive buffer. If these conditions
are met, it does any necessary reference count dropping and cleans
up the skbuff as if it just came from __alloc_skb().
Signed-off-by: Lennert Buytenhek <buytenh@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
skb_gso_segment didn't preserve some attributes in the original skb
such as the netfilter fields. This was harmless until they were used
which is the case for packets going through lo.
This patch makes it call __copy_skb_header which also picks up some
other missing attributes.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch fixes mac80211 to not use the skb->cb over the queue step
from virtual interfaces to the master. The patch also, for now,
disables aggregation because that would still require requeuing,
will fix that in a separate patch. There are two other places (software
requeue and powersaving stations) where requeue can happen, but that is
not currently used by any drivers/not possible to use respectively.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Removes legacy reinvent-the-wheel type thing. The generic
machinery integrates much better to automated debugging aids
such as kerneloops.org (and others), and is unambiguous due to
better naming. Non-intuively BUG_TRAP() is actually equal to
WARN_ON() rather than BUG_ON() though some might actually be
promoted to BUG_ON() but I left that to future.
I could make at least one BUILD_BUG_ON conversion.
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
net/core/skbuff.c:1335:5: warning: symbol '__skb_splice_bits' was not declared. Should it be static?
Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
- move all of the details on offsets, lengths and buffers into a
single function instead of doing these operation from multiple places
- use a bottom up approach: try to avoid details in the high level
functions, introduce them gradually as we go deeper in the function
call stack
With helpful feedback from Jarek Poplawski.
Signed-off-by: Octavian Purdila <opurdila@ixiacom.com>
Acked-by: Jarek Poplawski <jarkao2@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Use a real skb member to store the skb to avoid clashes with qdiscs,
which are allowed to use the cb area themselves. As currently only real
devices that consume the skb set the NETIF_F_HW_VLAN_TX flag, no explicit
invalidation is neccessary.
The new member fills a hole on 64 bit, the skb layout changes from:
__u32 mark; /* 172 4 */
sk_buff_data_t transport_header; /* 176 4 */
sk_buff_data_t network_header; /* 180 4 */
sk_buff_data_t mac_header; /* 184 4 */
sk_buff_data_t tail; /* 188 4 */
/* --- cacheline 3 boundary (192 bytes) --- */
sk_buff_data_t end; /* 192 4 */
/* XXX 4 bytes hole, try to pack */
to
__u32 mark; /* 172 4 */
__u16 vlan_tci; /* 176 2 */
/* XXX 2 bytes hole, try to pack */
sk_buff_data_t transport_header; /* 180 4 */
sk_buff_data_t network_header; /* 184 4 */
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
If an skb has nr_frags set to zero but its frag_list is not empty (as
it can happen if software LRO is enabled), and a previous
tcp_read_sock has consumed the linear part of the skb, then
__skb_splice_bits:
(a) incorrectly reports an error and
(b) forgets to update the offset to account for the linear part
Any of the two problems will cause the subsequent __skb_splice_bits
call (the one that handles the frag_list skbs) to either skip data,
or, if the unadjusted offset is greater then the size of the next skb
in the frag_list, make tcp_splice_read loop forever.
Signed-off-by: Octavian Purdila <opurdila@ixiacom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add skb_warn_if_lro() to test whether an skb was received with LRO and
warn if so.
Change br_forward(), ip_forward() and ip6_forward() to call it) and
discard the skb if it returns true.
Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch removes CVS keywords that weren't updated for a long time
from comments.
Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
skb_splice_bits temporary drops the socket lock while iterating over
the socket queue in order to break a reverse locking condition which
happens with sendfile. This, however, opens a window of opportunity
for tcp_collapse() to aggregate skbs and thus potentially free the
current skb used in skb_splice_bits and tcp_read_sock.
This patch fixes the problem by (re-)getting the same "logical skb"
after the lock has been temporary dropped.
Based on idea and initial patch from Evgeniy Polyakov.
Signed-off-by: Octavian Purdila <opurdila@ixiacom.com>
Acked-by: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Signed-off-by: David S. Miller <davem@davemloft.net>
include/linux/skbuff.h says:
/* These elements must be at the end, see alloc_skb() for details. */
net/core/skbuff.c says:
* See comment in sk_buff definition, just before the 'tail' member
This patch contains my guess as to the actual reason rather than a
dead comment reference loop.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
This expresses __skb_append in terms of __skb_queue_after, exploiting that
__skb_append(old, new, list) = __skb_queue_after(list, old, new).
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
The kernel-doc comment for skb_segment is clearly wrong. This states
what it actually does.
Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6: (82 commits)
[NET]: Make sure sockets implement splice_read
netconsole: avoid null pointer dereference at show_local_mac()
[IPV6]: Fix reversed local_df test in ip6_fragment
[XFRM]: Avoid bogus BUG() when throwing new policy away.
[AF_KEY]: Fix bug in spdadd
[NETFILTER] nf_conntrack_proto_tcp.c: Mistyped state corrected.
net: xfrm statistics depend on INET
[NETFILTER]: make secmark_tg_destroy() static
[INET]: Unexport inet_listen_wlock
[INET]: Unexport __inet_hash_connect
[NET]: Improve cache line coherency of ingress qdisc
[NET]: Fix race in dev_close(). (Bug 9750)
[IPSEC]: Fix bogus usage of u64 on input sequence number
[RTNETLINK]: Send a single notification on device state changes.
[NETLABLE]: Hide netlbl_unlabel_audit_addr6 under ifdef CONFIG_IPV6.
[NETLABEL]: Don't produce unused variables when IPv6 is off.
[NETLABEL]: Compilation for CONFIG_AUDIT=n case.
[GENETLINK]: Relax dances with genl_lock.
[NETLABEL]: Fix lookup logic of netlbl_domhsh_search_def.
[IPV6]: remove unused method declaration (net/ndisc.h).
...
Move networking (core and drivers) docbook to its own networking book.
Fix a few kernel-doc errors in header and source files.
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Cc: Neil Brown <neilb@suse.de>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Use it in virtio_net (replacing buggy version there), it's also going
to be used by TAP for partial csum support.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Acked-by: David S. Miller <davem@davemloft.net>
Both NetLabel and SELinux (other LSMs may grow to use it as well) rely
on the 'iif' field to determine the receiving network interface of
inbound packets. Unfortunately, at present this field is not
preserved across a skb clone operation which can lead to garbage
values if the cloned skb is sent back through the network stack. This
patch corrects this problem by properly copying the 'iif' field in
__skb_clone() and removing the 'iif' field assignment from
skb_act_clone() since it is no longer needed.
Also, while we are here, put the assignments in the same order as the
offsets to reduce cacheline bounces.
Signed-off-by: Paul Moore <paul.moore@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The skb_morph function only freed the data part of the dst skb, but leaked
the auxiliary data such as the netfilter fields. This patch fixes this by
moving the relevant parts from __kfree_skb to skb_release_all and calling
it in skb_morph.
It also makes kfree_skbmem static since it's no longer called anywhere else
and it now no longer does skb_release_data.
Thanks to Yasuyuki KOZAKAI for finding this problem and posting a patch for
it.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
sg_mark_end() overwrites the page_link information, but all users want
__sg_mark_end() behaviour where we just set the end bit. That is the most
natural way to use the sg list, since you'll fill it in and then mark the
end point.
So change sg_mark_end() to only set the termination bit. Add a sg_magic
debug check as well, and clear a chain pointer if it is set.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
This fixes scatterlist corruptions added by
commit 68e3f5dd4d
[CRYPTO] users: Fix up scatterlist conversion errors
The issue is that the code calls sg_mark_end() which clobbers the
sg_page() pointer of the final scatterlist entry.
The first part fo the fix makes skb_to_sgvec() do __sg_mark_end().
After considering all skb_to_sgvec() call sites the most correct
solution is to call __sg_mark_end() in skb_to_sgvec() since that is
what all of the callers would end up doing anyways.
I suspect this might have fixed some problems in virtio_net which is
the sole non-crypto user of skb_to_sgvec().
Other similar sg_mark_end() cases were converted over to
__sg_mark_end() as well.
Arguably sg_mark_end() is a poorly named function because it doesn't
just "mark", it clears out the page pointer as a side effect, which is
what led to these bugs in the first place.
The one remaining plain sg_mark_end() call is in scsi_alloc_sgtable()
and arguably it could be converted to __sg_mark_end() if only so that
we can delete this confusing interface from linux/scatterlist.h
Signed-off-by: David S. Miller <davem@davemloft.net>
clean skb_clone of any signs of CONFIG_NET_CLS_ACT and
have mirred us skb_act_clone()
Signed-off-by: Jamal Hadi Salim <hadi@cyberus.ca>
Signed-off-by: David S. Miller <davem@davemloft.net>
Most drivers need to set length and offset as well, so may as well fold
those three lines into one.
Add sg_assign_page() for those two locations that only needed to set
the page, where the offset/length is set outside of the function context.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
I got confused by the dual nature of the off variable in the
function pskb_expand_head. The csum_start offset should use
nhead instead of off which can change depending on whether we
are using offsets or pointers.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch creates a new function skb_morph that's just like skb_clone
except that it lets user provide the spare skb that will be overwritten
by the one that's to be cloned.
This will be used by IP fragment reassembly so that we get back the same
skb that went in last (rather than the head skb that we get now which
requires us to carry around double pointers all over the place).
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch creates a new function __copy_skb_header to merge the common
code between copy_skb_header and skb_clone. Having two functions which
are largely the same is a source of wasted labour as well as confusion.
In fact the tc_verd stuff is almost certainly a bug since it's treated
differently in skb_clone compared to the callers of copy_skb_header
(skb_copy/pskb_copy/skb_copy_expand).
I've kept that difference in tact with a comment added asking for
clarification.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
Thanks for noticing the bug where csum_start is not updated
when the head room changes.
This patch fixes that. It also moves the csum/ip_summed
copying into copy_skb_header so that skb_copy_expand gets
it too. I've checked its callers and no one should be upset
by this.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
Slab destructors were no longer supported after Christoph's
c59def9f22 change. They've been
BUGs for both slab and slub, and slob never supported them
either.
This rips out support for the dtor pointer from kmem_cache_create()
completely and fixes up every single callsite in the kernel (there were
about 224, not including the slab allocator definitions themselves,
or the documentation references).
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
The TRACE target can be used to follow IP and IPv6 packets through
the ruleset.
Signed-off-by: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
Signed-off-by: Patrick NcHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
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 <peter.p.waskiewicz.jr@intel.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
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 <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
skb_clone_fraglist is static so it shouldn't be exported.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Having walked through the entire skbuff, skb_seq_read would leave the
last fragment mapped. As a consequence, the unwary caller would leak
kmaps, and proceed with preempt_count off by one. The only (kind of
non-intuitive) workaround is to use skb_seq_read_abort.
This patch makes sure skb_seq_read always unmaps frag_data after
having cycled through the skb's paged part.
Signed-off-by: Olaf Kirch <olaf.kirch@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
secmark doesn't depend on CONFIG_NET_SCHED.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Compiling 2.6.22-rc1 with gcc-3.2.3 for i486 fails with:
gcc -m32 -Wp,-MD,net/core/.skbuff.o.d -nostdinc -isystem /home/mikpe/pkgs/linux-x86/gnu/lib/gcc-lib/i486-pc-linux-gnu/3.2.3/include -D__KERNEL__ -Iinclude -include include/linux/autoconf.h -Wall -Wundef -Wstrict-prototypes -Wno-trigraphs -fno-strict-aliasing -fno-common -O2 -pipe -msoft-float -mregparm=3 -freg-struct-return -mpreferred-stack-boundary=4 -march=i486 -ffreestanding -maccumulate-outgoing-args -DCONFIG_AS_CFI=1 -Iinclude/asm-i386/mach-default -fomit-frame-pointer -D"KBUILD_STR(s)=#s" -D"KBUILD_BASENAME=KBUILD_STR(skbuff)" -D"KBUILD_MODNAME=KBUILD_STR(skbuff)" -c -o net/core/skbuff.o net/core/skbuff.c
net/core/skbuff.c:648:1: directives may not be used inside a macro argument
net/core/skbuff.c:647:39: unterminated argument list invoking macro "memcpy"
net/core/skbuff.c: In function `pskb_expand_head':
net/core/skbuff.c:651: `memcpy' undeclared (first use in this function)
net/core/skbuff.c:651: (Each undeclared identifier is reported only once
net/core/skbuff.c:651: for each function it appears in.)
net/core/skbuff.c:651: syntax error before "skb"
make[2]: *** [net/core/skbuff.o] Error 1
make[1]: *** [net/core] Error 2
make: *** [net] Error 2
The patch below implements a simple workaround which is to
clone the offending memcpy() call and specialise it for the
two different scenarios.
Other workarounds are of course possible: e.g. bind the varying
parameter in a local variable, or use a macro or inline function
to perform the varying computation.
Signed-off-by: Mikael Pettersson <mikpe@it.uu.se>
Signed-off-by: David S. Miller <davem@davemloft.net>
This reverts eefa390628
The simplification made in that change works with the assumption that
the 'offset' parameter to these functions is always positive or zero,
which is not true. It can be and often is negative in order to access
SKB header values in front of skb->data.
Signed-off-by: David S. Miller <davem@davemloft.net>
I noticed recently that, in skb_checksum(), "offset" and "start" are
essentially the same thing and have the same value throughout the
function, despite being computed differently. Using a single variable
allows some cleanups and makes the skb_checksum() function smaller,
more readable, and presumably marginally faster.
We appear to have many other "sk_buff walker" functions built on the
exact same model, so the cleanup applies to them, too. Here is a list
of the functions I found to be affected:
net/appletalk/ddp.c:atalk_sum_skb()
net/core/datagram.c:skb_copy_datagram_iovec()
net/core/datagram.c:skb_copy_and_csum_datagram()
net/core/skbuff.c:skb_copy_bits()
net/core/skbuff.c:skb_store_bits()
net/core/skbuff.c:skb_checksum()
net/core/skbuff.c:skb_copy_and_csum_bit()
net/core/user_dma.c:dma_skb_copy_datagram_iovec()
net/xfrm/xfrm_algo.c:skb_icv_walk()
net/xfrm/xfrm_algo.c:skb_to_sgvec()
OTOH, I admit I'm a bit surprised, the cleanup is rather obvious so I'm
really wondering if I am missing something. Can anyone please comment
on this?
Signed-off-by: Jean Delvare <jdelvare@suse.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
Spring cleaning time...
There seems to be a lot of places in the network code that have
extra bogus semicolons after conditionals. Most commonly is a
bogus semicolon after: switch() { }
Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Getting warnings becuase skb_store_bits has skb as constant,
but the function overwrites it. Looks like const was on the
wrong side.
Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
skb_copy_expand changes the headroom, so it needs to adjust the header
offsets by the difference between the old and the new value.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
The skb transport pointer is currently used to specify the start
of the checksum region for transmit checksum offload. Unfortunately,
the same pointer is also used during receive side processing.
This creates a problem when we want to retransmit a received
packet with partial checksums since the skb transport pointer
would be overwritten.
This patch solves this problem by creating a new 16-bit csum_start
offset value to replace the skb transport header for the purpose
of checksums. This offset is calculated from skb->head so that
it does not have to change when skb->data changes.
No extra space is required since csum_offset itself fits within
a 16-bit word so we can use the other 16 bits for csum_start.
For backwards compatibility, just before we push a packet with
partial checksums off into the device driver, we set the skb
transport header to what it would have been under the old scheme.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
Since we're increasing the headroom, the header offsets need to be
increased by the same amount as well.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Move generic skbuff stuff from XFRM code to generic code so that
AF_RXRPC can use it too.
The kdoc comments I've attached to the functions needs to be checked
by whoever wrote them as I had to make some guesses about the workings
of these functions.
Signed-off-By: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
To clearly state the intent of copying to linear sk_buffs, _offset being a
overly long variant but interesting for the sake of saving some bytes.
Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
To clearly state the intent of copying from linear sk_buffs, _offset being a
overly long variant but interesting for the sake of saving some bytes.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Yasuyuki Kozakai <yasuyuki.kozakai@toshiba.co.jp>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
I did it just in alloc_skb_from_cache, forgot __alloc_skb, fixed now.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Now to convert the last one, skb->data, that will allow many simplifications
and removal of some of the offset helpers.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
So that it is also an offset from skb->head, reduces its size from 8 to 4 bytes
on 64bit architectures, allowing us to combine the 4 bytes hole left by the
layer headers conversion, reducing struct sk_buff size to 256 bytes, i.e. 4
64byte cachelines, and since the sk_buff slab cache is SLAB_HWCACHE_ALIGN...
:-)
Many calculations that previously required that skb->{transport,network,
mac}_header be first converted to a pointer now can be done directly, being
meaningful as offsets or pointers.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Renaming skb->h to skb->transport_header, skb->nh to skb->network_header and
skb->mac to skb->mac_header, to match the names of the associated helpers
(skb[_[re]set]_{transport,network,mac}_header).
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
For the common sequence "skb->h.raw - skb->nh.raw", similar to skb->mac_len,
that is precalculated tho, don't think we need to bloat skb with one more
member, so just use this new helper, reducing the number of non-skbuff.h
references to the layer headers even more.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This unifies the codes to copy netfilter related datas. Note that
__nf_copy() assumes destination skb doesn't have any netfilter
related members.
Signed-off-by: Yasuyuki Kozakai <yasuyuki.kozakai@toshiba.co.jp>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
For the quite common 'skb->h.raw - skb->data' sequence.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
David S. Miller