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>
