Netlink families can exist in multiple namespaces, and for the most
part multicast subscriptions are per network namespace. Thus it only
makes sense to have bind/unbind notifications per network namespace.
To achieve this, pass the network namespace of a given client socket
to the bind/unbind functions.
Also do this in generic netlink, and there also make sure that any
bind for multicast groups that only exist in init_net is rejected.
This isn't really a problem if it is accepted since a client in a
different namespace will never receive any notifications from such
a group, but it can confuse the family if not rejected (it's also
possible to silently (without telling the family) accept it, but it
would also have to be ignored on unbind so families that take any
kind of action on bind/unbind won't do unnecessary work for invalid
clients like that.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Conflicts:
include/net/inetpeer.h
net/ipv6/output_core.c
Changes in net were fixing bugs in code removed in net-next.
Signed-off-by: David S. Miller <davem@davemloft.net>
It was possible to get a setuid root or setcap executable to write to
it's stdout or stderr (which has been set made a netlink socket) and
inadvertently reconfigure the networking stack.
To prevent this we check that both the creator of the socket and
the currentl applications has permission to reconfigure the network
stack.
Unfortunately this breaks Zebra which always uses sendto/sendmsg
and creates it's socket without any privileges.
To keep Zebra working don't bother checking if the creator of the
socket has privilege when a destination address is specified. Instead
rely exclusively on the privileges of the sender of the socket.
Note from Andy: This is exactly Eric's code except for some comment
clarifications and formatting fixes. Neither I nor, I think, anyone
else is thrilled with this approach, but I'm hesitant to wait on a
better fix since 3.15 is almost here.
Note to stable maintainers: This is a mess. An earlier series of
patches in 3.15 fix a rather serious security issue (CVE-2014-0181),
but they did so in a way that breaks Zebra. The offending series
includes:
commit aa4cf9452f
Author: Eric W. Biederman <ebiederm@xmission.com>
Date: Wed Apr 23 14:28:03 2014 -0700
net: Add variants of capable for use on netlink messages
If a given kernel version is missing that series of fixes, it's
probably worth backporting it and this patch. if that series is
present, then this fix is critical if you care about Zebra.
Cc: stable@vger.kernel.org
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Conflicts:
drivers/net/ethernet/altera/altera_sgdma.c
net/netlink/af_netlink.c
net/sched/cls_api.c
net/sched/sch_api.c
The netlink conflict dealt with moving to netlink_capable() and
netlink_ns_capable() in the 'net' tree vs. supporting 'tc' operations
in non-init namespaces. These were simple transformations from
netlink_capable to netlink_ns_capable.
The Altera driver conflict was simply code removal overlapping some
void pointer cast cleanups in net-next.
Signed-off-by: David S. Miller <davem@davemloft.net>
netlink_net_capable - The common case use, for operations that are safe on a network namespace
netlink_capable - For operations that are only known to be safe for the global root
netlink_ns_capable - The general case of capable used to handle special cases
__netlink_ns_capable - Same as netlink_ns_capable except taking a netlink_skb_parms instead of
the skbuff of a netlink message.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Have the netlink per-protocol optional bind function return an int error code
rather than void to signal a failure.
This will enable netlink protocols to perform extra checks including
capabilities and permissions verifications when updating memberships in
multicast groups.
In netlink_bind() and netlink_setsockopt() the call to the per-protocol bind
function was moved above the multicast group update to prevent any access to
the multicast socket groups before checking with the per-protocol bind
function. This will enable the per-protocol bind function to be used to check
permissions which could be denied before making them available, and to avoid
the messy job of undoing the addition should the per-protocol bind function
fail.
The netfilter subsystem seems to be the only one currently using the
per-protocol bind function.
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Cleanups in netlink_tap code
* remove unused function netlink_clear_multicast_users
* make local function static
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Reviewed-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Since (c05cdb1 netlink: allow large data transfers from user-space),
netlink splats if it invokes skb_clone on large netlink skbs since:
* skb_shared_info was not correctly initialized.
* skb->destructor is not set in the cloned skb.
This was spotted by trinity:
[ 894.990671] BUG: unable to handle kernel paging request at ffffc9000047b001
[ 894.991034] IP: [<ffffffff81a212c4>] skb_clone+0x24/0xc0
[...]
[ 894.991034] Call Trace:
[ 894.991034] [<ffffffff81ad299a>] nl_fib_input+0x6a/0x240
[ 894.991034] [<ffffffff81c3b7e6>] ? _raw_read_unlock+0x26/0x40
[ 894.991034] [<ffffffff81a5f189>] netlink_unicast+0x169/0x1e0
[ 894.991034] [<ffffffff81a601e1>] netlink_sendmsg+0x251/0x3d0
Fix it by:
1) introducing a new netlink_skb_clone function that is used in nl_fib_input,
that sets our special skb->destructor in the cloned skb. Moreover, handle
the release of the large cloned skb head area in the destructor path.
2) not allowing large skbuffs in the netlink broadcast path. I cannot find
any reasonable use of the large data transfer using netlink in that path,
moreover this helps to skip extra skb_clone handling.
I found two more netlink clients that are cloning the skbs, but they are
not in the sendmsg path. Therefore, the sole client cloning that I found
seems to be the fib frontend.
Thanks to Eric Dumazet for helping to address this issue.
Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Similarly to the networking receive path with ptype_all taps, we add
the possibility to register netdevices that are for ARPHRD_NETLINK to
the netlink subsystem, so that those can be used for netlink analyzers
resp. debuggers. We do not offer a direct callback function as out-of-tree
modules could do crap with it. Instead, a netdevice must be registered
properly and only receives a clone, managed by the netlink layer. Symbols
are exported as GPL-only.
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
As we know, netlink sockets are private resource of
net namespace, they can communicate with each other
only when they in the same net namespace. this works
well until we try to add namespace support for other
subsystems which use netlink.
Don't like ipv4 and route table.., it is not suited to
make these subsytems belong to net namespace, Such as
audit and crypto subsystems,they are more suitable to
user namespace.
So we must have the ability to make the netlink sockets
in same user namespace can communicate with each other.
This patch adds a new function pointer "compare" for
netlink_table, we can decide if the netlink sockets can
communicate with each other through this netlink_table
self-defined compare function.
The behavior isn't changed if we don't provide the compare
function for netlink_table.
Signed-off-by: Gao feng <gaofeng@cn.fujitsu.com>
Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add support for mmap'ed recvmsg(). To allow the kernel to construct messages
into the mapped area, a dataless skb is allocated and the data pointer is
set to point into the ring frame. This means frames will be delivered to
userspace in order of allocation instead of order of transmission. This
usually doesn't matter since the order is either not determinable by
userspace or message creation/transmission is serialized. The only case
where this can have a visible difference is nfnetlink_queue. Userspace
can't assume mmap'ed messages have ordered IDs anymore and needs to check
this if using batched verdicts.
For non-mapped sockets, nothing changes.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add helper functions for looking up mmap'ed frame headers, reading and
writing their status, allocating skbs with mmap'ed data areas and a poll
function.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Memory mapped netlink needs to store the receiving userspace socket
when sending from the kernel to userspace. Rename 'ssk' to 'sk' to
avoid confusion.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Michael Kerrisk <mtk.manpages@gmail.com>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Dave Jones <davej@redhat.com>
I get a panic when I use ss -a and rmmod inet_diag at the
same time.
It's because netlink_dump uses inet_diag_dump which belongs to module
inet_diag.
I search the codes and find many modules have the same problem. We
need to add a reference to the module which the cb->dump belongs to.
Thanks for all help from Stephen,Jan,Eric,Steffen and Pablo.
Change From v3:
change netlink_dump_start to inline,suggestion from Pablo and
Eric.
Change From v2:
delete netlink_dump_done,and call module_put in netlink_dump
and netlink_sock_destruct.
Signed-off-by: Gao feng <gaofeng@cn.fujitsu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Since (9f00d97 netlink: hide struct module parameter in netlink_kernel_create),
linux/netlink.h includes linux/module.h because of the use of THIS_MODULE.
Use linux/export.h instead, as suggested by Stephen Rothwell, which is
significantly smaller and defines THIS_MODULES.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
It is a frequent mistake to confuse the netlink port identifier with a
process identifier. Try to reduce this confusion by renaming fields
that hold port identifiers portid instead of pid.
I have carefully avoided changing the structures exported to
userspace to avoid changing the userspace API.
I have successfully built an allyesconfig kernel with this change.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch defines netlink_kernel_create as a wrapper function of
__netlink_kernel_create to hide the struct module *me parameter
(which seems to be THIS_MODULE in all existing netlink subsystems).
Suggested by David S. Miller.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Replace netlink_set_nonroot by one new field `flags' in
struct netlink_kernel_cfg that is passed to netlink_kernel_create.
This patch also renames NL_NONROOT_* to NL_CFG_F_NONROOT_* since
now the flags field in nl_table is generic (so we can add more
flags if needed in the future).
Also adjust all callers in the net-next tree to use these flags
instead of netlink_set_nonroot.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Passing uids and gids on NETLINK_CB from a process in one user
namespace to a process in another user namespace can result in the
wrong uid or gid being presented to userspace. Avoid that problem by
passing kuids and kgids instead.
- define struct scm_creds for use in scm_cookie and netlink_skb_parms
that holds uid and gid information in kuid_t and kgid_t.
- Modify scm_set_cred to fill out scm_creds by heand instead of using
cred_to_ucred to fill out struct ucred. This conversion ensures
userspace does not get incorrect uid or gid values to look at.
- Modify scm_recv to convert from struct scm_creds to struct ucred
before copying credential values to userspace.
- Modify __scm_send to populate struct scm_creds on in the scm_cookie,
instead of just copying struct ucred from userspace.
- Modify netlink_sendmsg to copy scm_creds instead of struct ucred
into the NETLINK_CB.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The sending socket of an skb is already available by it's port id
in the NETLINK_CB. If you want to know more like to examine the
credentials on the sending socket you have to look up the sending
socket by it's port id and all of the needed functions and data
structures are static inside of af_netlink.c. So do the simple
thing and pass the sending socket to the receivers in the NETLINK_CB.
I intend to use this to get the user namespace of the sending socket
in inet_diag so that I can report uids in the context of the process
who opened the socket, the same way I report uids in the contect
of the process who opens files.
Acked-by: David S. Miller <davem@davemloft.net>
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
This patch adds a hook in the binding path of netlink.
This is used by ctnetlink to allow module autoloading for the case
in which one user executes:
conntrack -E
So far, this resulted in nfnetlink loaded, but not
nf_conntrack_netlink.
I have received in the past many complains on this behaviour.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch adds the following structure:
struct netlink_kernel_cfg {
unsigned int groups;
void (*input)(struct sk_buff *skb);
struct mutex *cb_mutex;
};
That can be passed to netlink_kernel_create to set optional configurations
for netlink kernel sockets.
I've populated this structure by looking for NULL and zero parameters at the
existing code. The remaining parameters that always need to be set are still
left in the original interface.
That includes optional parameters for the netlink socket creation. This allows
easy extensibility of this interface in the future.
This patch also adapts all callers to use this new interface.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch removes ip_queue support which was marked as obsolete
years ago. The nfnetlink_queue modules provides more advanced
user-space packet queueing mechanism.
This patch also removes capability code included in SELinux that
refers to ip_queue. Otherwise, we break compilation.
Several warning has been sent regarding this to the mailing list
in the past month without anyone rising the hand to stop this
with some strong argument.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This patch allows you to pass a data pointer that can be
accessed from the dump callback.
Netfilter is going to use this patch to provide filtered dumps
to user-space. This is specifically interesting in ctnetlink that
may handle lots of conntrack entries. We can save precious
cycles by skipping the conversion to TLV format of conntrack
entries that are not interesting for user-space.
More specifically, ctnetlink will include one operation to allow
to filter the dumping of conntrack entries by ctmark values.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Davem considers that the argument list of this interface is getting
out of control. This patch tries to address this issue following
his proposal:
struct netlink_dump_control c = { .dump = dump, .done = done, ... };
netlink_dump_start(..., &c);
Suggested by David S. Miller.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
text data bss dec hex filename
8455963 532732 1810804 10799499 a4c98b vmlinux.o.before
8448899 532732 1810804 10792435 a4adf3 vmlinux.o
This change also removes commented-out copy of __nlmsg_put
which was last touched in 2005 with "Enable once all users
have been converted" comment on top.
Changes in v2: rediffed against net-next.
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The ultimate goal is to get the sock_diag module, that works in
family+protocol terms. Currently this is suitable to do on the
inet_diag basis, so rename parts of the code. It will be moved
to sock_diag.c later.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
* git://github.com/herbertx/crypto: (48 commits)
crypto: user - Depend on NET instead of selecting it
crypto: user - Add dependency on NET
crypto: talitos - handle descriptor not found in error path
crypto: user - Initialise match in crypto_alg_match
crypto: testmgr - add twofish tests
crypto: testmgr - add blowfish test-vectors
crypto: Make hifn_795x build depend on !ARCH_DMA_ADDR_T_64BIT
crypto: twofish-x86_64-3way - fix ctr blocksize to 1
crypto: blowfish-x86_64 - fix ctr blocksize to 1
crypto: whirlpool - count rounds from 0
crypto: Add userspace report for compress type algorithms
crypto: Add userspace report for cipher type algorithms
crypto: Add userspace report for rng type algorithms
crypto: Add userspace report for pcompress type algorithms
crypto: Add userspace report for nivaead type algorithms
crypto: Add userspace report for aead type algorithms
crypto: Add userspace report for givcipher type algorithms
crypto: Add userspace report for ablkcipher type algorithms
crypto: Add userspace report for blkcipher type algorithms
crypto: Add userspace report for ahash type algorithms
...
This patch adds a basic userspace configuration API for the crypto layer.
With this it is possible to instantiate, remove and to show crypto
algorithms from userspace.
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Complete the work started with commit
6602a4baf4 ('net: Make userland include
of netlink.h more sane').
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
Currently userland will barf when including linux/netlink.h unless it
precisely includes sys/socket.h first. The issue is where the
definition of "sa_family_t" comes from.
We've been back and forth on how to fix this issue in the past, see:
http://thread.gmane.org/gmane.linux.debian.devel.bugs.general/622621http://thread.gmane.org/gmane.linux.network/143380
Ben Hutchings suggested we take a hint from how we handle the
sockaddr_storage type. First we define a "__kernel_sa_family_t"
to linux/socket.h that is always defined.
Then if __KERNEL__ is defined, we also define "sa_family_t" as
equal to "__kernel_sa_family_t".
Then in places like linux/netlink.h we use __kernel_sa_family_t
in user visible datastructures.
Reported-by: Michel Machado <michel@digirati.com.br>
Signed-off-by: David S. Miller <davem@davemloft.net>
Consider the following situation:
* a dump that would show 8 entries, four in the first
round, and four in the second
* between the first and second rounds, 6 entries are
removed
* now the second round will not show any entry, and
even if there is a sequence/generation counter the
application will not know
To solve this problem, add a new flag NLM_F_DUMP_INTR
to the netlink header that indicates the dump wasn't
consistent, this flag can also be set on the MSG_DONE
message that terminates the dump, and as such above
situation can be detected.
To achieve this, add a sequence counter to the netlink
callback struct. Of course, netlink code still needs
to use this new functionality. The correct way to do
that is to always set cb->seq when a dumpit callback
is invoked and call nl_dump_check_consistent() for
each new message. The core code will also call this
function for the final MSG_DONE message.
To make it usable with generic netlink, a new function
genlmsg_nlhdr() is needed to obtain the netlink header
from the genetlink user header.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
The message size allocated for rtnl ifinfo dumps was limited to
a single page. This is not enough for additional interface info
available with devices that support SR-IOV and caused a bug in
which VF info would not be displayed if more than approximately
40 VFs were created per interface.
Implement a new function pointer for the rtnl_register service that will
calculate the amount of data required for the ifinfo dump and allocate
enough data to satisfy the request.
Signed-off-by: Greg Rose <gregory.v.rose@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Add basic RDMA netlink infrastructure that allows for registration of
RDMA clients for which data is to be exported and supplies message
construction callbacks.
Signed-off-by: Nir Muchtar <nirm@voltaire.com>
[ Reorganize a few things, add CONFIG_NET dependency. - Roland ]
Signed-off-by: Roland Dreier <roland@purestorage.com>
Netlink message processing in the kernel is synchronous these days,
capabilities can be checked directly in security_netlink_recv() from
the current process.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Reviewed-by: James Morris <jmorris@namei.org>
[chrisw: update to include pohmelfs and uvesafb]
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Netlink message processing in the kernel is synchronous these days, the
session information can be collected when needed.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
$ cat << EOF | gcc -Wconversion -xc -S -o/dev/null -
unsigned f(void) {return NLMSG_HDRLEN;}
EOF
<stdin>: In function 'f':
<stdin>:3:26: warning: negative integer implicitly converted to unsigned type
Signed-off-by: Dmitry V. Levin <ldv@altlinux.org>
Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch reduces namespace pollution by moving the "struct net" declaration
out of the userspace-facing portion of linux/netlink.h. It has no impact on
the kernel.
(This came up because we have several C++ applications which use "net" as a
namespace name.)
Signed-off-by: Ollie Wild <aaw@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
When netlink sockets are used to convey data that is in a namespace
we need a way to select a subset of the listening sockets to deliver
the packet to. For the network namespace we have been doing this
by only transmitting packets in the correct network namespace.
For data belonging to other namespaces netlink_bradcast_filtered
provides a mechanism that allows us to examine the destination
socket and to decide if we should transmit the specified packet
to it.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Currently, ENOBUFS errors are reported to the socket via
netlink_set_err() even if NETLINK_RECV_NO_ENOBUFS is set. However,
that should not happen. This fixes this problem and it changes the
prototype of netlink_set_err() to return the number of sockets that
have set the NETLINK_RECV_NO_ENOBUFS socket option. This return
value is used in the next patch in these bugfix series.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This cleanup patch puts struct/union/enum opening braces,
in first line to ease grep games.
struct something
{
becomes :
struct something {
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Similar to commit d136f1bd36,
there's a bug when unregistering a generic netlink family,
which is caught by the might_sleep() added in that commit:
BUG: sleeping function called from invalid context at net/netlink/af_netlink.c:183
in_atomic(): 1, irqs_disabled(): 0, pid: 1510, name: rmmod
2 locks held by rmmod/1510:
#0: (genl_mutex){+.+.+.}, at: [<ffffffff8138283b>] genl_unregister_family+0x2b/0x130
#1: (rcu_read_lock){.+.+..}, at: [<ffffffff8138270c>] __genl_unregister_mc_group+0x1c/0x120
Pid: 1510, comm: rmmod Not tainted 2.6.31-wl #444
Call Trace:
[<ffffffff81044ff9>] __might_sleep+0x119/0x150
[<ffffffff81380501>] netlink_table_grab+0x21/0x100
[<ffffffff813813a3>] netlink_clear_multicast_users+0x23/0x60
[<ffffffff81382761>] __genl_unregister_mc_group+0x71/0x120
[<ffffffff81382866>] genl_unregister_family+0x56/0x130
[<ffffffffa0007d85>] nl80211_exit+0x15/0x20 [cfg80211]
[<ffffffffa000005a>] cfg80211_exit+0x1a/0x40 [cfg80211]
Fix in the same way by grabbing the netlink table lock
before doing rcu_read_lock().
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Since my commits introducing netns awareness into
genetlink we can get this problem:
BUG: scheduling while atomic: modprobe/1178/0x00000002
2 locks held by modprobe/1178:
#0: (genl_mutex){+.+.+.}, at: [<ffffffff8135ee1a>] genl_register_mc_grou
#1: (rcu_read_lock){.+.+..}, at: [<ffffffff8135eeb5>] genl_register_mc_g
Pid: 1178, comm: modprobe Not tainted 2.6.31-rc8-wl-34789-g95cb731-dirty #
Call Trace:
[<ffffffff8103e285>] __schedule_bug+0x85/0x90
[<ffffffff81403138>] schedule+0x108/0x588
[<ffffffff8135b131>] netlink_table_grab+0xa1/0xf0
[<ffffffff8135c3a7>] netlink_change_ngroups+0x47/0x100
[<ffffffff8135ef0f>] genl_register_mc_group+0x12f/0x290
because I overlooked that netlink_table_grab() will
schedule, thinking it was just the rwlock. However,
in the contention case, that isn't actually true.
Fix this by letting the code grab the netlink table
lock first and then the RCU for netns protection.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Consitfy nlmsghdr arguments to a couple of functions as preparation
for the next patch, which will constify the netlink message data in
all nfnetlink users.
Signed-off-by: Patrick McHardy <kaber@trash.net>
This patch adds the NETLINK_NO_ENOBUFS socket flag. This flag can
be used by unicast and broadcast listeners to avoid receiving
ENOBUFS errors.
Generally speaking, ENOBUFS errors are useful to notify two things
to the listener:
a) You may increase the receiver buffer size via setsockopt().
b) You have lost messages, you may be out of sync.
In some cases, ignoring ENOBUFS errors can be useful. For example:
a) nfnetlink_queue: this subsystem does not have any sort of resync
method and you can decide to ignore ENOBUFS once you have set a
given buffer size.
b) ctnetlink: you can use this together with the socket flag
NETLINK_BROADCAST_SEND_ERROR to stop getting ENOBUFS errors as
you do not need to resync (packets whose event are not delivered
are drop to provide reliable logging and state-synchronization).
Moreover, the use of NETLINK_NO_ENOBUFS also reduces a "go up, go down"
effect in terms of performance which is due to the netlink congestion
control when the listener cannot back off. The effect is the following:
1) throughput rate goes up and netlink messages are inserted in the
receiver buffer.
2) Then, netlink buffer fills and overruns (set on nlk->state bit 0).
3) While the listener empties the receiver buffer, netlink keeps
dropping messages. Thus, throughput goes dramatically down.
4) Then, once the listener has emptied the buffer (nlk->state
bit 0 is set off), goto step 1.
This effect is easy to trigger with netlink broadcast under heavy
load, and it is more noticeable when using a big receiver buffer.
You can find some results in [1] that show this problem.
[1] http://1984.lsi.us.es/linux/netlink/
This patch also includes the use of sk_drop to account the number of
netlink messages drop due to overrun. This value is shown in
/proc/net/netlink.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch adds NETLINK_BROADCAST_ERROR which is a netlink
socket option that the listener can set to make netlink_broadcast()
return errors in the delivery to the caller. This option is useful
if the caller of netlink_broadcast() do something with the result
of the message delivery, like in ctnetlink where it drops a network
packet if the event delivery failed, this is used to enable reliable
logging and state-synchronization. If this socket option is not set,
netlink_broadcast() only reports ESRCH errors and silently ignore
ENOBUFS errors, which is what most netlink_broadcast() callers
should do.
This socket option is based on a suggestion from Patrick McHardy.
Patrick McHardy can exchange this patch for a beer from me ;).
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Acked-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Johannes Berg