sctp: fix an issue that plpmtu can never go to complete state

When doing plpmtu probe, the probe size is growing every time when it
receives the ACK during the Search state until the probe fails. Wh

sctp: fix an issue that plpmtu can never go to complete state

When doing plpmtu probe, the probe size is growing every time when it
receives the ACK during the Search state until the probe fails. When
the failure occurs, pl.probe_high is set and it goes to the Complete
state.

However, if the link pmtu is huge, like 65535 in loopback_dev, the probe
eventually keeps using SCTP_MAX_PLPMTU as the probe size and never fails.
Because of that, pl.probe_high can not be set, and the plpmtu probe can
never go to the Complete state.

Fix it by setting pl.probe_high to SCTP_MAX_PLPMTU when the probe size
grows to SCTP_MAX_PLPMTU in sctp_transport_pl_recv(). Also, not allow
the probe size greater than SCTP_MAX_PLPMTU in the Complete state.

Fixes: b87641aff9e7 ("sctp: do state transition when a probe succeeds on HB ACK recv path")
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

show more ...

sctp: do not check hb_timer.expires when resetting hb_timer

It tries to avoid the frequently hb_timer refresh in commit ba6f5e33bdbb
("sctp: avoid refreshing heartbeat timer too often"), and it only

sctp: do not check hb_timer.expires when resetting hb_timer

It tries to avoid the frequently hb_timer refresh in commit ba6f5e33bdbb
("sctp: avoid refreshing heartbeat timer too often"), and it only allows
mod_timer when the new expires is after hb_timer.expires. It means even
a much shorter interval for hb timer gets applied, it will have to wait
until the current hb timer to time out.

In sctp_do_8_2_transport_strike(), when a transport enters PF state, it
expects to update the hb timer to resend a heartbeat every rto after
calling sctp_transport_reset_hb_timer(), which will not work as the
change mentioned above.

The frequently hb_timer refresh was caused by sctp_transport_reset_timers()
called in sctp_outq_flush() and it was already removed in the commit above.
So we don't have to check hb_timer.expires when resetting hb_timer as it is
now not called very often.

Fixes: ba6f5e33bdbb ("sctp: avoid refreshing heartbeat timer too often")
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Link: https://lore.kernel.org/r/d958c06985713ec84049a2d5664879802710179a.1675095933.git.lucien.xin@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

show more ...

treewide: use get_random_u32_below() instead of deprecated function

This is a simple mechanical transformation done by:

@@
expression E;
@@
- prandom_u32_max
+ get_random_u32_below
(E)

Reviewed-

treewide: use get_random_u32_below() instead of deprecated function

This is a simple mechanical transformation done by:

@@
expression E;
@@
- prandom_u32_max
+ get_random_u32_below
(E)

Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Darrick J. Wong <djwong@kernel.org> # for xfs
Reviewed-by: SeongJae Park <sj@kernel.org> # for damon
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> # for infiniband
Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk> # for arm
Acked-by: Ulf Hansson <ulf.hansson@linaro.org> # for mmc
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

show more ...

sctp: make the raise timer more simple and accurate

Currently, the probe timer is reused as the raise timer when PLPMTUD is in
the Search Complete state. raise_count was introduced to count how many

sctp: make the raise timer more simple and accurate

Currently, the probe timer is reused as the raise timer when PLPMTUD is in
the Search Complete state. raise_count was introduced to count how many
times the probe timer has timed out. When raise_count reaches to 30, the
raise timer handler will be triggered.

During the whole processing above, the timer keeps timing out every probe_
interval. It is a waste for the Search Complete state, as the raise timer
only needs to time out after 30 * probe_interval.

Since the raise timer and probe timer are never used at the same time, it
is no need to keep probe timer 'alive' in the Search Complete state. This
patch to introduce sctp_transport_reset_raise_timer() to start the timer
as the raise timer when entering the Search Complete state. When entering
the other states, sctp_transport_reset_probe_timer() will still be called
to reset the timer to the probe timer.

raise_count can be removed from sctp_transport as no need to count probe
timer timeout for raise timer timeout. last_rtx_chunks can be removed as
sctp_transport_reset_probe_timer() can be called in the place where asoc
rtx_data_chunks is changed.

Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Link: https://lore.kernel.org/r/edb0e48988ea85997488478b705b11ddc1ba724a.1637781974.git.lucien.xin@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

show more ...

sctp: return true only for pathmtu update in sctp_transport_pl_toobig

sctp_transport_pl_toobig() supposes to return true only if there's
pathmtu update, so that in sctp_icmp_frag_needed() it would c

sctp: return true only for pathmtu update in sctp_transport_pl_toobig

sctp_transport_pl_toobig() supposes to return true only if there's
pathmtu update, so that in sctp_icmp_frag_needed() it would call
sctp_assoc_sync_pmtu() and sctp_retransmit(). This patch is to fix
these return places in sctp_transport_pl_toobig().

Fixes: 836964083177 ("sctp: do state transition when receiving an icmp TOOBIG packet")
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

show more ...

sctp: allow IP fragmentation when PLPMTUD enters Error state

Currently when PLPMTUD enters Error state, transport pathmtu will be set
to MIN_PLPMTU(512) while probe is continuing with BASE_PLPMTU(12

sctp: allow IP fragmentation when PLPMTUD enters Error state

Currently when PLPMTUD enters Error state, transport pathmtu will be set
to MIN_PLPMTU(512) while probe is continuing with BASE_PLPMTU(1200). It
will cause pathmtu to stay in a very small value, even if the real pmtu
is some value like 1000.

RFC8899 doesn't clearly say how to set the value in Error state. But one
possibility could be keep using BASE_PLPMTU for the real pmtu, but allow
to do IP fragmentation when it's in Error state.

As it says in rfc8899#section-5.4:

Some paths could be unable to sustain packets of the BASE_PLPMTU
size. The Error State could be implemented to provide robustness to
such paths. This allows fallback to a smaller than desired PLPMTU
rather than suffer connectivity failure. This could utilize methods
such as endpoint IP fragmentation to enable the PL sender to
communicate using packets smaller than the BASE_PLPMTU.

This patch is to set pmtu to BASE_PLPMTU instead of MIN_PLPMTU for Error
state in sctp_transport_pl_send/toobig(), and set packet ipfragok for
non-probe packets when it's in Error state.

Fixes: 1dc68c194571 ("sctp: do state transition when PROBE_COUNT == MAX_PROBES on HB send path")
Reported-by: Ying Xu <yinxu@redhat.com>
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

show more ...

sctp: return true only for pathmtu update in sctp_transport_pl_toobig

[ Upstream commit 75cf662c64dd8543f56c329c69eba18141c8fd9f ]

sctp_transport_pl_toobig() supposes to return true only if there's

sctp: return true only for pathmtu update in sctp_transport_pl_toobig

[ Upstream commit 75cf662c64dd8543f56c329c69eba18141c8fd9f ]

sctp_transport_pl_toobig() supposes to return true only if there's
pathmtu update, so that in sctp_icmp_frag_needed() it would call
sctp_assoc_sync_pmtu() and sctp_retransmit(). This patch is to fix
these return places in sctp_transport_pl_toobig().

Fixes: 836964083177 ("sctp: do state transition when receiving an icmp TOOBIG packet")
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>

show more ...

sctp: allow IP fragmentation when PLPMTUD enters Error state

[ Upstream commit 40171248bb8934537fec8fbaf718e57c8add187c ]

Currently when PLPMTUD enters Error state, transport pathmtu will be set
to

sctp: allow IP fragmentation when PLPMTUD enters Error state

[ Upstream commit 40171248bb8934537fec8fbaf718e57c8add187c ]

Currently when PLPMTUD enters Error state, transport pathmtu will be set
to MIN_PLPMTU(512) while probe is continuing with BASE_PLPMTU(1200). It
will cause pathmtu to stay in a very small value, even if the real pmtu
is some value like 1000.

RFC8899 doesn't clearly say how to set the value in Error state. But one
possibility could be keep using BASE_PLPMTU for the real pmtu, but allow
to do IP fragmentation when it's in Error state.

As it says in rfc8899#section-5.4:

Some paths could be unable to sustain packets of the BASE_PLPMTU
size. The Error State could be implemented to provide robustness to
such paths. This allows fallback to a smaller than desired PLPMTU
rather than suffer connectivity failure. This could utilize methods
such as endpoint IP fragmentation to enable the PL sender to
communicate using packets smaller than the BASE_PLPMTU.

This patch is to set pmtu to BASE_PLPMTU instead of MIN_PLPMTU for Error
state in sctp_transport_pl_send/toobig(), and set packet ipfragok for
non-probe packets when it's in Error state.

Fixes: 1dc68c194571 ("sctp: do state transition when PROBE_COUNT == MAX_PROBES on HB send path")
Reported-by: Ying Xu <yinxu@redhat.com>
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>

show more ...

sctp: send pmtu probe only if packet loss in Search Complete state

This patch is to introduce last_rtx_chunks into sctp_transport to detect
if there's any packet retransmission/loss happened by chec

sctp: send pmtu probe only if packet loss in Search Complete state

This patch is to introduce last_rtx_chunks into sctp_transport to detect
if there's any packet retransmission/loss happened by checking against
asoc's rtx_data_chunks in sctp_transport_pl_send().

If there is, namely, transport->last_rtx_chunks != asoc->rtx_data_chunks,
the pmtu probe will be sent out. Otherwise, increment the pl.raise_count
and return when it's in Search Complete state.

With this patch, if in Search Complete state, which is a long period, it
doesn't need to keep probing the current pmtu unless there's data packet
loss. This will save quite some traffic.

v1->v2:
- add the missing Fixes tag.

Fixes: 0dac127c0557 ("sctp: do black hole detection in search complete state")
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

show more ...

sctp: improve the code for pmtu probe send and recv update

This patch does 3 things:

- make sctp_transport_pl_send() and sctp_transport_pl_recv()
return bool type to decide if more probe is n

sctp: improve the code for pmtu probe send and recv update

This patch does 3 things:

- make sctp_transport_pl_send() and sctp_transport_pl_recv()
return bool type to decide if more probe is needed to send.

- pr_debug() only when probe is really needed to send.

- count pl.raise_count in sctp_transport_pl_send() instead of
sctp_transport_pl_recv(), and it's only incremented for the
1st probe for the same size.

These are preparations for the next patch to make probes happen
only when there's packet loss in Search Complete state.

Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

show more ...

sctp: check pl.raise_count separately from its increment

As Marcelo's suggestion this will make code more clear to read.

Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Marcelo Ricardo Lei

sctp: check pl.raise_count separately from its increment

As Marcelo's suggestion this will make code more clear to read.

Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

show more ...

sctp: do black hole detection in search complete state

Currently the PLPMUTD probe will stop for a long period (interval * 30)
after it enters search complete state. If there's a pmtu change on the

sctp: do black hole detection in search complete state

Currently the PLPMUTD probe will stop for a long period (interval * 30)
after it enters search complete state. If there's a pmtu change on the
route path, it takes a long time to be aware if the ICMP TooBig packet
is lost or filtered.

As it says in rfc8899#section-4.3:

"A DPLPMTUD method MUST NOT rely solely on this method."
(ICMP PTB message).

This patch is to enable the other method for search complete state:

"A PL can use the DPLPMTUD probing mechanism to periodically
generate probe packets of the size of the current PLPMTU."

With this patch, the probe will continue with the current pmtu every
'interval' until the PMTU_RAISE_TIMER 'timeout', which we implement
by adding raise_count to raise the probe size when it counts to 30
and removing the SCTP_PL_COMPLETE check for PMTU_RAISE_TIMER.

Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

show more ...

sctp: enable PLPMTUD when the transport is ready

sctp_transport_pl_reset() is called whenever any of these 3 members in
transport is changed:

- probe_interval
- param_flags & SPP_PMTUD_ENABLE

sctp: enable PLPMTUD when the transport is ready

sctp_transport_pl_reset() is called whenever any of these 3 members in
transport is changed:

- probe_interval
- param_flags & SPP_PMTUD_ENABLE
- state == ACTIVE

If all are true, start the PLPMTUD when it's not yet started. If any of
these is false, stop the PLPMTUD when it's already running.

sctp_transport_pl_update() is called when the transport dst has changed.
It will restart the PLPMTUD probe. Again, the pathmtu won't change but
use the dst's mtu until the Search phase is done.

Note that after using PLPMTUD, the pathmtu is only initialized with the
dst mtu when the transport dst changes. At other time it is updated by
pl.pmtu. So sctp_transport_pmtu_check() will be called only when PLPMTUD
is disabled in sctp_packet_config().

After this patch, the PLPMTUD feature from RFC8899 will be activated
and can be used by users.

Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

show more ...

sctp: do state transition when receiving an icmp TOOBIG packet

PLPMTUD will short-circuit the old process for icmp TOOBIG packets.
This part is described in rfc8899#section-4.6.2 (PL_PTB_SIZE =
PTB_

sctp: do state transition when receiving an icmp TOOBIG packet

PLPMTUD will short-circuit the old process for icmp TOOBIG packets.
This part is described in rfc8899#section-4.6.2 (PL_PTB_SIZE =
PTB_SIZE - other_headers_len). Note that from rfc8899#section-5.2
State Machine, each case below is for some specific states only:

a) PL_PTB_SIZE < MIN_PLPMTU || PL_PTB_SIZE >= PROBED_SIZE,
discard it, for any state

b) MIN_PLPMTU < PL_PTB_SIZE < BASE_PLPMTU,
Base -> Error, for Base state

c) BASE_PLPMTU <= PL_PTB_SIZE < PLPMTU,
Search -> Base or Complete -> Base, for Search and Complete states.

d) PLPMTU < PL_PTB_SIZE < PROBED_SIZE,
set pl.probe_size to PL_PTB_SIZE then verify it, for Search state.

The most important one is case d), which will help find the optimal
fast during searching. Like when pathmtu = 1392 for SCTP over IPv4,
the search will be (20 is iphdr_len):

1. probe with 1200 - 20
2. probe with 1232 - 20
3. probe with 1264 - 20
...
7. probe with 1388 - 20
8. probe with 1420 - 20

When sending the probe with 1420 - 20, TOOBIG may come with PL_PTB_SIZE =
1392 - 20. Then it matches case d), and saves some rounds to try with the
1392 - 20 probe. But of course, PLPMTUD doesn't trust TOOBIG packets, and
it will go back to the common searching once the probe with the new size
can't be verified.

Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

show more ...

sctp: do state transition when a probe succeeds on HB ACK recv path

As described in rfc8899#section-5.2, when a probe succeeds, there might
be the following state transitions:

- Base -> Search, o

sctp: do state transition when a probe succeeds on HB ACK recv path

As described in rfc8899#section-5.2, when a probe succeeds, there might
be the following state transitions:

- Base -> Search, occurs when probe succeeds with BASE_PLPMTU,
pl.pmtu is not changing,
pl.probe_size increases by SCTP_PL_BIG_STEP,

- Error -> Search, occurs when probe succeeds with BASE_PLPMTU,
pl.pmtu is changed from SCTP_MIN_PLPMTU to SCTP_BASE_PLPMTU,
pl.probe_size increases by SCTP_PL_BIG_STEP.

- Search -> Search Complete, occurs when probe succeeds with the probe
size SCTP_MAX_PLPMTU less than pl.probe_high,
pl.pmtu is not changing, but update *pathmtu* with it,
pl.probe_size is set back to pl.pmtu to double check it.

- Search Complete -> Search, occurs when probe succeeds with the probe
size equal to pl.pmtu,
pl.pmtu is not changing,
pl.probe_size increases by SCTP_PL_MIN_STEP.

So search process can be described as:

1. When it just enters 'Search' state, *pathmtu* is not updated with
pl.pmtu, and probe_size increases by a big step (SCTP_PL_BIG_STEP)
each round.

2. Until pl.probe_high is set when a probe fails, and probe_size
decreases back to pl.pmtu, as described in the last patch.

3. When the probe with the new size succeeds, probe_size changes to
increase by a small step (SCTP_PL_MIN_STEP) due to pl.probe_high
is set.

4. Until probe_size is next to pl.probe_high, the searching finishes and
it goes to 'Complete' state and updates *pathmtu* with pl.pmtu, and
then probe_size is set to pl.pmtu to confirm by once more probe.

5. This probe occurs after "30 * probe_inteval", a much longer time than
that in Search state. Once it is done it goes to 'Search' state again
with probe_size increased by SCTP_PL_MIN_STEP.

As we can see above, during the searching, pl.pmtu changes while *pathmtu*
doesn't. *pathmtu* is only updated when the search finishes by which it
gets an optimal value for it. A big step is used at the beginning until
it gets close to the optimal value, then it changes to a small step until
it has this optimal value.

The small step is also used in 'Complete' until it goes to 'Search' state
again and the probe with 'pmtu + the small step' succeeds, which means a
higher size could be used. Then probe_size changes to increase by a big
step again until it gets close to the next optimal value.

Note that anytime when black hole is detected, it goes directly to 'Base'
state with pl.pmtu set to SCTP_BASE_PLPMTU, as described in the last patch.

Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

show more ...

sctp: do state transition when PROBE_COUNT == MAX_PROBES on HB send path

The state transition is described in rfc8899#section-5.2,
PROBE_COUNT == MAX_PROBES means the probe fails for MAX times, and

sctp: do state transition when PROBE_COUNT == MAX_PROBES on HB send path

The state transition is described in rfc8899#section-5.2,
PROBE_COUNT == MAX_PROBES means the probe fails for MAX times, and the
state transition includes:

- Base -> Error, occurs when BASE_PLPMTU Confirmation Fails,
pl.pmtu is set to SCTP_MIN_PLPMTU,
probe_size is still SCTP_BASE_PLPMTU;

- Search -> Base, occurs when Black Hole Detected,
pl.pmtu is set to SCTP_BASE_PLPMTU,
probe_size is set back to SCTP_BASE_PLPMTU;

- Search Complete -> Base, occurs when Black Hole Detected
pl.pmtu is set to SCTP_BASE_PLPMTU,
probe_size is set back to SCTP_BASE_PLPMTU;

Note a black hole is encountered when a sender is unaware that packets
are not being delivered to the destination endpoint. So it includes the
probe failures with equal probe_size to pl.pmtu, and definitely not
include that with greater probe_size than pl.pmtu. The later one is the
normal probe failure where probe_size should decrease back to pl.pmtu
and pl.probe_high is set. pl.probe_high would be used on HB ACK recv
path in the next patch.

Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

show more ...

sctp: add the probe timer in transport for PLPMTUD

There are 3 timers described in rfc8899#section-5.1.1:

PROBE_TIMER, PMTU_RAISE_TIMER, CONFIRMATION_TIMER

This patches adds a 'probe_timer' in t

sctp: add the probe timer in transport for PLPMTUD

There are 3 timers described in rfc8899#section-5.1.1:

PROBE_TIMER, PMTU_RAISE_TIMER, CONFIRMATION_TIMER

This patches adds a 'probe_timer' in transport, and it works as either
PROBE_TIMER or PMTU_RAISE_TIMER. At most time, it works as PROBE_TIMER
and expires every a 'probe_interval' time to send the HB probe packet.
When transport pl enters COMPLETE state, it works as PMTU_RAISE_TIMER
and expires in 'probe_interval * 30' time to go back to SEARCH state
and do searching again.

SCTP HB is an acknowledged packet, CONFIRMATION_TIMER is not needed.

The timer will start when transport pl enters BASE state and stop
when it enters DISABLED state.

Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

show more ...

sctp: Fix some typo

s/tranport/transport/

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Link: https://lore.kernel.org/r/20201122180704.1366636-1-christophe.jaillet@wanadoo.fr
Si

sctp: Fix some typo

s/tranport/transport/

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Link: https://lore.kernel.org/r/20201122180704.1366636-1-christophe.jaillet@wanadoo.fr
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

show more ...

sctp: change to hold/put transport for proto_unreach_timer

A call trace was found in Hangbin's Codenomicon testing with debug kernel:

[ 2615.981988] ODEBUG: free active (active state 0) object ty

sctp: change to hold/put transport for proto_unreach_timer

A call trace was found in Hangbin's Codenomicon testing with debug kernel:

[ 2615.981988] ODEBUG: free active (active state 0) object type: timer_list hint: sctp_generate_proto_unreach_event+0x0/0x3a0 [sctp]
[ 2615.995050] WARNING: CPU: 17 PID: 0 at lib/debugobjects.c:328 debug_print_object+0x199/0x2b0
[ 2616.095934] RIP: 0010:debug_print_object+0x199/0x2b0
[ 2616.191533] Call Trace:
[ 2616.194265] <IRQ>
[ 2616.202068] debug_check_no_obj_freed+0x25e/0x3f0
[ 2616.207336] slab_free_freelist_hook+0xeb/0x140
[ 2616.220971] kfree+0xd6/0x2c0
[ 2616.224293] rcu_do_batch+0x3bd/0xc70
[ 2616.243096] rcu_core+0x8b9/0xd00
[ 2616.256065] __do_softirq+0x23d/0xacd
[ 2616.260166] irq_exit+0x236/0x2a0
[ 2616.263879] smp_apic_timer_interrupt+0x18d/0x620
[ 2616.269138] apic_timer_interrupt+0xf/0x20
[ 2616.273711] </IRQ>

This is because it holds asoc when transport->proto_unreach_timer starts
and puts asoc when the timer stops, and without holding transport the
transport could be freed when the timer is still running.

So fix it by holding/putting transport instead for proto_unreach_timer
in transport, just like other timers in transport.

v1->v2:
- Also use sctp_transport_put() for the "out_unlock:" path in
sctp_generate_proto_unreach_event(), as Marcelo noticed.

Fixes: 50b5d6ad6382 ("sctp: Fix a race between ICMP protocol unreachable and connect()")
Reported-by: Hangbin Liu <liuhangbin@gmail.com>
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Link: https://lore.kernel.org/r/102788809b554958b13b95d33440f5448113b8d6.1605331373.git.lucien.xin@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

show more ...

net: add bool confirm_neigh parameter for dst_ops.update_pmtu

The MTU update code is supposed to be invoked in response to real
networking events that update the PMTU. In IPv6 PMTU update function
_

net: add bool confirm_neigh parameter for dst_ops.update_pmtu

The MTU update code is supposed to be invoked in response to real
networking events that update the PMTU. In IPv6 PMTU update function
__ip6_rt_update_pmtu() we called dst_confirm_neigh() to update neighbor
confirmed time.

But for tunnel code, it will call pmtu before xmit, like:
- tnl_update_pmtu()
- skb_dst_update_pmtu()
- ip6_rt_update_pmtu()
- __ip6_rt_update_pmtu()
- dst_confirm_neigh()

If the tunnel remote dst mac address changed and we still do the neigh
confirm, we will not be able to update neigh cache and ping6 remote
will failed.

So for this ip_tunnel_xmit() case, _EVEN_ if the MTU is changed, we
should not be invoking dst_confirm_neigh() as we have no evidence
of successful two-way communication at this point.

On the other hand it is also important to keep the neigh reachability fresh
for TCP flows, so we cannot remove this dst_confirm_neigh() call.

To fix the issue, we have to add a new bool parameter for dst_ops.update_pmtu
to choose whether we should do neigh update or not. I will add the parameter
in this patch and set all the callers to true to comply with the previous
way, and fix the tunnel code one by one on later patches.

v5: No change.
v4: No change.
v3: Do not remove dst_confirm_neigh, but add a new bool parameter in
dst_ops.update_pmtu to control whether we should do neighbor confirm.
Also split the big patch to small ones for each area.
v2: Remove dst_confirm_neigh in __ip6_rt_update_pmtu.

Suggested-by: David Miller <davem@davemloft.net>
Reviewed-by: Guillaume Nault <gnault@redhat.com>
Acked-by: David Ahern <dsahern@gmail.com>
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

show more ...

sctp: get netns from asoc and ep base

Commit 312434617cb1 ("sctp: cache netns in sctp_ep_common") set netns
in asoc and ep base since they're created, and it will never change.
It's a better way to

sctp: get netns from asoc and ep base

Commit 312434617cb1 ("sctp: cache netns in sctp_ep_common") set netns
in asoc and ep base since they're created, and it will never change.
It's a better way to get netns from asoc and ep base, comparing to
calling sock_net().

This patch is to replace them.

v1->v2:
- no change.

Suggested-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

show more ...

sctp: only copy the available addr data in sctp_transport_init

'addr' passed to sctp_transport_init is not always a whole size
of union sctp_addr, like the path:

sctp_sendmsg() ->
sctp_sendmsg_

sctp: only copy the available addr data in sctp_transport_init

'addr' passed to sctp_transport_init is not always a whole size
of union sctp_addr, like the path:

sctp_sendmsg() ->
sctp_sendmsg_new_asoc() ->
sctp_assoc_add_peer() ->
sctp_transport_new() -> sctp_transport_init()

In the next patches, we will also pass the address length of data
only to sctp_assoc_add_peer().

So sctp_transport_init() should copy the only available data from
addr to peer->ipaddr, instead of 'peer->ipaddr = *addr' which may
cause slab-out-of-bounds.

Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

show more ...

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 104

Based on 1 normalized pattern(s):

this sctp implementation is free software you can redistribute it
and or modify it under the

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 104

Based on 1 normalized pattern(s):

this sctp implementation is free software you can redistribute it
and or modify it under the terms of the gnu general public license
as published by the free software foundation either version 2 or at
your option any later version this sctp implementation is
distributed in the hope that it will be useful but without any
warranty without even the implied warranty of merchantability or
fitness for a particular purpose see the gnu general public license
for more details you should have received a copy of the gnu general
public license along with gnu cc see the file copying if not see
http www gnu org licenses

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 42 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190523091649.683323110@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

show more ...

sctp: don't compare hb_timer expire date before starting it

hb_timer might not start at all for a particular transport because its
start is conditional. In a result a node is not sending heartbeats.

sctp: don't compare hb_timer expire date before starting it

hb_timer might not start at all for a particular transport because its
start is conditional. In a result a node is not sending heartbeats.

Function sctp_transport_reset_hb_timer has two roles:
- initial start of hb_timer for a given transport,
- update expire date of hb_timer for a given transport.
The function is optimized to update timer's expire only if it is before
a new calculated one but this comparison is invalid for a timer which
has not yet started. Such a timer has expire == 0 and if a new expire
value is bigger than (MAX_JIFFIES / 2 + 2) then "time_before" macro will
fail and timer will not start resulting in no heartbeat packets send by
the node.

This was found when association was initialized within first 5 mins
after system boot due to jiffies init value which is near to MAX_JIFFIES.

Test kernel version: 4.9.154 (ARCH=arm)
hb_timer.expire = 0; //initialized, not started timer
new_expire = MAX_JIFFIES / 2 + 2; //or more
time_before(hb_timer.expire, new_expire) == false

Fixes: ba6f5e33bdbb ("sctp: avoid refreshing heartbeat timer too often")
Reported-by: Marcin Stojek <marcin.stojek@nokia.com>
Tested-by: Marcin Stojek <marcin.stojek@nokia.com>
Signed-off-by: Maciej Kwiecien <maciej.kwiecien@nokia.com>
Reviewed-by: Alexander Sverdlin <alexander.sverdlin@nokia.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

show more ...

sctp: update dst pmtu with the correct daddr

When processing pmtu update from an icmp packet, it calls .update_pmtu
with sk instead of skb in sctp_transport_update_pmtu.

However for sctp, the daddr

sctp: update dst pmtu with the correct daddr

When processing pmtu update from an icmp packet, it calls .update_pmtu
with sk instead of skb in sctp_transport_update_pmtu.

However for sctp, the daddr in the transport might be different from
inet_sock->inet_daddr or sk->sk_v6_daddr, which is used to update or
create the route cache. The incorrect daddr will cause a different
route cache created for the path.

So before calling .update_pmtu, inet_sock->inet_daddr/sk->sk_v6_daddr
should be updated with the daddr in the transport, and update it back
after it's done.

The issue has existed since route exceptions introduction.

Fixes: 4895c771c7f0 ("ipv4: Add FIB nexthop exceptions.")
Reported-by: ian.periam@dialogic.com
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

show more ...