linux.git/net/ipv6/addrconf.c, branch v5.16

net: ndisc: introduce ndisc_evict_nocarrier sysctl parameter

2021-11-02T02:57:14+00:00

In most situations the neighbor discovery cache should be cleared on a
NOCARRIER event which is currently done unconditionally. But for wireless
roams the neighbor discovery cache can and should remain intact since
the underlying network has not changed.

This patch introduces a sysctl option ndisc_evict_nocarrier which can
be disabled by a wireless supplicant during a roam. This allows packets
to be sent after a roam immediately without having to wait for
neighbor discovery.

A user reported roughly a 1 second delay after a roam before packets
could be sent out (note, on IPv4). This delay was due to the ARP
cache being cleared. During testing of this same scenario using IPv6
no delay was noticed, but regardless there is no reason to clear
the ndisc cache for wireless roams.

Signed-off-by: James Prestwood 
Reviewed-by: David Ahern 
Signed-off-by: Jakub Kicinski

gre/sit: Don't generate link-local addr if addr_gen_mode is IN6_ADDR_GEN_MODE_NONE

2021-10-22T21:10:36+00:00

When addr_gen_mode is set to IN6_ADDR_GEN_MODE_NONE, the link-local addr
should not be generated. But it isn't the case for GRE (as well as GRE6)
and SIT tunnels. Make it so that tunnels consider the addr_gen_mode,
especially for IN6_ADDR_GEN_MODE_NONE.

Do this in add_v4_addrs() to cover both GRE and SIT only if the addr
scope is link.

Signed-off-by: Stephen Suryaputra 
Acked-by: Antonio Quartulli 
Link: https://lore.kernel.org/r/20211020200618.467342-1-ssuryaextr@gmail.com
Signed-off-by: Jakub Kicinski

ipv6: constify dev_addr passing

2021-10-13T16:40:46+00:00

In preparation for netdev->dev_addr being constant
make all relevant arguments in ndisc constant.

Signed-off-by: Jakub Kicinski

ip/ip6_gre: use the same logic as SIT interfaces when computing v6LL address

2021-09-05T12:14:37+00:00

GRE interfaces are not Ether-like and therefore it is not
possible to generate the v6LL address the same way as (for example)
GRETAP devices.

With default settings, a GRE interface will attempt generating its v6LL
address using the EUI64 approach, but this will fail when the local
endpoint of the GRE tunnel is set to "any". In this case the GRE
interface will end up with no v6LL address, thus violating RFC4291.

SIT interfaces already implement a different logic to ensure that a v6LL
address is always computed.

Change the GRE v6LL generation logic to follow the same approach as SIT.
This way GRE interfaces will always have a v6LL address as well.

Behaviour of GRETAP interfaces has not been changed as they behave like
classic Ether-like interfaces.

To avoid code duplication sit_add_v4_addrs() has been renamed to
add_v4_addrs() and adapted to handle also the IP6GRE/GRE cases.

Signed-off-by: Antonio Quartulli 
Signed-off-by: David S. Miller

ipv6: add IFLA_INET6_RA_MTU to expose mtu value

2021-08-28T00:29:18+00:00

The kernel provides a "/proc/sys/net/ipv6/conf//mtu"
file, which can temporarily record the mtu value of the last
received RA message when the RA mtu value is lower than the
interface mtu, but this proc has following limitations:

(1) when the interface mtu (/sys/class/net//mtu) is
updeated, mtu6 (/proc/sys/net/ipv6/conf//mtu) will
be updated to the value of interface mtu;
(2) mtu6 (/proc/sys/net/ipv6/conf//mtu) only affect
ipv6 connection, and not affect ipv4.

Therefore, when the mtu option is carried in the RA message,
there will be a problem that the user sometimes cannot obtain
RA mtu value correctly by reading mtu6.

After this patch set, if a RA message carries the mtu option,
you can send a netlink msg which nlmsg_type is RTM_GETLINK,
and then by parsing the attribute of IFLA_INET6_RA_MTU to
get the mtu value carried in the RA message received on the
inet6 device. In addition, you can also get a link notification
when ra_mtu is updated so it doesn't have to poll.

In this way, if the MTU values that the device receives from
the network in the PCO IPv4 and the RA IPv6 procedures are
different, the user can obtain the correct ipv6 ra_mtu value
and compare the value of ra_mtu and ipv4 mtu, then the device
can use the lower MTU value for both IPv4 and IPv6.

Signed-off-by: Rocco Yue 
Reviewed-by: David Ahern 
Link: https://lore.kernel.org/r/20210827150412.9267-1-rocco.yue@mediatek.com
Signed-off-by: Jakub Kicinski

net: Remove redundant if statements

2021-08-05T12:27:50+00:00

The 'if (dev)' statement already move into dev_{put , hold}, so remove
redundant if statements.

Signed-off-by: Yajun Deng 
Signed-off-by: David S. Miller

net: add extack arg for link ops

2021-08-04T09:01:26+00:00

Pass extack arg to validate_linkmsg and validate_link_af callbacks.
If a netlink attribute has a reject_message, use the extended ack
mechanism to carry the message back to user space.

Signed-off-by: Rocco Yue 
Reviewed-by: David Ahern 
Signed-off-by: David S. Miller

ipv6: fix "'ioam6_if_id_max' defined but not used" warn

2021-07-22T09:23:47+00:00

When compiling without CONFIG_SYSCTL, this warning appears:

  net/ipv6/addrconf.c:99:12: error: 'ioam6_if_id_max' defined but not used [-Werror=unused-variable]
     99 | static u32 ioam6_if_id_max = U16_MAX;
        |            ^~~~~~~~~~~~~~~
  cc1: all warnings being treated as errors

Simply moving the declaration of this variable under ...

  #ifdef CONFIG_SYSCTL

... with other similar variables fixes the issue.

Fixes: 9ee11f0fff20 ("ipv6: ioam: Data plane support for Pre-allocated Trace")
Signed-off-by: Matthieu Baerts 
Signed-off-by: David S. Miller

ipv6: ioam: Data plane support for Pre-allocated Trace

2021-07-21T15:14:33+00:00

Implement support for processing the IOAM Pre-allocated Trace with IPv6,
see [1] and [2]. Introduce a new IPv6 Hop-by-Hop TLV option, see IANA [3].

A new per-interface sysctl is introduced. The value is a boolean to accept (=1)
or ignore (=0, by default) IPv6 IOAM options on ingress for an interface:
 - net.ipv6.conf.XXX.ioam6_enabled

Two other sysctls are introduced to define IOAM IDs, represented by an integer.
They are respectively per-namespace and per-interface:
 - net.ipv6.ioam6_id
 - net.ipv6.conf.XXX.ioam6_id

The value of the first one represents the IOAM ID of the node itself (u32; max
and default value = U32_MAX>>8, due to hop limit concatenation) while the other
represents the IOAM ID of an interface (u16; max and default value = U16_MAX).

Each "ioam6_id" sysctl has a "_wide" equivalent:
 - net.ipv6.ioam6_id_wide
 - net.ipv6.conf.XXX.ioam6_id_wide

The value of the first one represents the wide IOAM ID of the node itself (u64;
max and default value = U64_MAX>>8, due to hop limit concatenation) while the
other represents the wide IOAM ID of an interface (u32; max and default value
= U32_MAX).

The use of short and wide equivalents is not exclusive, a deployment could
choose to leverage both. For example, net.ipv6.conf.XXX.ioam6_id (short format)
could be an identifier for a physical interface, whereas
net.ipv6.conf.XXX.ioam6_id_wide (wide format) could be an identifier for a
logical sub-interface. Documentation about new sysctls is provided at the end
of this patchset.

Two relativistic hash tables are used: one for IOAM namespaces, the other for
IOAM schemas. A namespace can only have a single active schema and a schema
can only be attached to a single namespace (1:1 relationship).

  [1] https://tools.ietf.org/html/draft-ietf-ippm-ioam-ipv6-options
  [2] https://tools.ietf.org/html/draft-ietf-ippm-ioam-data
  [3] https://www.iana.org/assignments/ipv6-parameters/ipv6-parameters.xhtml#ipv6-parameters-2

Signed-off-by: Justin Iurman 
Signed-off-by: David S. Miller

memcg: enable accounting for IP address and routing-related objects

2021-07-20T13:00:38+00:00

An netadmin inside container can use 'ip a a' and 'ip r a'
to assign a large number of ipv4/ipv6 addresses and routing entries
and force kernel to allocate megabytes of unaccounted memory
for long-lived per-netdevice related kernel objects:
'struct in_ifaddr', 'struct inet6_ifaddr', 'struct fib6_node',
'struct rt6_info', 'struct fib_rules' and ip_fib caches.

These objects can be manually removed, though usually they lives
in memory till destroy of its net namespace.

It makes sense to account for them to restrict the host's memory
consumption from inside the memcg-limited container.

One of such objects is the 'struct fib6_node' mostly allocated in
net/ipv6/route.c::__ip6_ins_rt() inside the lock_bh()/unlock_bh() section:

 write_lock_bh(&table->tb6_lock);
 err = fib6_add(&table->tb6_root, rt, info, mxc);
 write_unlock_bh(&table->tb6_lock);

In this case it is not enough to simply add SLAB_ACCOUNT to corresponding
kmem cache. The proper memory cgroup still cannot be found due to the
incorrect 'in_interrupt()' check used in memcg_kmem_bypass().

Obsoleted in_interrupt() does not describe real execution context properly.
>From include/linux/preempt.h:

 The following macros are deprecated and should not be used in new code:
 in_interrupt()	- We're in NMI,IRQ,SoftIRQ context or have BH disabled

To verify the current execution context new macro should be used instead:
 in_task()	- We're in task context

Signed-off-by: Vasily Averin 
Signed-off-by: David S. Miller