mptcp: sysctl: add available_path_managers

Similarly to net.mptcp.available_schedulers, this patch adds a new one
net.mptcp.available_path_managers to list the available path managers.

Signed-off-b

mptcp: sysctl: add available_path_managers

Similarly to net.mptcp.available_schedulers, this patch adds a new one
net.mptcp.available_path_managers to list the available path managers.

Signed-off-by: Geliang Tang <[email protected]>
Reviewed-by: Matthieu Baerts (NGI0) <[email protected]>
Signed-off-by: Matthieu Baerts (NGI0) <[email protected]>
Reviewed-by: Simon Horman <[email protected]>
Link: https://patch.msgid.link/20250313-net-next-mptcp-pm-ops-intro-v1-11-f4e4a88efc50@kernel.org
Signed-off-by: Paolo Abeni <[email protected]>

show more ...

mptcp: sysctl: map pm_type to path_manager

This patch adds a new proc_handler "proc_pm_type" for "pm_type" to
map old path manager sysctl "pm_type" to the newly added "path_manager".

path_manager

mptcp: sysctl: map pm_type to path_manager

This patch adds a new proc_handler "proc_pm_type" for "pm_type" to
map old path manager sysctl "pm_type" to the newly added "path_manager".

path_manager pm_type

MPTCP_PM_TYPE_KERNEL -> "kernel"
MPTCP_PM_TYPE_USERSPACE -> "userspace"

It is important to add this to keep a compatibility with the now
deprecated pm_type sysctl knob.

Signed-off-by: Geliang Tang <[email protected]>
Reviewed-by: Matthieu Baerts (NGI0) <[email protected]>
Signed-off-by: Matthieu Baerts (NGI0) <[email protected]>
Reviewed-by: Simon Horman <[email protected]>
Link: https://patch.msgid.link/20250313-net-next-mptcp-pm-ops-intro-v1-10-f4e4a88efc50@kernel.org
Signed-off-by: Paolo Abeni <[email protected]>

show more ...

mptcp: sysctl: map path_manager to pm_type

This patch maps the newly added path manager sysctl "path_manager"
to the old one "pm_type".

path_manager pm_type

"kernel" -> MPTCP_PM_TYPE_KERNEL

mptcp: sysctl: map path_manager to pm_type

This patch maps the newly added path manager sysctl "path_manager"
to the old one "pm_type".

path_manager pm_type

"kernel" -> MPTCP_PM_TYPE_KERNEL
"userspace" -> MPTCP_PM_TYPE_USERSPACE
others -> __MPTCP_PM_TYPE_NR

It is important to add this to keep a compatibility with the now
deprecated pm_type sysctl knob.

Signed-off-by: Geliang Tang <[email protected]>
Reviewed-by: Matthieu Baerts (NGI0) <[email protected]>
Signed-off-by: Matthieu Baerts (NGI0) <[email protected]>
Reviewed-by: Simon Horman <[email protected]>
Link: https://patch.msgid.link/20250313-net-next-mptcp-pm-ops-intro-v1-9-f4e4a88efc50@kernel.org
Signed-off-by: Paolo Abeni <[email protected]>

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mptcp: sysctl: set path manager by name

Similar to net.mptcp.scheduler, a new net.mptcp.path_manager sysctl knob
is added to determine which path manager will be used by each newly
created MPTCP soc

mptcp: sysctl: set path manager by name

Similar to net.mptcp.scheduler, a new net.mptcp.path_manager sysctl knob
is added to determine which path manager will be used by each newly
created MPTCP socket by setting the name of it.

Dealing with an explicit name is easier than with a number, especially
when more PMs will be introduced.

This sysctl knob makes the old one "pm_type" deprecated.

Signed-off-by: Geliang Tang <[email protected]>
Reviewed-by: Matthieu Baerts (NGI0) <[email protected]>
Signed-off-by: Matthieu Baerts (NGI0) <[email protected]>
Reviewed-by: Simon Horman <[email protected]>
Link: https://patch.msgid.link/20250313-net-next-mptcp-pm-ops-intro-v1-8-f4e4a88efc50@kernel.org
Signed-off-by: Paolo Abeni <[email protected]>

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mptcp: blackhole: avoid checking the state twice

A small cleanup, reordering the conditions to avoid checking things
twice.

The code here is called in case of timeout on a TCP connection, before
tr

mptcp: blackhole: avoid checking the state twice

A small cleanup, reordering the conditions to avoid checking things
twice.

The code here is called in case of timeout on a TCP connection, before
triggering a retransmission. But it only acts on SYN + MPC packets.

So the conditions can be re-order to exit early in case of non-MPTCP
SYN + MPC. This also reduce the indentation levels.

Reviewed-by: Mat Martineau <[email protected]>
Signed-off-by: Matthieu Baerts (NGI0) <[email protected]>
Link: https://patch.msgid.link/20250221-net-next-mptcp-pm-misc-cleanup-3-v1-10-2b70ab1cee79@kernel.org
Signed-off-by: Jakub Kicinski <[email protected]>

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mptcp: blackhole only if 1st SYN retrans w/o MPC is accepted

The Fixes commit mentioned this:

> An MPTCP firewall blackhole can be detected if the following SYN
> retransmission after a fallback to

mptcp: blackhole only if 1st SYN retrans w/o MPC is accepted

The Fixes commit mentioned this:

> An MPTCP firewall blackhole can be detected if the following SYN
> retransmission after a fallback to "plain" TCP is accepted.

But in fact, this blackhole was detected if any following SYN
retransmissions after a fallback to TCP was accepted.

That's because 'mptcp_subflow_early_fallback()' will set 'request_mptcp'
to 0, and 'mpc_drop' will never be reset to 0 after.

This is an issue, because some not so unusual situations might cause the
kernel to detect a false-positive blackhole, e.g. a client trying to
connect to a server while the network is not ready yet, causing a few
SYN retransmissions, before reaching the end server.

Fixes: 27069e7cb3d1 ("mptcp: disable active MPTCP in case of blackhole")
Cc: [email protected]
Reviewed-by: Mat Martineau <[email protected]>
Signed-off-by: Matthieu Baerts (NGI0) <[email protected]>
Signed-off-by: Paolo Abeni <[email protected]>

show more ...

mptcp: sysctl: add syn_retrans_before_tcp_fallback

The number of SYN + MPC retransmissions before falling back to TCP was
fixed to 2. This is certainly a good default value, but having a fixed
numbe

mptcp: sysctl: add syn_retrans_before_tcp_fallback

The number of SYN + MPC retransmissions before falling back to TCP was
fixed to 2. This is certainly a good default value, but having a fixed
number can be a problem in some environments.

The current behaviour means that if all packets are dropped, there will
be:

- The initial SYN + MPC

- 2 retransmissions with MPC

- The next ones will be without MPTCP.

So typically ~3 seconds before falling back to TCP. In some networks
where some temporally blackholes are unfortunately frequent, or when a
client tries to initiate connections while the network is not ready yet,
this can cause new connections not to have MPTCP connections.

In such environments, it is now possible to increase the number of SYN
retransmissions with MPTCP options to make sure MPTCP is used.

Interesting values are:

- 0: the first retransmission will be done without MPTCP options: quite
aggressive, but also a higher risk of detecting false-positive
MPTCP blackholes.

- >= 128: all SYN retransmissions will keep the MPTCP options: back to
the < 6.12 behaviour.

The default behaviour is not changed here.

Reviewed-by: Mat Martineau <[email protected]>
Signed-off-by: Matthieu Baerts (NGI0) <[email protected]>
Link: https://patch.msgid.link/20250117-net-next-mptcp-syn_retrans_before_tcp_fallback-v1-1-ab4b187099b0@kernel.org
Signed-off-by: Jakub Kicinski <[email protected]>

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mptcp: sysctl: blackhole timeout: avoid using current->nsproxy

As mentioned in the previous commit, using the 'net' structure via
'current' is not recommended for different reasons:

- Inconsistency

mptcp: sysctl: blackhole timeout: avoid using current->nsproxy

As mentioned in the previous commit, using the 'net' structure via
'current' is not recommended for different reasons:

- Inconsistency: getting info from the reader's/writer's netns vs only
from the opener's netns.

- current->nsproxy can be NULL in some cases, resulting in an 'Oops'
(null-ptr-deref), e.g. when the current task is exiting, as spotted by
syzbot [1] using acct(2).

The 'pernet' structure can be obtained from the table->data using
container_of().

Fixes: 27069e7cb3d1 ("mptcp: disable active MPTCP in case of blackhole")
Cc: [email protected]
Link: https://lore.kernel.org/[email protected] [1]
Suggested-by: Al Viro <[email protected]>
Reviewed-by: Mat Martineau <[email protected]>
Signed-off-by: Matthieu Baerts (NGI0) <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

show more ...

mptcp: sysctl: sched: avoid using current->nsproxy

Using the 'net' structure via 'current' is not recommended for different
reasons.

First, if the goal is to use it to read or write per-netns data,

mptcp: sysctl: sched: avoid using current->nsproxy

Using the 'net' structure via 'current' is not recommended for different
reasons.

First, if the goal is to use it to read or write per-netns data, this is
inconsistent with how the "generic" sysctl entries are doing: directly
by only using pointers set to the table entry, e.g. table->data. Linked
to that, the per-netns data should always be obtained from the table
linked to the netns it had been created for, which may not coincide with
the reader's or writer's netns.

Another reason is that access to current->nsproxy->netns can oops if
attempted when current->nsproxy had been dropped when the current task
is exiting. This is what syzbot found, when using acct(2):

Oops: general protection fault, probably for non-canonical address 0xdffffc0000000005: 0000 [#1] PREEMPT SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000028-0x000000000000002f]
CPU: 1 UID: 0 PID: 5924 Comm: syz-executor Not tainted 6.13.0-rc5-syzkaller-00004-gccb98ccef0e5 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
RIP: 0010:proc_scheduler+0xc6/0x3c0 net/mptcp/ctrl.c:125
Code: 03 42 80 3c 38 00 0f 85 fe 02 00 00 4d 8b a4 24 08 09 00 00 48 b8 00 00 00 00 00 fc ff df 49 8d 7c 24 28 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 cc 02 00 00 4d 8b 7c 24 28 48 8d 84 24 c8 00 00
RSP: 0018:ffffc900034774e8 EFLAGS: 00010206

RAX: dffffc0000000000 RBX: 1ffff9200068ee9e RCX: ffffc90003477620
RDX: 0000000000000005 RSI: ffffffff8b08f91e RDI: 0000000000000028
RBP: 0000000000000001 R08: ffffc90003477710 R09: 0000000000000040
R10: 0000000000000040 R11: 00000000726f7475 R12: 0000000000000000
R13: ffffc90003477620 R14: ffffc90003477710 R15: dffffc0000000000
FS: 0000000000000000(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fee3cd452d8 CR3: 000000007d116000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
proc_sys_call_handler+0x403/0x5d0 fs/proc/proc_sysctl.c:601
__kernel_write_iter+0x318/0xa80 fs/read_write.c:612
__kernel_write+0xf6/0x140 fs/read_write.c:632
do_acct_process+0xcb0/0x14a0 kernel/acct.c:539
acct_pin_kill+0x2d/0x100 kernel/acct.c:192
pin_kill+0x194/0x7c0 fs/fs_pin.c:44
mnt_pin_kill+0x61/0x1e0 fs/fs_pin.c:81
cleanup_mnt+0x3ac/0x450 fs/namespace.c:1366
task_work_run+0x14e/0x250 kernel/task_work.c:239
exit_task_work include/linux/task_work.h:43 [inline]
do_exit+0xad8/0x2d70 kernel/exit.c:938
do_group_exit+0xd3/0x2a0 kernel/exit.c:1087
get_signal+0x2576/0x2610 kernel/signal.c:3017
arch_do_signal_or_restart+0x90/0x7e0 arch/x86/kernel/signal.c:337
exit_to_user_mode_loop kernel/entry/common.c:111 [inline]
exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
__syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
syscall_exit_to_user_mode+0x150/0x2a0 kernel/entry/common.c:218
do_syscall_64+0xda/0x250 arch/x86/entry/common.c:89
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fee3cb87a6a
Code: Unable to access opcode bytes at 0x7fee3cb87a40.
RSP: 002b:00007fffcccac688 EFLAGS: 00000202 ORIG_RAX: 0000000000000037
RAX: 0000000000000000 RBX: 00007fffcccac710 RCX: 00007fee3cb87a6a
RDX: 0000000000000041 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 0000000000000003 R08: 00007fffcccac6ac R09: 00007fffcccacac7
R10: 00007fffcccac710 R11: 0000000000000202 R12: 00007fee3cd49500
R13: 00007fffcccac6ac R14: 0000000000000000 R15: 00007fee3cd4b000
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:proc_scheduler+0xc6/0x3c0 net/mptcp/ctrl.c:125
Code: 03 42 80 3c 38 00 0f 85 fe 02 00 00 4d 8b a4 24 08 09 00 00 48 b8 00 00 00 00 00 fc ff df 49 8d 7c 24 28 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 cc 02 00 00 4d 8b 7c 24 28 48 8d 84 24 c8 00 00
RSP: 0018:ffffc900034774e8 EFLAGS: 00010206
RAX: dffffc0000000000 RBX: 1ffff9200068ee9e RCX: ffffc90003477620
RDX: 0000000000000005 RSI: ffffffff8b08f91e RDI: 0000000000000028
RBP: 0000000000000001 R08: ffffc90003477710 R09: 0000000000000040
R10: 0000000000000040 R11: 00000000726f7475 R12: 0000000000000000
R13: ffffc90003477620 R14: ffffc90003477710 R15: dffffc0000000000
FS: 0000000000000000(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fee3cd452d8 CR3: 000000007d116000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess), 1 bytes skipped:
0: 42 80 3c 38 00 cmpb $0x0,(%rax,%r15,1)
5: 0f 85 fe 02 00 00 jne 0x309
b: 4d 8b a4 24 08 09 00 mov 0x908(%r12),%r12
12: 00
13: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax
1a: fc ff df
1d: 49 8d 7c 24 28 lea 0x28(%r12),%rdi
22: 48 89 fa mov %rdi,%rdx
25: 48 c1 ea 03 shr $0x3,%rdx
* 29: 80 3c 02 00 cmpb $0x0,(%rdx,%rax,1) <-- trapping instruction
2d: 0f 85 cc 02 00 00 jne 0x2ff
33: 4d 8b 7c 24 28 mov 0x28(%r12),%r15
38: 48 rex.W
39: 8d .byte 0x8d
3a: 84 24 c8 test %ah,(%rax,%rcx,8)

Here with 'net.mptcp.scheduler', the 'net' structure is not really
needed, because the table->data already has a pointer to the current
scheduler, the only thing needed from the per-netns data.
Simply use 'data', instead of getting (most of the time) the same thing,
but from a longer and indirect way.

Fixes: 6963c508fd7a ("mptcp: only allow set existing scheduler for net.mptcp.scheduler")
Cc: [email protected]
Reported-by: [email protected]
Closes: https://lore.kernel.org/[email protected]
Suggested-by: Al Viro <[email protected]>
Reviewed-by: Mat Martineau <[email protected]>
Signed-off-by: Matthieu Baerts (NGI0) <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

show more ...

mptcp: sysctl: avail sched: remove write access

'net.mptcp.available_schedulers' sysctl knob is there to list available
schedulers, not to modify this list.

There are then no reasons to give write

mptcp: sysctl: avail sched: remove write access

'net.mptcp.available_schedulers' sysctl knob is there to list available
schedulers, not to modify this list.

There are then no reasons to give write access to it.

Nothing would have been written anyway, but no errors would have been
returned, which is unexpected.

Fixes: 73c900aa3660 ("mptcp: add net.mptcp.available_schedulers")
Cc: [email protected]
Reviewed-by: Mat Martineau <[email protected]>
Signed-off-by: Matthieu Baerts (NGI0) <[email protected]>
Reviewed-by: Eric Dumazet <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

show more ...

mptcp: disable active MPTCP in case of blackhole

An MPTCP firewall blackhole can be detected if the following SYN
retransmission after a fallback to "plain" TCP is accepted.

In case of blackhole, a

mptcp: disable active MPTCP in case of blackhole

An MPTCP firewall blackhole can be detected if the following SYN
retransmission after a fallback to "plain" TCP is accepted.

In case of blackhole, a similar technique to the one in place with TFO
is now used: MPTCP can be disabled for a certain period of time, 1h by
default. This time period will grow exponentially when more blackhole
issues get detected right after MPTCP is re-enabled and will reset to
the initial value when the blackhole issue goes away.

The blackhole period can be modified thanks to a new sysctl knob:
blackhole_timeout. Two new MIB counters help understanding what's
happening:

- 'Blackhole', incremented when a blackhole is detected.
- 'MPCapableSYNTXDisabled', incremented when an MPTCP connection
directly falls back to TCP during the blackhole period.

Because the technique is inspired by the one used by TFO, an important
part of the new code is similar to what can find in tcp_fastopen.c, with
some adaptations to the MPTCP case.

Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/57
Signed-off-by: Matthieu Baerts (NGI0) <[email protected]>
Link: https://patch.msgid.link/20240909-net-next-mptcp-fallback-x-mpc-v1-3-da7ebb4cd2a3@kernel.org
Signed-off-by: Jakub Kicinski <[email protected]>

show more ...

mptcp: fallback to TCP after SYN+MPC drops

Some middleboxes might be nasty with MPTCP, and decide to drop packets
with MPTCP options, instead of just dropping the MPTCP options (or
letting them pass

mptcp: fallback to TCP after SYN+MPC drops

Some middleboxes might be nasty with MPTCP, and decide to drop packets
with MPTCP options, instead of just dropping the MPTCP options (or
letting them pass...).

In this case, it sounds better to fallback to "plain" TCP after 2
retransmissions, and try again.

Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/477
Signed-off-by: Matthieu Baerts (NGI0) <[email protected]>
Reviewed-by: Eric Dumazet <[email protected]>
Link: https://patch.msgid.link/20240909-net-next-mptcp-fallback-x-mpc-v1-2-da7ebb4cd2a3@kernel.org
Signed-off-by: Jakub Kicinski <[email protected]>

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sysctl: treewide: constify the ctl_table argument of proc_handlers

const qualify the struct ctl_table argument in the proc_handler function
signatures. This is a prerequisite to moving the static ct

sysctl: treewide: constify the ctl_table argument of proc_handlers

const qualify the struct ctl_table argument in the proc_handler function
signatures. This is a prerequisite to moving the static ctl_table
structs into .rodata data which will ensure that proc_handler function
pointers cannot be modified.

This patch has been generated by the following coccinelle script:

```
virtual patch

@r1@
identifier ctl, write, buffer, lenp, ppos;
identifier func !~ "appldata_(timer|interval)_handler|sched_(rt|rr)_handler|rds_tcp_skbuf_handler|proc_sctp_do_(hmac_alg|rto_min|rto_max|udp_port|alpha_beta|auth|probe_interval)";
@@

int func(
- struct ctl_table *ctl
+ const struct ctl_table *ctl
,int write, void *buffer, size_t *lenp, loff_t *ppos);

@r2@
identifier func, ctl, write, buffer, lenp, ppos;
@@

int func(
- struct ctl_table *ctl
+ const struct ctl_table *ctl
,int write, void *buffer, size_t *lenp, loff_t *ppos)
{ ... }

@r3@
identifier func;
@@

int func(
- struct ctl_table *
+ const struct ctl_table *
,int , void *, size_t *, loff_t *);

@r4@
identifier func, ctl;
@@

int func(
- struct ctl_table *ctl
+ const struct ctl_table *ctl
,int , void *, size_t *, loff_t *);

@r5@
identifier func, write, buffer, lenp, ppos;
@@

int func(
- struct ctl_table *
+ const struct ctl_table *
,int write, void *buffer, size_t *lenp, loff_t *ppos);

```

* Code formatting was adjusted in xfs_sysctl.c to comply with code
conventions. The xfs_stats_clear_proc_handler,
xfs_panic_mask_proc_handler and xfs_deprecated_dointvec_minmax where
adjusted.

* The ctl_table argument in proc_watchdog_common was const qualified.
This is called from a proc_handler itself and is calling back into
another proc_handler, making it necessary to change it as part of the
proc_handler migration.

Co-developed-by: Thomas Weißschuh <[email protected]>
Signed-off-by: Thomas Weißschuh <[email protected]>
Co-developed-by: Joel Granados <[email protected]>
Signed-off-by: Joel Granados <[email protected]>

show more ...

mptcp: prefer strscpy over strcpy

strcpy() performs no bounds checking on the destination buffer. This
could result in linear overflows beyond the end of the buffer, leading
to all kinds of misbehav

mptcp: prefer strscpy over strcpy

strcpy() performs no bounds checking on the destination buffer. This
could result in linear overflows beyond the end of the buffer, leading
to all kinds of misbehaviors. The safe replacement is strscpy() [1].

This is in preparation of a possible future step where all strcpy() uses
will be removed in favour of strscpy() [2].

This fixes CheckPatch warnings:

WARNING: Prefer strscpy over strcpy

Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strcpy [1]
Link: https://github.com/KSPP/linux/issues/88 [2]
Reviewed-by: Geliang Tang <[email protected]>
Signed-off-by: Matthieu Baerts (NGI0) <[email protected]>
Signed-off-by: Mat Martineau <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

show more ...

mptcp: add net.mptcp.available_schedulers

The sysctl lists the available schedulers that can be set using
net.mptcp.scheduler similarly to net.ipv4.tcp_available_congestion_control.

Signed-off-by:

mptcp: add net.mptcp.available_schedulers

The sysctl lists the available schedulers that can be set using
net.mptcp.scheduler similarly to net.ipv4.tcp_available_congestion_control.

Signed-off-by: Gregory Detal <[email protected]>
Reviewed-by: Mat Martineau <[email protected]>
Tested-by: Geliang Tang <[email protected]>
Reviewed-by: Matthieu Baerts (NGI0) <[email protected]>
Signed-off-by: Matthieu Baerts (NGI0) <[email protected]>
Signed-off-by: Mat Martineau <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

show more ...

mptcp: only allow set existing scheduler for net.mptcp.scheduler

The current behavior is to accept any strings as inputs, this results in
an inconsistent result where an unexisting scheduler can be

mptcp: only allow set existing scheduler for net.mptcp.scheduler

The current behavior is to accept any strings as inputs, this results in
an inconsistent result where an unexisting scheduler can be set:

# sysctl -w net.mptcp.scheduler=notdefault
net.mptcp.scheduler = notdefault

This patch changes this behavior by checking for existing scheduler
before accepting the input.

Fixes: e3b2870b6d22 ("mptcp: add a new sysctl scheduler")
Cc: [email protected]
Signed-off-by: Gregory Detal <[email protected]>
Reviewed-by: Matthieu Baerts (NGI0) <[email protected]>
Tested-by: Geliang Tang <[email protected]>
Reviewed-by: Mat Martineau <[email protected]>
Signed-off-by: Matthieu Baerts (NGI0) <[email protected]>
Link: https://lore.kernel.org/r/20240506-upstream-net-20240506-mptcp-sched-exist-v1-1-2ed1529e521e@kernel.org
Signed-off-by: Jakub Kicinski <[email protected]>

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net: Remove ctl_table sentinel elements from several networking subsystems

This commit comes at the tail end of a greater effort to remove the
empty elements at the end of the ctl_table arrays (sent

net: Remove ctl_table sentinel elements from several networking subsystems

This commit comes at the tail end of a greater effort to remove the
empty elements at the end of the ctl_table arrays (sentinels) which
will reduce the overall build time size of the kernel and run time
memory bloat by ~64 bytes per sentinel (further information Link :
https://lore.kernel.org/all/ZO5Yx5JFogGi%[email protected]/)

To avoid lots of small commits, this commit brings together network
changes from (as they appear in MAINTAINERS) LLC, MPTCP, NETROM NETWORK
LAYER, PHONET PROTOCOL, ROSE NETWORK LAYER, RXRPC SOCKETS, SCTP
PROTOCOL, SHARED MEMORY COMMUNICATIONS (SMC), TIPC NETWORK LAYER and
NETWORKING [IPSEC]

* Remove sentinel element from ctl_table structs.
* Replace empty array registration with the register_net_sysctl_sz call
in llc_sysctl_init
* Replace the for loop stop condition that tests for procname == NULL
with one that depends on array size in sctp_sysctl_net_register
* Remove instances where an array element is zeroed out to make it look
like a sentinel in xfrm_sysctl_init. This is not longer needed and is
safe after commit c899710fe7f9 ("networking: Update to
register_net_sysctl_sz") added the array size to the ctl_table
registration
* Use a table_size variable to keep the value of ARRAY_SIZE

Signed-off-by: Joel Granados <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

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sysctl: treewide: constify ctl_table_header::ctl_table_arg

To be able to constify instances of struct ctl_tables it is necessary to
remove ways through which non-const versions are exposed from the

sysctl: treewide: constify ctl_table_header::ctl_table_arg

To be able to constify instances of struct ctl_tables it is necessary to
remove ways through which non-const versions are exposed from the
sysctl core.
One of these is the ctl_table_arg member of struct ctl_table_header.

Constify this reference as a prerequisite for the full constification of
struct ctl_table instances.
No functional change.

Signed-off-by: Thomas Weißschuh <[email protected]>
Reviewed-by: Kees Cook <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

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mptcp: add a new sysctl for make after break timeout

The MPTCP protocol allows sockets with no alive subflows to stay
in ESTABLISHED status for and user-defined timeout, to allow for
later subflows

mptcp: add a new sysctl for make after break timeout

The MPTCP protocol allows sockets with no alive subflows to stay
in ESTABLISHED status for and user-defined timeout, to allow for
later subflows creation.

Currently such timeout is constant - TCP_TIMEWAIT_LEN. Let the
user-space configure them via a newly added sysctl, to better cope
with busy servers and simplify (make them faster) the relevant
pktdrill tests.

Note that the new know does not apply to orphaned MPTCP socket
waiting for the data_fin handshake completion: they always wait
TCP_TIMEWAIT_LEN.

Reviewed-by: Mat Martineau <[email protected]>
Signed-off-by: Paolo Abeni <[email protected]>
Signed-off-by: Mat Martineau <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

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mptcp: add a new sysctl scheduler

This patch adds a new sysctl, named scheduler, to support for selection
of different schedulers. Export mptcp_get_scheduler helper to get this
sysctl.

Acked-by: Pa

mptcp: add a new sysctl scheduler

This patch adds a new sysctl, named scheduler, to support for selection
of different schedulers. Export mptcp_get_scheduler helper to get this
sysctl.

Acked-by: Paolo Abeni <[email protected]>
Reviewed-by: Mat Martineau <[email protected]>
Signed-off-by: Geliang Tang <[email protected]>
Signed-off-by: Mat Martineau <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

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networking: Update to register_net_sysctl_sz

Move from register_net_sysctl to register_net_sysctl_sz for all the
networking related files. Do this while making sure to mirror the NULL
assignments wi

networking: Update to register_net_sysctl_sz

Move from register_net_sysctl to register_net_sysctl_sz for all the
networking related files. Do this while making sure to mirror the NULL
assignments with a table_size of zero for the unprivileged users.

We need to move to the new function in preparation for when we change
SIZE_MAX to ARRAY_SIZE() in the register_net_sysctl macro. Failing to do
so would erroneously allow ARRAY_SIZE() to be called on a pointer. We
hold off the SIZE_MAX to ARRAY_SIZE change until we have migrated all
the relevant net sysctl registering functions to register_net_sysctl_sz
in subsequent commits.

An additional size function was added to the following files in order to
calculate the size of an array that is defined in another file:
include/net/ipv6.h
net/ipv6/icmp.c
net/ipv6/route.c
net/ipv6/sysctl_net_ipv6.c

Signed-off-by: Joel Granados <[email protected]>
Signed-off-by: Luis Chamberlain <[email protected]>

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mptcp: Add a per-namespace sysctl to set the default path manager type

The new net.mptcp.pm_type sysctl determines which path manager will be
used by each newly-created MPTCP socket.

v2: Handle bui

mptcp: Add a per-namespace sysctl to set the default path manager type

The new net.mptcp.pm_type sysctl determines which path manager will be
used by each newly-created MPTCP socket.

v2: Handle builds without CONFIG_SYSCTL
v3: Clarify logic for type-specific PM init (Geliang Tang and Paolo Abeni)

Acked-by: Paolo Abeni <[email protected]>
Signed-off-by: Mat Martineau <[email protected]>
Signed-off-by: Jakub Kicinski <[email protected]>

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mptcp: faster active backup recovery

The msk can use backup subflows to transmit in-sequence data
only if there are no other active subflow. On active backup
scenario, the MPTCP connection can do fo

mptcp: faster active backup recovery

The msk can use backup subflows to transmit in-sequence data
only if there are no other active subflow. On active backup
scenario, the MPTCP connection can do forward progress only
due to MPTCP retransmissions - rtx can pick backup subflows.

This patch introduces a new flag flow MPTCP subflows: if the
underlying TCP connection made no progresses for long time,
and there are other less problematic subflows available, the
given subflow become stale.

Stale subflows are not considered active: if all non backup
subflows become stale, the MPTCP scheduler can pick backup
subflows for plain transmissions.

Stale subflows can return in active state, as soon as any reply
from the peer is observed.

Active backup scenarios can now leverage the available b/w
with no restrinction.

Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/207
Signed-off-by: Paolo Abeni <[email protected]>
Signed-off-by: Mat Martineau <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

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mptcp: cleanup sysctl data and helpers

Reorder the data in mptcp_pernet to avoid wasting space
with no reasons and constify the access helpers.

No functional changes intended.

Signed-off-by: Paolo

mptcp: cleanup sysctl data and helpers

Reorder the data in mptcp_pernet to avoid wasting space
with no reasons and constify the access helpers.

No functional changes intended.

Signed-off-by: Paolo Abeni <[email protected]>
Signed-off-by: Mat Martineau <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

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mptcp: add sysctl allow_join_initial_addr_port

This patch added a new sysctl, named allow_join_initial_addr_port, to
control whether allow peers to send join requests to the IP address and
port numb

mptcp: add sysctl allow_join_initial_addr_port

This patch added a new sysctl, named allow_join_initial_addr_port, to
control whether allow peers to send join requests to the IP address and
port number used by the initial subflow.

Suggested-by: Florian Westphal <[email protected]>
Acked-by: Paolo Abeni <[email protected]>
Signed-off-by: Geliang Tang <[email protected]>
Signed-off-by: Mat Martineau <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

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