JIRA: https://issues.redhat.com/browse/RHEL-59087
commit 4ee2a8cace3fb9a34aea6a56426f89d26dd514f3
Author: Petr Machata <petrm@nvidia.com>
Date: Fri Jun 7 17:13:54 2024 +0200
net: ipv4: Add a sysctl to set multipath hash seed
When calculating hashes for the purpose of multipath forwarding, both IPv4
and IPv6 code currently fall back on flow_hash_from_keys(). That uses a
randomly-generated seed. That's a fine choice by default, but unfortunately
some deployments may need a tighter control over the seed used.
In this patch, make the seed configurable by adding a new sysctl key,
net.ipv4.fib_multipath_hash_seed to control the seed. This seed is used
specifically for multipath forwarding and not for the other concerns that
flow_hash_from_keys() is used for, such as queue selection. Expose the knob
as sysctl because other such settings, such as headers to hash, are also
handled that way. Like those, the multipath hash seed is a per-netns
variable.
Despite being placed in the net.ipv4 namespace, the multipath seed sysctl
is used for both IPv4 and IPv6, similarly to e.g. a number of TCP
variables.
The seed used by flow_hash_from_keys() is a 128-bit quantity. However it
seems that usually the seed is a much more modest value. 32 bits seem
typical (Cisco, Cumulus), some systems go even lower. For that reason, and
to decouple the user interface from implementation details, go with a
32-bit quantity, which is then quadruplicated to form the siphash key.
Signed-off-by: Petr Machata <petrm@nvidia.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://lore.kernel.org/r/20240607151357.421181-3-petrm@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: CKI Backport Bot <cki-ci-bot+cki-gitlab-backport-bot@redhat.com>
Signed-off-by: Ivan Vecera <ivecera@redhat.com>
JIRA: https://issues.redhat.com/browse/RHEL-11592
Conflicts:
- net/ipv4/sysctl_net_ipv4.c: context difference due to missing new sysctls
- net/ipv4/tcp_ipv4.c: context difference due to missing ccce324dabfe
("tcp: make the first N SYN RTO backoffs linear") and 37ba017dcc3b
("ipv4/tcp: do not use per netns ctl sockets")
commit b650d953cd391595e536153ce30b4aab385643ac
Author: mfreemon@cloudflare.com <mfreemon@cloudflare.com>
Date: Sun Jun 11 22:05:24 2023 -0500
tcp: enforce receive buffer memory limits by allowing the tcp window to shrink
Under certain circumstances, the tcp receive buffer memory limit
set by autotuning (sk_rcvbuf) is increased due to incoming data
packets as a result of the window not closing when it should be.
This can result in the receive buffer growing all the way up to
tcp_rmem[2], even for tcp sessions with a low BDP.
To reproduce: Connect a TCP session with the receiver doing
nothing and the sender sending small packets (an infinite loop
of socket send() with 4 bytes of payload with a sleep of 1 ms
in between each send()). This will cause the tcp receive buffer
to grow all the way up to tcp_rmem[2].
As a result, a host can have individual tcp sessions with receive
buffers of size tcp_rmem[2], and the host itself can reach tcp_mem
limits, causing the host to go into tcp memory pressure mode.
The fundamental issue is the relationship between the granularity
of the window scaling factor and the number of byte ACKed back
to the sender. This problem has previously been identified in
RFC 7323, appendix F [1].
The Linux kernel currently adheres to never shrinking the window.
In addition to the overallocation of memory mentioned above, the
current behavior is functionally incorrect, because once tcp_rmem[2]
is reached when no remediations remain (i.e. tcp collapse fails to
free up any more memory and there are no packets to prune from the
out-of-order queue), the receiver will drop in-window packets
resulting in retransmissions and an eventual timeout of the tcp
session. A receive buffer full condition should instead result
in a zero window and an indefinite wait.
In practice, this problem is largely hidden for most flows. It
is not applicable to mice flows. Elephant flows can send data
fast enough to "overrun" the sk_rcvbuf limit (in a single ACK),
triggering a zero window.
But this problem does show up for other types of flows. Examples
are websockets and other type of flows that send small amounts of
data spaced apart slightly in time. In these cases, we directly
encounter the problem described in [1].
RFC 7323, section 2.4 [2], says there are instances when a retracted
window can be offered, and that TCP implementations MUST ensure
that they handle a shrinking window, as specified in RFC 1122,
section 4.2.2.16 [3]. All prior RFCs on the topic of tcp window
management have made clear that sender must accept a shrunk window
from the receiver, including RFC 793 [4] and RFC 1323 [5].
This patch implements the functionality to shrink the tcp window
when necessary to keep the right edge within the memory limit by
autotuning (sk_rcvbuf). This new functionality is enabled with
the new sysctl: net.ipv4.tcp_shrink_window
Additional information can be found at:
https://blog.cloudflare.com/unbounded-memory-usage-by-tcp-for-receive-buffers-and-how-we-fixed-it/
[1] https://www.rfc-editor.org/rfc/rfc7323#appendix-F
[2] https://www.rfc-editor.org/rfc/rfc7323#section-2.4
[3] https://www.rfc-editor.org/rfc/rfc1122#page-91
[4] https://www.rfc-editor.org/rfc/rfc793
[5] https://www.rfc-editor.org/rfc/rfc1323
Signed-off-by: Mike Freemon <mfreemon@cloudflare.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Felix Maurer <fmaurer@redhat.com>
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2186795
Upstream Status: linux.git
commit 11052589cf5c0bab3b4884d423d5f60c38fcf25d
Author: Kuniyuki Iwashima <kuniyu@amazon.com>
Date: Wed Jul 13 10:52:07 2022 -0700
tcp/udp: Make early_demux back namespacified.
Commit e21145a987 ("ipv4: namespacify ip_early_demux sysctl knob") made
it possible to enable/disable early_demux on a per-netns basis. Then, we
introduced two knobs, tcp_early_demux and udp_early_demux, to switch it for
TCP/UDP in commit dddb64bcb3 ("net: Add sysctl to toggle early demux for
tcp and udp"). However, the .proc_handler() was wrong and actually
disabled us from changing the behaviour in each netns.
We can execute early_demux if net.ipv4.ip_early_demux is on and each proto
.early_demux() handler is not NULL. When we toggle (tcp|udp)_early_demux,
the change itself is saved in each netns variable, but the .early_demux()
handler is a global variable, so the handler is switched based on the
init_net's sysctl variable. Thus, netns (tcp|udp)_early_demux knobs have
nothing to do with the logic. Whether we CAN execute proto .early_demux()
is always decided by init_net's sysctl knob, and whether we DO it or not is
by each netns ip_early_demux knob.
This patch namespacifies (tcp|udp)_early_demux again. For now, the users
of the .early_demux() handler are TCP and UDP only, and they are called
directly to avoid retpoline. So, we can remove the .early_demux() handler
from inet6?_protos and need not dereference them in ip6?_rcv_finish_core().
If another proto needs .early_demux(), we can restore it at that time.
Fixes: dddb64bcb3 ("net: Add sysctl to toggle early demux for tcp and udp")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://lore.kernel.org/r/20220713175207.7727-1-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Guillaume Nault <gnault@redhat.com>
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2160073
Upstream Status: linux.git
commit 9b55c20f83369dd54541d9ddbe3a018a8377f451
Author: Kuniyuki Iwashima <kuniyu@amazon.com>
Date: Mon Jul 18 10:26:42 2022 -0700
ip: Fix data-races around sysctl_ip_prot_sock.
sysctl_ip_prot_sock is accessed concurrently, and there is always a chance
of data-race. So, all readers and writers need some basic protection to
avoid load/store-tearing.
Fixes: 4548b683b7 ("Introduce a sysctl that modifies the value of PROT_SOCK.")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Guillaume Nault <gnault@redhat.com>
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2149949
Upstream Status: linux.git
commit 12b8d9ca7e678abc48195294494f1815b555d658
Author: Kuniyuki Iwashima <kuniyu@amazon.com>
Date: Mon Jul 11 17:15:31 2022 -0700
tcp: Fix a data-race around sysctl_tcp_ecn_fallback.
While reading sysctl_tcp_ecn_fallback, it can be changed concurrently.
Thus, we need to add READ_ONCE() to its reader.
Fixes: 492135557d ("tcp: add rfc3168, section 6.1.1.1. fallback")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Guillaume Nault <gnault@redhat.com>
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2149949
Upstream Status: linux.git
commit 4785a66702f086cf2ea84bdbe6ec921f274bd9f2
Author: Kuniyuki Iwashima <kuniyu@amazon.com>
Date: Mon Jul 11 17:15:30 2022 -0700
tcp: Fix data-races around sysctl_tcp_ecn.
While reading sysctl_tcp_ecn, it can be changed concurrently.
Thus, we need to add READ_ONCE() to its readers.
Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Guillaume Nault <gnault@redhat.com>
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2149949
Upstream Status: linux.git
commit d2efabce81db7eed1c98fa1a3f203f0edd738ac3
Author: Kuniyuki Iwashima <kuniyu@amazon.com>
Date: Mon Jul 11 17:15:26 2022 -0700
icmp: Fix a data-race around sysctl_icmp_errors_use_inbound_ifaddr.
While reading sysctl_icmp_errors_use_inbound_ifaddr, it can be changed
concurrently. Thus, we need to add READ_ONCE() to its reader.
Fixes: 1c2fb7f93c ("[IPV4]: Sysctl configurable icmp error source address.")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Guillaume Nault <gnault@redhat.com>
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2149949
Upstream Status: linux.git
commit b04f9b7e85c7d7aecbada620e8759a662af068d3
Author: Kuniyuki Iwashima <kuniyu@amazon.com>
Date: Mon Jul 11 17:15:25 2022 -0700
icmp: Fix a data-race around sysctl_icmp_ignore_bogus_error_responses.
While reading sysctl_icmp_ignore_bogus_error_responses, it can be changed
concurrently. Thus, we need to add READ_ONCE() to its reader.
Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Guillaume Nault <gnault@redhat.com>
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2149949
Upstream Status: linux.git
commit 66484bb98ed2dfa1dda37a32411483d8311ac269
Author: Kuniyuki Iwashima <kuniyu@amazon.com>
Date: Mon Jul 11 17:15:24 2022 -0700
icmp: Fix a data-race around sysctl_icmp_echo_ignore_broadcasts.
While reading sysctl_icmp_echo_ignore_broadcasts, it can be changed
concurrently. Thus, we need to add READ_ONCE() to its reader.
Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Guillaume Nault <gnault@redhat.com>
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2149949
Upstream Status: linux.git
commit bb7bb35a63b4812da8e3aff587773678e31d23e3
Author: Kuniyuki Iwashima <kuniyu@amazon.com>
Date: Mon Jul 11 17:15:22 2022 -0700
icmp: Fix a data-race around sysctl_icmp_echo_ignore_all.
While reading sysctl_icmp_echo_ignore_all, it can be changed concurrently.
Thus, we need to add READ_ONCE() to its reader.
Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Guillaume Nault <gnault@redhat.com>
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2028420
Tested: LNST, Tier1
Upstream commit:
commit d8b81175e412c7abebdb5b37d8a84d5fd19b1aad
Author: Eric Dumazet <edumazet@google.com>
Date: Wed Sep 22 19:26:43 2021 +0200
tcp: remove sk_{tr}x_skb_cache
This reverts the following patches :
- commit 2e05fcae83 ("tcp: fix compile error if !CONFIG_SYSCTL")
- commit 4f661542a4 ("tcp: fix zerocopy and notsent_lowat issues")
- commit 472c2e07ee ("tcp: add one skb cache for tx")
- commit 8b27dae5a2 ("tcp: add one skb cache for rx")
Having a cache of one skb (in each direction) per TCP socket is fragile,
since it can cause a significant increase of memory needs,
and not good enough for high speed flows anyway where more than one skb
is needed.
We want instead to add a generic infrastructure, with more flexible
per-cpu caches, for alien NUMA nodes.
Acked-by: Paolo Abeni <pabeni@redhat.com>
Acked-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
This commit adds a new sysctl option: net.ipv4.tcp_migrate_req. If this
option is enabled or eBPF program is attached, we will be able to migrate
child sockets from a listener to another in the same reuseport group after
close() or shutdown() syscalls.
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.co.jp>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Benjamin Herrenschmidt <benh@amazon.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20210612123224.12525-2-kuniyu@amazon.co.jp
In-kernel notifications are already sent when the multipath hash policy
itself changes, but not when the multipath hash fields change.
Add these notifications, so that interested listeners (e.g., switch ASIC
drivers) could perform the necessary configuration.
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Petr Machata <petrm@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add a new multipath hash policy where the packet fields used for hash
calculation are determined by user space via the
fib_multipath_hash_fields sysctl that was introduced in the previous
patch.
The current set of available packet fields includes both outer and inner
fields, which requires two invocations of the flow dissector. Avoid
unnecessary dissection of the outer or inner flows by skipping
dissection if none of the outer or inner fields are required.
In accordance with the existing policies, when an skb is not available,
packet fields are extracted from the provided flow key. In which case,
only outer fields are considered.
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
A subsequent patch will add a new multipath hash policy where the packet
fields used for multipath hash calculation are determined by user space.
This patch adds a sysctl that allows user space to set these fields.
The packet fields are represented using a bitmask and are common between
IPv4 and IPv6 to allow user space to use the same numbering across both
protocols. For example, to hash based on standard 5-tuple:
# sysctl -w net.ipv4.fib_multipath_hash_fields=0x0037
net.ipv4.fib_multipath_hash_fields = 0x0037
The kernel rejects unknown fields, for example:
# sysctl -w net.ipv4.fib_multipath_hash_fields=0x1000
sysctl: setting key "net.ipv4.fib_multipath_hash_fields": Invalid argument
More fields can be added in the future, if needed.
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
- keep the ZC code, drop the code related to reinit
net/bridge/netfilter/ebtables.c
- fix build after move to net_generic
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Currently, tcp_allowed_congestion_control is global and writable;
writing to it in any net namespace will leak into all other net
namespaces.
tcp_available_congestion_control and tcp_allowed_congestion_control are
the only sysctls in ipv4_net_table (the per-netns sysctl table) with a
NULL data pointer; their handlers (proc_tcp_available_congestion_control
and proc_allowed_congestion_control) have no other way of referencing a
struct net. Thus, they operate globally.
Because ipv4_net_table does not use designated initializers, there is no
easy way to fix up this one "bad" table entry. However, the data pointer
updating logic shouldn't be applied to NULL pointers anyway, so we
instead force these entries to be read-only.
These sysctls used to exist in ipv4_table (init-net only), but they were
moved to the per-net ipv4_net_table, presumably without realizing that
tcp_allowed_congestion_control was writable and thus introduced a leak.
Because the intent of that commit was only to know (i.e. read) "which
congestion algorithms are available or allowed", this read-only solution
should be sufficient.
The logic added in recent commit
31c4d2f160eb: ("net: Ensure net namespace isolation of sysctls")
does not and cannot check for NULL data pointers, because
other table entries (e.g. /proc/sys/net/netfilter/nf_log/) have
.data=NULL but use other methods (.extra2) to access the struct net.
Fixes: 9cb8e048e5 ("net/ipv4/sysctl: show tcp_{allowed, available}_congestion_control in non-initial netns")
Signed-off-by: Jonathon Reinhart <jonathon.reinhart@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
sysctl_icmp_echo_enable_probe is an u8.
ipv4_net_table entry should use
.maxlen = sizeof(u8).
.proc_handler = proc_dou8vec_minmax,
Fixes: f1b8fa9fa5 ("net: add sysctl for enabling RFC 8335 PROBE messages")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Andreas Roeseler <andreas.a.roeseler@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Section 8 of RFC 8335 specifies potential security concerns of
responding to PROBE requests, and states that nodes that support PROBE
functionality MUST be able to enable/disable responses and that
responses MUST be disabled by default
Signed-off-by: Andreas Roeseler <andreas.a.roeseler@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
tcp_min_tso_segs is now stored in u8, so max value is 255.
255 limit is enforced by proc_dou8vec_minmax().
We can therefore remove the gso_max_segs variable.
Fixes: 47996b489bdc ("tcp: convert elligible sysctls to u8")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Many tcp sysctls are either bools or small ints that can fit into u8.
Reducing space taken by sysctls can save few cache line misses
when sending/receiving data while cpu caches are empty,
for example after cpu idle period.
This is hard to measure with typical network performance tests,
but after this patch, struct netns_ipv4 has shrunk
by three cache lines.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
For these sysctls, their dedicated helpers have
to use proc_dou8vec_minmax().
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This sysctl uses ip_fwd_update_priority() helper,
so the conversion needs to change it.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
These sysctls that can fit in one byte instead of one int
are converted to save space and thus reduce cache line misses.
- icmp_echo_ignore_all, icmp_echo_ignore_broadcasts,
- icmp_ignore_bogus_error_responses, icmp_errors_use_inbound_ifaddr
- tcp_ecn, tcp_ecn_fallback
- ip_default_ttl, ip_no_pmtu_disc, ip_fwd_use_pmtu
- ip_nonlocal_bind, ip_autobind_reuse
- ip_dynaddr, ip_early_demux, raw_l3mdev_accept
- nexthop_compat_mode, fwmark_reflect
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add the value '2' to 'fib_notify_on_flag_change' to allow sending
notifications only for failed route installation.
Separate value is added for such notifications because there are less of
them, so they do not impact performance and some users will find them more
important.
Signed-off-by: Amit Cohen <amcohen@nvidia.com>
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
After installing a route to the kernel, user space receives an
acknowledgment, which means the route was installed in the kernel,
but not necessarily in hardware.
The asynchronous nature of route installation in hardware can lead to a
routing daemon advertising a route before it was actually installed in
hardware. This can result in packet loss or mis-routed packets until the
route is installed in hardware.
It is also possible for a route already installed in hardware to change
its action and therefore its flags. For example, a host route that is
trapping packets can be "promoted" to perform decapsulation following
the installation of an IPinIP/VXLAN tunnel.
Emit RTM_NEWROUTE notifications whenever RTM_F_OFFLOAD/RTM_F_TRAP flags
are changed. The aim is to provide an indication to user-space
(e.g., routing daemons) about the state of the route in hardware.
Introduce a sysctl that controls this behavior.
Keep the default value at 0 (i.e., do not emit notifications) for several
reasons:
- Multiple RTM_NEWROUTE notification per-route might confuse existing
routing daemons.
- Convergence reasons in routing daemons.
- The extra notifications will negatively impact the insertion rate.
- Not all users are interested in these notifications.
Signed-off-by: Amit Cohen <amcohen@nvidia.com>
Acked-by: Roopa Prabhu <roopa@nvidia.com>
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit adds a new TCP feature to reflect the tos value received in
SYN, and send it out on the SYN-ACK, and eventually set the tos value of
the established socket with this reflected tos value. This provides a
way to set the traffic class/QoS level for all traffic in the same
connection to be the same as the incoming SYN request. It could be
useful in data centers to provide equivalent QoS according to the
incoming request.
This feature is guarded by /proc/sys/net/ipv4/tcp_reflect_tos, and is by
default turned off.
Signed-off-by: Wei Wang <weiwan@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
When TFO keys are read back on big endian systems either via the global
sysctl interface or via getsockopt() using TCP_FASTOPEN_KEY, the values
don't match what was written.
For example, on s390x:
# echo "1-2-3-4" > /proc/sys/net/ipv4/tcp_fastopen_key
# cat /proc/sys/net/ipv4/tcp_fastopen_key
02000000-01000000-04000000-03000000
Instead of:
# cat /proc/sys/net/ipv4/tcp_fastopen_key
00000001-00000002-00000003-00000004
Fix this by converting to the correct endianness on read. This was
reported by Colin Ian King when running the 'tcp_fastopen_backup_key' net
selftest on s390x, which depends on the read value matching what was
written. I've confirmed that the test now passes on big and little endian
systems.
Signed-off-by: Jason Baron <jbaron@akamai.com>
Fixes: 438ac88009 ("net: fastopen: robustness and endianness fixes for SipHash")
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Eric Dumazet <edumazet@google.com>
Reported-and-tested-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Alexei Starovoitov says:
====================
pull-request: bpf-next 2020-05-01 (v2)
The following pull-request contains BPF updates for your *net-next* tree.
We've added 61 non-merge commits during the last 6 day(s) which contain
a total of 153 files changed, 6739 insertions(+), 3367 deletions(-).
The main changes are:
1) pulled work.sysctl from vfs tree with sysctl bpf changes.
2) bpf_link observability, from Andrii.
3) BTF-defined map in map, from Andrii.
4) asan fixes for selftests, from Andrii.
5) Allow bpf_map_lookup_elem for SOCKMAP and SOCKHASH, from Jakub.
6) production cloudflare classifier as a selftes, from Lorenz.
7) bpf_ktime_get_*_ns() helper improvements, from Maciej.
8) unprivileged bpftool feature probe, from Quentin.
9) BPF_ENABLE_STATS command, from Song.
10) enable bpf_[gs]etsockopt() helpers for sock_ops progs, from Stanislav.
11) enable a bunch of common helpers for cg-device, sysctl, sockopt progs,
from Stanislav.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
Add a sysctl to control hrtimer slack, default of 100 usec.
This gives the opportunity to reduce system overhead,
and help very short RTT flows.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Soheil Hassas Yeganeh <soheil@google.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Current route nexthop API maintains user space compatibility
with old route API by default. Dumps and netlink notifications
support both new and old API format. In systems which have
moved to the new API, this compatibility mode cancels some
of the performance benefits provided by the new nexthop API.
This patch adds new sysctl nexthop_compat_mode which is on
by default but provides the ability to turn off compatibility
mode allowing systems to run entirely with the new routing
API. Old route API behaviour and support is not modified by this
sysctl.
Uses a single sysctl to cover both ipv4 and ipv6 following
other sysctls. Covers dumps and delete notifications as
suggested by David Ahern.
Signed-off-by: Roopa Prabhu <roopa@cumulusnetworks.com>
Reviewed-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Instead of having all the sysctl handlers deal with user pointers, which
is rather hairy in terms of the BPF interaction, copy the input to and
from userspace in common code. This also means that the strings are
always NUL-terminated by the common code, making the API a little bit
safer.
As most handler just pass through the data to one of the common handlers
a lot of the changes are mechnical.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Andrey Ignatov <rdna@fb.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Commit aacd9289af ("tcp: bind() use stronger
condition for bind_conflict") introduced a restriction to forbid to bind
SO_REUSEADDR enabled sockets to the same (addr, port) tuple in order to
assign ports dispersedly so that we can connect to the same remote host.
The change results in accelerating port depletion so that we fail to bind
sockets to the same local port even if we want to connect to the different
remote hosts.
You can reproduce this issue by following instructions below.
1. # sysctl -w net.ipv4.ip_local_port_range="32768 32768"
2. set SO_REUSEADDR to two sockets.
3. bind two sockets to (localhost, 0) and the latter fails.
Therefore, when ephemeral ports are exhausted, bind(0) should fallback to
the legacy behaviour to enable the SO_REUSEADDR option and make it possible
to connect to different remote (addr, port) tuples.
This patch allows us to bind SO_REUSEADDR enabled sockets to the same
(addr, port) only when net.ipv4.ip_autobind_reuse is set 1 and all
ephemeral ports are exhausted. This also allows connect() and listen() to
share ports in the following way and may break some applications. So the
ip_autobind_reuse is 0 by default and disables the feature.
1. setsockopt(sk1, SO_REUSEADDR)
2. setsockopt(sk2, SO_REUSEADDR)
3. bind(sk1, saddr, 0)
4. bind(sk2, saddr, 0)
5. connect(sk1, daddr)
6. listen(sk2)
If it is set 1, we can fully utilize the 4-tuples, but we should use
IP_BIND_ADDRESS_NO_PORT for bind()+connect() as possible.
The notable thing is that if all sockets bound to the same port have
both SO_REUSEADDR and SO_REUSEPORT enabled, we can bind sockets to an
ephemeral port and also do listen().
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.co.jp>
Signed-off-by: David S. Miller <davem@davemloft.net>
It is currenty possible to switch the TCP congestion control algorithm
in non-initial network namespaces:
unshare -U --map-root --net --fork --pid --mount-proc
echo "reno" > /proc/sys/net/ipv4/tcp_congestion_control
works just fine. But currently non-initial network namespaces have no
way of kowing which congestion algorithms are available or allowed other
than through trial and error by writing the names of the algorithms into
the aforementioned file.
Since we already allow changing the congestion algorithm in non-initial
network namespaces by exposing the tcp_congestion_control file there is
no reason to not also expose the
tcp_{allowed,available}_congestion_control files to non-initial network
namespaces. After this change a container with a separate network
namespace will show:
root@f1:~# ls -al /proc/sys/net/ipv4/tcp_* | grep congestion
-rw-r--r-- 1 root root 0 Feb 19 11:54 /proc/sys/net/ipv4/tcp_allowed_congestion_control
-r--r--r-- 1 root root 0 Feb 19 11:54 /proc/sys/net/ipv4/tcp_available_congestion_control
-rw-r--r-- 1 root root 0 Feb 19 11:54 /proc/sys/net/ipv4/tcp_congestion_control
Link: https://github.com/lxc/lxc/issues/3267
Reported-by: Haw Loeung <haw.loeung@canonical.com>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch introduces a sysctl knob "net.ipv4.tcp_no_ssthresh_metrics_save"
that disables TCP ssthresh metrics cache by default. Other parts of TCP
metrics cache, e.g. rtt, cwnd, remain unchanged.
As modern networks becoming more and more dynamic, TCP metrics cache
today often causes more harm than benefits. For example, the same IP
address is often shared by different subscribers behind NAT in residential
networks. Even if the IP address is not shared by different users,
caching the slow-start threshold of a previous short flow using loss-based
congestion control (e.g. cubic) often causes the future longer flows of
the same network path to exit slow-start prematurely with abysmal
throughput.
Caching ssthresh is very risky and can lead to terrible performance.
Therefore it makes sense to make disabling ssthresh caching by
default and opt-in for specific networks by the administrators.
This practice also has worked well for several years of deployment with
CUBIC congestion control at Google.
Acked-by: Eric Dumazet <edumazet@google.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Acked-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: Kevin(Yudong) Yang <yyd@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Minor conflict in drivers/s390/net/qeth_l2_main.c, kept the lock
from commit c8183f5489 ("s390/qeth: fix potential deadlock on
workqueue flush"), removed the code which was removed by commit
9897d583b0 ("s390/qeth: consolidate some duplicated HW cmd code").
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
snprintf returns the number of chars that would be written, not number
of chars that were actually written. As such, 'offs' may get larger than
'tbl.maxlen', causing the 'tbl.maxlen - offs' being < 0, and since the
parameter is size_t, it would overflow.
Since using scnprintf may hide the limit error, while the buffer is still
enough now, let's just add a WARN_ON_ONCE in case it reach the limit
in future.
v2: Use WARN_ON_ONCE as Jiri and Eric suggested.
Suggested-by: Jiri Benc <jbenc@redhat.com>
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Commit eec4844fae ("proc/sysctl: add shared variables for range
check") did:
- .extra2 = &two,
+ .extra2 = SYSCTL_ONE,
here, which doesn't seem to be intentional, given the changelog.
This patch restores it to the previous, as the value of 2 still makes
sense (used in fib_multipath_hash()).
Fixes: eec4844fae ("proc/sysctl: add shared variables for range check")
Cc: Matteo Croce <mcroce@redhat.com>
Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Acked-by: Matteo Croce <mcroce@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The current implementation of TCP MTU probing can considerably
underestimate the MTU on lossy connections allowing the MSS to get down to
48. We have found that in almost all of these cases on our networks these
paths can handle much larger MTUs meaning the connections are being
artificially limited. Even though TCP MTU probing can raise the MSS back up
we have seen this not to be the case causing connections to be "stuck" with
an MSS of 48 when heavy loss is present.
Prior to pushing out this change we could not keep TCP MTU probing enabled
b/c of the above reasons. Now with a reasonble floor set we've had it
enabled for the past 6 months.
The new sysctl will still default to TCP_MIN_SND_MSS (48), but gives
administrators the ability to control the floor of MSS probing.
Signed-off-by: Josh Hunt <johunt@akamai.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
In the sysctl code the proc_dointvec_minmax() function is often used to
validate the user supplied value between an allowed range. This
function uses the extra1 and extra2 members from struct ctl_table as
minimum and maximum allowed value.
On sysctl handler declaration, in every source file there are some
readonly variables containing just an integer which address is assigned
to the extra1 and extra2 members, so the sysctl range is enforced.
The special values 0, 1 and INT_MAX are very often used as range
boundary, leading duplication of variables like zero=0, one=1,
int_max=INT_MAX in different source files:
$ git grep -E '\.extra[12].*&(zero|one|int_max)' |wc -l
248
Add a const int array containing the most commonly used values, some
macros to refer more easily to the correct array member, and use them
instead of creating a local one for every object file.
This is the bloat-o-meter output comparing the old and new binary
compiled with the default Fedora config:
# scripts/bloat-o-meter -d vmlinux.o.old vmlinux.o
add/remove: 2/2 grow/shrink: 0/2 up/down: 24/-188 (-164)
Data old new delta
sysctl_vals - 12 +12
__kstrtab_sysctl_vals - 12 +12
max 14 10 -4
int_max 16 - -16
one 68 - -68
zero 128 28 -100
Total: Before=20583249, After=20583085, chg -0.00%
[mcroce@redhat.com: tipc: remove two unused variables]
Link: http://lkml.kernel.org/r/20190530091952.4108-1-mcroce@redhat.com
[akpm@linux-foundation.org: fix net/ipv6/sysctl_net_ipv6.c]
[arnd@arndb.de: proc/sysctl: make firmware loader table conditional]
Link: http://lkml.kernel.org/r/20190617130014.1713870-1-arnd@arndb.de
[akpm@linux-foundation.org: fix fs/eventpoll.c]
Link: http://lkml.kernel.org/r/20190430180111.10688-1-mcroce@redhat.com
Signed-off-by: Matteo Croce <mcroce@redhat.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Aaron Tomlin <atomlin@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Some changes to the TCP fastopen code to make it more robust
against future changes in the choice of key/cookie size, etc.
- Instead of keeping the SipHash key in an untyped u8[] buffer
and casting it to the right type upon use, use the correct
type directly. This ensures that the key will appear at the
correct alignment if we ever change the way these data
structures are allocated. (Currently, they are only allocated
via kmalloc so they always appear at the correct alignment)
- Use DIV_ROUND_UP when sizing the u64[] array to hold the
cookie, so it is always of sufficient size, even if
TCP_FASTOPEN_COOKIE_MAX is no longer a multiple of 8.
- Drop the 'len' parameter from the tcp_fastopen_reset_cipher()
function, which is no longer used.
- Add endian swabbing when setting the keys and calculating the hash,
to ensure that cookie values are the same for a given key and
source/destination address pair regardless of the endianness of
the server.
Note that none of these are functional changes wrt the current
state of the code, with the exception of the swabbing, which only
affects big endian systems.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Eric Dumazet says:
====================
tcp: make sack processing more robust
Jonathan Looney brought to our attention multiple problems
in TCP stack at the sender side.
SACK processing can be abused by malicious peers to either
cause overflows, or increase of memory usage.
First two patches fix the immediate problems.
Since the malicious peers abuse senders by advertizing a very
small MSS in their SYN or SYNACK packet, the last two
patches add a new sysctl so that admins can chose a higher
limit for MSS clamping.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
tcp_tx_skb_cache_key and tcp_rx_skb_cache_key must be available
even if CONFIG_SYSCTL is not set.
Fixes: 0b7d7f6b22 ("tcp: add tcp_tx_skb_cache sysctl")
Fixes: ede61ca474 ("tcp: add tcp_rx_skb_cache sysctl")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Ivan Vecera
Felix Maurer
Guillaume Nault
Paolo Abeni
Kuniyuki Iwashima
Ido Schimmel
Ido Schimmel
Jakub Kicinski
Jonathon Reinhart
Eric Dumazet
Andreas Roeseler
Amit Cohen
Wei Wang
Jason Baron
David S. Miller
Roopa Prabhu
Christoph Hellwig
Christian Brauner
Kevin(Yudong) Yang
Jakub Kicinski
Hangbin Liu
Marcelo Ricardo Leitner
Josh Hunt
Matteo Croce
Ard Biesheuvel