The goal is to let the user follow an interface that moves to another
netns.

CC: Jiri Benc <jbenc@redhat.com>
CC: Christian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: NNicolas Dichtel <nicolas.dichtel@6wind.com>
Reviewed-by: NJiri Benc <jbenc@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

- Backwards Compatibility:
  If userspace wants to determine whether RTM_DELLINK supports the
  IFLA_IF_NETNSID property they should first send an RTM_GETLINK request
  with IFLA_IF_NETNSID on lo. If either EACCESS is returned or the reply
  does not include IFLA_IF_NETNSID userspace should assume that
  IFLA_IF_NETNSID is not supported on this kernel.
  If the reply does contain an IFLA_IF_NETNSID property userspace
  can send an RTM_DELLINK with a IFLA_IF_NETNSID property. If they receive
  EOPNOTSUPP then the kernel does not support the IFLA_IF_NETNSID property
  with RTM_DELLINK. Userpace should then fallback to other means.

- Security:
  Callers must have CAP_NET_ADMIN in the owning user namespace of the
  target network namespace.
Signed-off-by: NChristian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

- Backwards Compatibility:
  If userspace wants to determine whether RTM_SETLINK supports the
  IFLA_IF_NETNSID property they should first send an RTM_GETLINK request
  with IFLA_IF_NETNSID on lo. If either EACCESS is returned or the reply
  does not include IFLA_IF_NETNSID userspace should assume that
  IFLA_IF_NETNSID is not supported on this kernel.
  If the reply does contain an IFLA_IF_NETNSID property userspace
  can send an RTM_SETLINK with a IFLA_IF_NETNSID property. If they receive
  EOPNOTSUPP then the kernel does not support the IFLA_IF_NETNSID property
  with RTM_SETLINK. Userpace should then fallback to other means.

  To retain backwards compatibility the kernel will first check whether a
  IFLA_NET_NS_PID or IFLA_NET_NS_FD property has been passed. If either
  one is found it will be used to identify the target network namespace.
  This implies that users who do not care whether their running kernel
  supports IFLA_IF_NETNSID with RTM_SETLINK can pass both
  IFLA_NET_NS_{FD,PID} and IFLA_IF_NETNSID referring to the same network
  namespace.

- Security:
  Callers must have CAP_NET_ADMIN in the owning user namespace of the
  target network namespace.
Signed-off-by: NChristian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

RTM_{NEW,SET}LINK already allow operations on other network namespaces
by identifying the target network namespace through IFLA_NET_NS_{FD,PID}
properties. This is done by looking for the corresponding properties in
do_setlink(). Extend do_setlink() to also look for the IFLA_IF_NETNSID
property. This introduces no functional changes since all callers of
do_setlink() currently block IFLA_IF_NETNSID by reporting an error before
they reach do_setlink().

This introduces the helpers:

static struct net *rtnl_link_get_net_by_nlattr(struct net *src_net, struct
                                               nlattr *tb[])

static struct net *rtnl_link_get_net_capable(const struct sk_buff *skb,
                                             struct net *src_net,
					     struct nlattr *tb[], int cap)

to simplify permission checks and target network namespace retrieval for
RTM_* requests that already support IFLA_NET_NS_{FD,PID} but get extended
to IFLA_IF_NETNSID. To perserve backwards compatibility the helpers look
for IFLA_NET_NS_{FD,PID} properties first before checking for
IFLA_IF_NETNSID.
Signed-off-by: NChristian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Expose the number of times the link has been going UP or DOWN, and
update the "carrier_changes" counter to be the sum of these two events.
While at it, also update the sysfs-class-net documentation to cover:
carrier_changes (3.15), carrier_up_count (4.16) and carrier_down_count
(4.16)
Signed-off-by: NDavid Decotigny <decot@googlers.com>
[Florian:
* rebase
* add documentation
* merge carrier_changes with up/down counters]
Signed-off-by: NFlorian Fainelli <f.fainelli@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Modern hardware can decide to drop packets going to/from a VF.
Add receive and transmit drop counters to be displayed at hypervisor
layer in iproute2 per VF statistics.
Signed-off-by: NEugenia Emantayev <eugenia@mellanox.com>
Signed-off-by: NSaeed Mahameed <saeedm@mellanox.com>

This function is used from two places: rtnl_dump_ifinfo and
rtnl_getlink. In rtnl_getlink(), we give a request skb into
get_target_net(), but in rtnl_dump_ifinfo, we give a response skb
into get_target_net().
The problem here is that NETLINK_CB() isn't initialized for the response
skb. In both cases we can get a user socket and give it instead of skb
into get_target_net().

This bug was found by syzkaller with this call-trace:

kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] SMP KASAN
Modules linked in:
CPU: 1 PID: 3149 Comm: syzkaller140561 Not tainted 4.15.0-rc4-mm1+ #47
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
RIP: 0010:__netlink_ns_capable+0x8b/0x120 net/netlink/af_netlink.c:868
RSP: 0018:ffff8801c880f348 EFLAGS: 00010206
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffffff8443f900
RDX: 000000000000007b RSI: ffffffff86510f40 RDI: 00000000000003d8
RBP: ffff8801c880f360 R08: 0000000000000000 R09: 1ffff10039101e4f
R10: 0000000000000000 R11: 0000000000000001 R12: ffffffff86510f40
R13: 000000000000000c R14: 0000000000000004 R15: 0000000000000011
FS:  0000000001a1a880(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020151000 CR3: 00000001c9511005 CR4: 00000000001606e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
  netlink_ns_capable+0x26/0x30 net/netlink/af_netlink.c:886
  get_target_net+0x9d/0x120 net/core/rtnetlink.c:1765
  rtnl_dump_ifinfo+0x2e5/0xee0 net/core/rtnetlink.c:1806
  netlink_dump+0x48c/0xce0 net/netlink/af_netlink.c:2222
  __netlink_dump_start+0x4f0/0x6d0 net/netlink/af_netlink.c:2319
  netlink_dump_start include/linux/netlink.h:214 [inline]
  rtnetlink_rcv_msg+0x7f0/0xb10 net/core/rtnetlink.c:4485
  netlink_rcv_skb+0x21e/0x460 net/netlink/af_netlink.c:2441
  rtnetlink_rcv+0x1c/0x20 net/core/rtnetlink.c:4540
  netlink_unicast_kernel net/netlink/af_netlink.c:1308 [inline]
  netlink_unicast+0x4be/0x6a0 net/netlink/af_netlink.c:1334
  netlink_sendmsg+0xa4a/0xe60 net/netlink/af_netlink.c:1897

Cc: Jiri Benc <jbenc@redhat.com>
Fixes: 79e1ad14 ("rtnetlink: use netnsid to query interface")
Signed-off-by: NAndrei Vagin <avagin@openvz.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Fixes: 46e6b992 ("rtnetlink: allow GSO maximums to be set on device creation")
Signed-off-by: NStephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Netlink device already allows changing GSO sizes with
ip set command. The part that is missing is allowing overriding
GSO settings on device creation.
Signed-off-by: NStephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Incorrect/missing annotations caused a few sparse warnings:

rtnetlink.c:155:15: incompatible types .. (different address spaces)
rtnetlink.c:157:23: incompatible types .. (different address spaces)
rtnetlink.c:185:15: incompatible types .. (different address spaces)
rtnetlink.c:285:15: incompatible types .. (different address spaces)
rtnetlink.c:317:9: incompatible types .. (different address spaces)
rtnetlink.c:3054:23: incompatible types .. (different address spaces)

no change in generated code.

Fixes: addf9b90 ("net: rtnetlink: use rcu to free rtnl message handlers")
Reported-by: Nkbuild test robot <fengguang.wu@intel.com>
Signed-off-by: NFlorian Westphal <fw@strlen.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

convert remaining users of rtnl_register to rtnl_register_module
and un-export rtnl_register.
Requested-by: NDavid S. Miller <davem@davemloft.net>
Signed-off-by: NFlorian Westphal <fw@strlen.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This removes __rtnl_register and switches callers to either
rtnl_register or rtnl_register_module.

Also, rtnl_register() will now print an error if memory allocation
failed rather than panic the kernel.
Signed-off-by: NFlorian Westphal <fw@strlen.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Add yet another rtnl_register function.  It will be used by modules
that can be removed.

The passed module struct is used to prevent module unload while
a netlink dump is in progress or when a DOIT_UNLOCKED doit callback
is called.

Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: NFlorian Westphal <fw@strlen.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

rtnetlink is littered with READ_ONCE() because we can have read accesses
while another cpu can write to the structure we're reading by
(un)registering doit or dumpit handlers.

This patch changes this so that (un)registering cpu allocates a new
structure and then publishes it via rcu_assign_pointer, i.e. once
another cpu can see such pointer no modifications will occur anymore.

based on initial patch from Peter Zijlstra.

Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: NFlorian Westphal <fw@strlen.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The output parameters will get unwieldy if we want to add more
information about the program.  Simply pass the entire
struct netdev_bpf in.
Signed-off-by: NJakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: NSimon Horman <simon.horman@netronome.com>
Reviewed-by: NQuentin Monnet <quentin.monnet@netronome.com>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>

The size for IFLA_IF_NETNSID is missing from the size calculation
because the proceeding semicolon was not removed. Fix this by removing
the semicolon.

Detected by CoverityScan, CID#1461135 ("Structurally dead code")

Fixes: 79e1ad14 ("rtnetlink: use netnsid to query interface")
Signed-off-by: NColin Ian King <colin.king@canonical.com>
Acked-by: NJiri Benc <jbenc@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

ndo_xdp is a control path callback for setting up XDP in the
driver.  We can reuse it for other forms of communication
between the eBPF stack and the drivers.  Rename the callback
and associated structures and definitions.
Signed-off-by: NJakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: NSimon Horman <simon.horman@netronome.com>
Reviewed-by: NQuentin Monnet <quentin.monnet@netronome.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Currently, when an application gets netnsid from the kernel (for example as
the result of RTM_GETLINK call on one end of the veth pair), it's not much
useful. There's no reliable way to get to the netns fd from the netnsid, nor
does any kernel API accept netnsid.

Extend the RTM_GETLINK call to also accept netnsid. It will operate on the
netns with the given netnsid in such case. Of course, the calling process
needs to have enough capabilities in the target name space; for now, require
CAP_NET_ADMIN. This can be relaxed in the future.

To signal to the calling process that the kernel understood the new
IFLA_IF_NETNSID attribute in the query, it will include it in the response.
This is needed to detect older kernels, as they will just ignore
IFLA_IF_NETNSID and query in the current name space.

This patch implemetns IFLA_IF_NETNSID only for get and dump. For set
operations, this can be extended later.
Signed-off-by: NJiri Benc <jbenc@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

After the patch 'rtnetlink: bring NETDEV_CHANGELOWERSTATE event
process back to rtnetlink_event', bond_lower_state_changed would
generate NETDEV_CHANGEUPPER event which would send a notification
to userspace in rtnetlink_event.

There's no need to call rtmsg_ifinfo to send the notification
any more. So this patch is to remove it from these places after
bond_lower_state_changed.

Besides, after this, rtmsg_ifinfo is not needed to be exported.
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch is to bring NETDEV_CHANGELOWERSTATE event process back
to rtnetlink_event so that bonding could use it instead of calling
rtmsg_ifinfo to send a notification to userspace after netdev lower
state is changed in the later patch.
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Use BUG_ON instead of if condition followed by BUG in do_setlink.

This issue was detected with the help of Coccinelle.
Signed-off-by: NGustavo A. R. Silva <garsilva@embeddedor.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

rtnl af_ops currently rely on rtnl mutex: unregister (called from module
exit functions) takes the rtnl mutex and all users that do af_ops lookup
also take the rtnl mutex. IOW, parallel rmmod will block until doit()
callback is done.

As none of the af_ops implementation sleep we can use rcu instead.

doit functions that need the af_ops can now use rcu instead of the
rtnl mutex provided the mutex isn't needed for other reasons.
Signed-off-by: NFlorian Westphal <fw@strlen.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

next patch will rcu-ify rtnl af_ops, i.e. allow af_ops
lookup and function calls with rcu read lock held instead
of rtnl mutex.
Signed-off-by: NFlorian Westphal <fw@strlen.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

IFLA_IFALIAS is defined as NLA_STRING. It means that the minimal length of
the attribute is 1 ("\0"). However, to remove an alias, the attribute
length must be 0 (see dev_set_alias()).

Let's define the type to NLA_BINARY to allow 0-length string, so that the
alias can be removed.

Example:
$ ip l s dummy0 alias foo
$ ip l l dev dummy0
5: dummy0: <BROADCAST,NOARP> mtu 1500 qdisc noop state DOWN mode DEFAULT group default qlen 1000
    link/ether ae:20:30:4f:a7:f3 brd ff:ff:ff:ff:ff:ff
    alias foo

Before the patch:
$ ip l s dummy0 alias ""
RTNETLINK answers: Numerical result out of range

After the patch:
$ ip l s dummy0 alias ""
$ ip l l dev dummy0
5: dummy0: <BROADCAST,NOARP> mtu 1500 qdisc noop state DOWN mode DEFAULT group default qlen 1000
    link/ether ae:20:30:4f:a7:f3 brd ff:ff:ff:ff:ff:ff

CC: Oliver Hartkopp <oliver@hartkopp.net>
CC: Stephen Hemminger <stephen@networkplumber.org>
Fixes: 96ca4a2c ("net: remove ifalias on empty given alias")
Reported-by: NJulien FLoret <julien.floret@6wind.com>
Signed-off-by: NNicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

NETDEV_CHANGE_TX_QUEUE_LEN event process in rtnetlink_event would
send a notification for userspace and tx_queue_len's setting in
do_setlink would trigger NETDEV_CHANGE_TX_QUEUE_LEN.

So it shouldn't set DO_SETLINK_NOTIFY status for this change to
send a notification any more.
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Acked-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The check 'status & DO_SETLINK_NOTIFY' in do_setlink doesn't really
work after status & DO_SETLINK_MODIFIED, as:

  DO_SETLINK_MODIFIED 0x1
  DO_SETLINK_NOTIFY 0x3

Considering that notifications are suppposed to be sent only when
status have the flag DO_SETLINK_NOTIFY, the right check would be:

  (status & DO_SETLINK_NOTIFY) == DO_SETLINK_NOTIFY

This would avoid lots of duplicated notifications when setting some
properties of a link.

Fixes: ba998906 ("rtnl/do_setlink(): notify when a netdev is modified")
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Acked-by: NDavid Ahern <dsahern@gmail.com>
Acked-by: NNicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

libteam needs this event notification in userspace when dev's master
dev has been changed. After this, the redundant notifications issue
would be fixed in the later patch 'rtnetlink: check DO_SETLINK_NOTIFY
correctly in do_setlink'.

Fixes: b6b36eb2 ("rtnetlink: Do not generate notifications for NETDEV_CHANGEUPPER event")
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Acked-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

As I said in patch 'rtnetlink: bring NETDEV_CHANGEMTU event process back
in rtnetlink_event', removing NETDEV_POST_TYPE_CHANGE event was not the
right fix for the redundant notifications issue.

So bring this event process back to rtnetlink_event and the old redundant
notifications issue would be fixed in the later patch 'rtnetlink: check
DO_SETLINK_NOTIFY correctly in do_setlink'.

Fixes: aef091ae ("rtnetlink: Do not generate notifications for POST_TYPE_CHANGE event")
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Acked-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The same fix for changing mtu in the patch 'rtnetlink: bring
NETDEV_CHANGEMTU event process back in rtnetlink_event' is
needed for changing tx_queue_len.

Note that the redundant notifications issue for tx_queue_len
will be fixed in the later patch 'rtnetlink: do not send
notification for tx_queue_len in do_setlink'.

Fixes: 27b3b551 ("rtnetlink: Do not generate notifications for NETDEV_CHANGE_TX_QUEUE_LEN event")
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Acked-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Commit 085e1a65 ("rtnetlink: Do not generate notifications for MTU
events") tried to fix the redundant notifications issue when ip link
set mtu by removing NETDEV_CHANGEMTU event process in rtnetlink_event.

But it also resulted in no notification generated when dev's mtu is
changed via other methods, like:
  'ifconfig eth1 mtu 1400' or 'echo 1400 > /sys/class/net/eth1/mtu'
It would cause users not to be notified by this change.

This patch is to fix it by bringing NETDEV_CHANGEMTU event back into
rtnetlink_event, and the redundant notifications issue will be fixed
in the later patch 'rtnetlink: check DO_SETLINK_NOTIFY correctly in
do_setlink'.

Fixes: 085e1a65 ("rtnetlink: Do not generate notifications for MTU events")
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

We can now piggyback error strings to userspace via extended acks
rather than using printk.

Before:
bridge fdb add 01:02:03:04:05:06 dev br0 vlan 4095
RTNETLINK answers: Invalid argument

After:
bridge fdb add 01:02:03:04:05:06 dev br0 vlan 4095
Error: invalid vlan id.

v3: drop 'RTM_' prefixes, suggested by David Ahern, they
are not useful, the add/del in bridge command line is enough.

Also reword error in response to malformed/bad vlan id attribute
size.

Cc: David Ahern <dsahern@gmail.com>
Signed-off-by: NFlorian Westphal <fw@strlen.de>
Reviewed-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Pass extack to do_set_master and down to ndo_add_slave
Signed-off-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

x-netns interfaces are bound to two netns: the link netns and the upper
netns. Usually, this kind of interfaces is created in the link netns and
then moved to the upper netns. At the end, the interface is visible only
in the upper netns. The link nsid is advertised via netlink in the upper
netns, thus the user always knows where is the link part.

There is no such mechanism in the link netns. When the interface is moved
to another netns, the user cannot "follow" it.
This patch adds a new netlink attribute which helps to follow an interface
which moves to another netns. When the interface is unregistered, the new
nsid is advertised. If the interface is a x-netns interface (ie
rtnl_link_ops->get_link_net is defined), the nsid is allocated if needed.

CC: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: NNicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

switch the only caller to rtnl_af_unregister.
Signed-off-by: NFlorian Westphal <fw@strlen.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

no users in the tree.
Signed-off-by: NFlorian Westphal <fw@strlen.de>
Acked-by: NJiri Pirko <jiri@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Device alias can be set by either rtnetlink (rtnl is held) or sysfs.

rtnetlink hold the rtnl mutex, sysfs acquires it for this purpose.
Add an extra mutex for it and use rcu to protect concurrent accesses.

This allows the sysfs path to not take rtnl and would later allow
to not hold it when dumping ifalias.

Based on suggestion from Eric Dumazet.
Signed-off-by: NFlorian Westphal <fw@strlen.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When RTM_GETSTATS was added the fields of its header struct were not all
initialized when returning the result thus leaking 4 bytes of information
to user-space per rtnl_fill_statsinfo call, so initialize them now. Thanks
to Alexander Potapenko for the detailed report and bisection.
Reported-by: NAlexander Potapenko <glider@google.com>
Fixes: 10c9ead9 ("rtnetlink: add new RTM_GETSTATS message to dump link stats")
Signed-off-by: NNikolay Aleksandrov <nikolay@cumulusnetworks.com>
Acked-by: NRoopa Prabhu <roopa@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

it can be switched to rcu.
Reviewed-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NFlorian Westphal <fw@strlen.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Reviewed-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NFlorian Westphal <fw@strlen.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

similar to earlier patches, split out more parts of this function to
better see what is happening and where we assume rtnl is locked.
Reviewed-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NFlorian Westphal <fw@strlen.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>