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path: root/net/ipv4/sysctl_net_ipv4.c
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2021-09-23tcp: remove sk_{tr}x_skb_cacheEric Dumazet
This reverts the following patches : - commit 2e05fcae83c4 ("tcp: fix compile error if !CONFIG_SYSCTL") - commit 4f661542a402 ("tcp: fix zerocopy and notsent_lowat issues") - commit 472c2e07eef0 ("tcp: add one skb cache for tx") - commit 8b27dae5a2e8 ("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>
2021-09-21net/ipv4/sysctl_net_ipv4.c: remove superfluous header files from ↵Mianhan Liu
sysctl_net_ipv4.c sysctl_net_ipv4.c hasn't use any macro or function declared in igmp.h, inetdevice.h, mm.h, module.h, nsproxy.h, swap.h, inet_frag.h, route.h and snmp.h. Thus, these files can be removed from sysctl_net_ipv4.c safely without affecting the compilation of the net module. Signed-off-by: Mianhan Liu <liumh1@shanghaitech.edu.cn> Signed-off-by: David S. Miller <davem@davemloft.net>
2021-06-15net: Introduce net.ipv4.tcp_migrate_req.Kuniyuki Iwashima
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
2021-05-19net: Add notifications when multipath hash field changeIdo Schimmel
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>
2021-05-18ipv4: Add custom multipath hash policyIdo Schimmel
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>
2021-05-18ipv4: Add a sysctl to control multipath hash fieldsIdo Schimmel
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>
2021-04-17Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski
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>
2021-04-13net: Make tcp_allowed_congestion_control readonly in non-init netnsJonathon Reinhart
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: 9cb8e048e5d9 ("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>
2021-03-31tcp: convert tcp_comp_sack_nr sysctl to u8Eric Dumazet
tcp_comp_sack_nr max value was already 255. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2021-03-31ipv4: convert igmp_link_local_mcast_reports sysctl to u8Eric Dumazet
This sysctl is a bool, can use less storage. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2021-03-31ipv4: convert fib_multipath_{use_neigh|hash_policy} sysctls to u8Eric Dumazet
Make room for better packing of netns_ipv4 Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2021-03-31ipv4: convert udp_l3mdev_accept sysctl to u8Eric Dumazet
Reduce footprint of sysctls. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2021-03-31ipv4: convert fib_notify_on_flag_change sysctl to u8Eric Dumazet
Reduce footprint of sysctls. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2021-03-30net: fix icmp_echo_enable_probe sysctlEric Dumazet
sysctl_icmp_echo_enable_probe is an u8. ipv4_net_table entry should use .maxlen = sizeof(u8). .proc_handler = proc_dou8vec_minmax, Fixes: f1b8fa9fa586 ("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>
2021-03-30net: add sysctl for enabling RFC 8335 PROBE messagesAndreas Roeseler
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>
2021-03-29tcp: fix tcp_min_tso_segs sysctlEric Dumazet
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>
2021-03-25tcp: convert elligible sysctls to u8Eric Dumazet
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>
2021-03-25inet: convert tcp_early_demux and udp_early_demux to u8Eric Dumazet
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>
2021-03-25ipv4: convert ip_forward_update_priority sysctl to u8Eric Dumazet
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>
2021-03-25ipv4: shrink netns_ipv4 with sysctl conversionsEric Dumazet
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>
2021-02-08IPv4: Extend 'fib_notify_on_flag_change' sysctlAmit Cohen
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>
2021-02-02net: ipv4: Emit notification when fib hardware flags are changedAmit Cohen
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>
2020-09-10tcp: reflect tos value received in SYN to the socketWei Wang
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>
2020-08-10tcp: correct read of TFO keys on big endian systemsJason Baron
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: 438ac88009bc ("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>
2020-05-01Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-nextDavid S. Miller
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>
2020-04-30tcp: add hrtimer slack to sack compressionEric Dumazet
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>
2020-04-28net: ipv4: add sysctl for nexthop api compatibility modeRoopa Prabhu
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>
2020-04-27sysctl: pass kernel pointers to ->proc_handlerChristoph Hellwig
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>
2020-03-12tcp: bind(0) remove the SO_REUSEADDR restriction when ephemeral ports are ↵Kuniyuki Iwashima
exhausted. Commit aacd9289af8b82f5fb01bcdd53d0e3406d1333c7 ("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>
2020-02-19net/ipv4/sysctl: show tcp_{allowed, available}_congestion_control in ↵Christian Brauner
non-initial netns 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>
2019-12-09net-tcp: Disable TCP ssthresh metrics cache by defaultKevin(Yudong) Yang
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>
2019-11-22Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski
Minor conflict in drivers/s390/net/qeth_l2_main.c, kept the lock from commit c8183f548902 ("s390/qeth: fix potential deadlock on workqueue flush"), removed the code which was removed by commit 9897d583b015 ("s390/qeth: consolidate some duplicated HW cmd code"). Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
2019-11-20tcp: warn if offset reach the maxlen limit when using snprintfHangbin Liu
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>
2019-11-18net/ipv4: fix sysctl max for fib_multipath_hash_policyMarcelo Ricardo Leitner
Commit eec4844fae7c ("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: eec4844fae7c ("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>
2019-08-09tcp: add new tcp_mtu_probe_floor sysctlJosh Hunt
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>
2019-07-18proc/sysctl: add shared variables for range checkMatteo Croce
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>
2019-06-22net: fastopen: robustness and endianness fixes for SipHashArd Biesheuvel
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>
2019-06-17Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netDavid S. Miller
Honestly all the conflicts were simple overlapping changes, nothing really interesting to report. Signed-off-by: David S. Miller <davem@davemloft.net>
2019-06-17Merge branch 'tcp-fixes'David S. Miller
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>
2019-06-16tcp: fix compile error if !CONFIG_SYSCTLEric Dumazet
tcp_tx_skb_cache_key and tcp_rx_skb_cache_key must be available even if CONFIG_SYSCTL is not set. Fixes: 0b7d7f6b2208 ("tcp: add tcp_tx_skb_cache sysctl") Fixes: ede61ca474a0 ("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>
2019-06-15tcp: add tcp_min_snd_mss sysctlEric Dumazet
Some TCP peers announce a very small MSS option in their SYN and/or SYN/ACK messages. This forces the stack to send packets with a very high network/cpu overhead. Linux has enforced a minimal value of 48. Since this value includes the size of TCP options, and that the options can consume up to 40 bytes, this means that each segment can include only 8 bytes of payload. In some cases, it can be useful to increase the minimal value to a saner value. We still let the default to 48 (TCP_MIN_SND_MSS), for compatibility reasons. Note that TCP_MAXSEG socket option enforces a minimal value of (TCP_MIN_MSS). David Miller increased this minimal value in commit c39508d6f118 ("tcp: Make TCP_MAXSEG minimum more correct.") from 64 to 88. We might in the future merge TCP_MIN_SND_MSS and TCP_MIN_MSS. CVE-2019-11479 -- tcp mss hardcoded to 48 Signed-off-by: Eric Dumazet <edumazet@google.com> Suggested-by: Jonathan Looney <jtl@netflix.com> Acked-by: Neal Cardwell <ncardwell@google.com> Cc: Yuchung Cheng <ycheng@google.com> Cc: Tyler Hicks <tyhicks@canonical.com> Cc: Bruce Curtis <brucec@netflix.com> Cc: Jonathan Lemon <jonathan.lemon@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-06-14tcp: add tcp_tx_skb_cache sysctlEric Dumazet
Feng Tang reported a performance regression after introduction of per TCP socket tx/rx caches, for TCP over loopback (netperf) There is high chance the regression is caused by a change on how well the 32 KB per-thread page (current->task_frag) can be recycled, and lack of pcp caches for order-3 pages. I could not reproduce the regression myself, cpus all being spinning on the mm spinlocks for page allocs/freeing, regardless of enabling or disabling the per tcp socket caches. It seems best to disable the feature by default, and let admins enabling it. MM layer either needs to provide scalable order-3 pages allocations, or could attempt a trylock on zone->lock if the caller only attempts to get a high-order page and is able to fallback to order-0 ones in case of pressure. Tests run on a 56 cores host (112 hyper threads) - 35.49% netperf [kernel.vmlinux] [k] queued_spin_lock_slowpath - 35.49% queued_spin_lock_slowpath - 18.18% get_page_from_freelist - __alloc_pages_nodemask - 18.18% alloc_pages_current skb_page_frag_refill sk_page_frag_refill tcp_sendmsg_locked tcp_sendmsg inet_sendmsg sock_sendmsg __sys_sendto __x64_sys_sendto do_syscall_64 entry_SYSCALL_64_after_hwframe __libc_send + 17.31% __free_pages_ok + 31.43% swapper [kernel.vmlinux] [k] intel_idle + 9.12% netperf [kernel.vmlinux] [k] copy_user_enhanced_fast_string + 6.53% netserver [kernel.vmlinux] [k] copy_user_enhanced_fast_string + 0.69% netserver [kernel.vmlinux] [k] queued_spin_lock_slowpath + 0.68% netperf [kernel.vmlinux] [k] skb_release_data + 0.52% netperf [kernel.vmlinux] [k] tcp_sendmsg_locked 0.46% netperf [kernel.vmlinux] [k] _raw_spin_lock_irqsave Fixes: 472c2e07eef0 ("tcp: add one skb cache for tx") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: Feng Tang <feng.tang@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-06-14tcp: add tcp_rx_skb_cache sysctlEric Dumazet
Instead of relying on rps_needed, it is safer to use a separate static key, since we do not want to enable TCP rx_skb_cache by default. This feature can cause huge increase of memory usage on hosts with millions of sockets. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-06-14ipv4: Support multipath hashing on inner IP pkts for GRE tunnelStephen Suryaputra
Multipath hash policy value of 0 isn't distributing since the outer IP dest and src aren't varied eventhough the inner ones are. Since the flow is on the inner ones in the case of tunneled traffic, hashing on them is desired. This is done mainly for IP over GRE, hence only tested for that. But anything else supported by flow dissection should work. v2: Use skb_flow_dissect_flow_keys() directly so that other tunneling can be supported through flow dissection (per Nikolay Aleksandrov). v3: Remove accidental inclusion of ports in the hash keys and clarify the documentation (Nikolay Alexandrov). Signed-off-by: Stephen Suryaputra <ssuryaextr@gmail.com> Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-05-30tcp: add support for optional TFO backup key to net.ipv4.tcp_fastopen_keyJason Baron
Add the ability to add a backup TFO key as: # echo "x-x-x-x,x-x-x-x" > /proc/sys/net/ipv4/tcp_fastopen_key The key before the comma acks as the primary TFO key and the key after the comma is the backup TFO key. This change is intended to be backwards compatible since if only one key is set, userspace will simply read back that single key as follows: # echo "x-x-x-x" > /proc/sys/net/ipv4/tcp_fastopen_key # cat /proc/sys/net/ipv4/tcp_fastopen_key x-x-x-x Signed-off-by: Jason Baron <jbaron@akamai.com> Signed-off-by: Christoph Paasch <cpaasch@apple.com> Acked-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-05-30tcp: add backup TFO key infrastructureJason Baron
We would like to be able to rotate TFO keys while minimizing the number of client cookies that are rejected. Currently, we have only one key which can be used to generate and validate cookies, thus if we simply replace this key clients can easily have cookies rejected upon rotation. We propose having the ability to have both a primary key and a backup key. The primary key is used to generate as well as to validate cookies. The backup is only used to validate cookies. Thus, keys can be rotated as: 1) generate new key 2) add new key as the backup key 3) swap the primary and backup key, thus setting the new key as the primary We don't simply set the new key as the primary key and move the old key to the backup slot because the ip may be behind a load balancer and we further allow for the fact that all machines behind the load balancer will not be updated simultaneously. We make use of this infrastructure in subsequent patches. Suggested-by: Igor Lubashev <ilubashe@akamai.com> Signed-off-by: Jason Baron <jbaron@akamai.com> Signed-off-by: Christoph Paasch <cpaasch@apple.com> Acked-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-04-25Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netDavid S. Miller
Two easy cases of overlapping changes. Signed-off-by: David S. Miller <davem@davemloft.net>
2019-04-17ipv4: set the tcp_min_rtt_wlen range from 0 to one dayZhangXiaoxu
There is a UBSAN report as below: UBSAN: Undefined behaviour in net/ipv4/tcp_input.c:2877:56 signed integer overflow: 2147483647 * 1000 cannot be represented in type 'int' CPU: 3 PID: 0 Comm: swapper/3 Not tainted 5.1.0-rc4-00058-g582549e #1 Call Trace: <IRQ> dump_stack+0x8c/0xba ubsan_epilogue+0x11/0x60 handle_overflow+0x12d/0x170 ? ttwu_do_wakeup+0x21/0x320 __ubsan_handle_mul_overflow+0x12/0x20 tcp_ack_update_rtt+0x76c/0x780 tcp_clean_rtx_queue+0x499/0x14d0 tcp_ack+0x69e/0x1240 ? __wake_up_sync_key+0x2c/0x50 ? update_group_capacity+0x50/0x680 tcp_rcv_established+0x4e2/0xe10 tcp_v4_do_rcv+0x22b/0x420 tcp_v4_rcv+0xfe8/0x1190 ip_protocol_deliver_rcu+0x36/0x180 ip_local_deliver+0x15b/0x1a0 ip_rcv+0xac/0xd0 __netif_receive_skb_one_core+0x7f/0xb0 __netif_receive_skb+0x33/0xc0 netif_receive_skb_internal+0x84/0x1c0 napi_gro_receive+0x2a0/0x300 receive_buf+0x3d4/0x2350 ? detach_buf_split+0x159/0x390 virtnet_poll+0x198/0x840 ? reweight_entity+0x243/0x4b0 net_rx_action+0x25c/0x770 __do_softirq+0x19b/0x66d irq_exit+0x1eb/0x230 do_IRQ+0x7a/0x150 common_interrupt+0xf/0xf </IRQ> It can be reproduced by: echo 2147483647 > /proc/sys/net/ipv4/tcp_min_rtt_wlen Fixes: f672258391b42 ("tcp: track min RTT using windowed min-filter") Signed-off-by: ZhangXiaoxu <zhangxiaoxu5@huawei.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-03-21ipv4: Allow amount of dirty memory from fib resizing to be controllableDavid Ahern
fib_trie implementation calls synchronize_rcu when a certain amount of pages are dirty from freed entries. The number of pages was determined experimentally in 2009 (commit c3059477fce2d). At the current setting, synchronize_rcu is called often -- 51 times in a second in one test with an average of an 8 msec delay adding a fib entry. The total impact is a lot of slow down modifying the fib. This is seen in the output of 'time' - the difference between real time and sys+user. For example, using 720,022 single path routes and 'ip -batch'[1]: $ time ./ip -batch ipv4/routes-1-hops real 0m14.214s user 0m2.513s sys 0m6.783s So roughly 35% of the actual time to install the routes is from the ip command getting scheduled out, most notably due to synchronize_rcu (this is observed using 'perf sched timehist'). This patch makes the amount of dirty memory configurable between 64k where the synchronize_rcu is called often (small, low end systems that are memory sensitive) to 64M where synchronize_rcu is called rarely during a large FIB change (for high end systems with lots of memory). The default is 512kB which corresponds to the current setting of 128 pages with a 4kB page size. As an example, at 16MB the worst interval shows 4 calls to synchronize_rcu in a second blocking for up to 30 msec in a single instance, and a total of almost 100 msec across the 4 calls in the second. The trade off is allowing FIB entries to consume more memory in a given time window but but with much better fib insertion rates (~30% increase in prefixes/sec). With this patch and net.ipv4.fib_sync_mem set to 16MB, the same batch file runs in: $ time ./ip -batch ipv4/routes-1-hops real 0m9.692s user 0m2.491s sys 0m6.769s So the dead time is reduced to about 1/2 second or <5% of the real time. [1] 'ip' modified to not request ACK messages which improves route insertion times by about 20% Signed-off-by: David Ahern <dsahern@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-11-07net: provide a sysctl raw_l3mdev_accept for raw socket lookup with VRFsMike Manning
Add a sysctl raw_l3mdev_accept to control raw socket lookup in a manner similar to use of tcp_l3mdev_accept for stream and of udp_l3mdev_accept for datagram sockets. Have this default to enabled for reasons of backwards compatibility. This is so as to specify the output device with cmsg and IP_PKTINFO, but using a socket not bound to the corresponding VRF. This allows e.g. older ping implementations to be run with specifying the device but without executing it in the VRF. If the option is disabled, packets received in a VRF context are only handled by a raw socket bound to the VRF, and correspondingly packets in the default VRF are only handled by a socket not bound to any VRF. Signed-off-by: Mike Manning <mmanning@vyatta.att-mail.com> Reviewed-by: David Ahern <dsahern@gmail.com> Tested-by: David Ahern <dsahern@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
generated by cgit (git 2.34.1) at 2024-06-12 06:09:21 +0000