4ee2a8cace
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>
272 lines
6.9 KiB
C
272 lines
6.9 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* ipv4 in net namespaces
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*/
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#ifndef __NETNS_IPV4_H__
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#define __NETNS_IPV4_H__
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#include <linux/uidgid.h>
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#include <net/inet_frag.h>
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#include <linux/rcupdate.h>
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#include <linux/seqlock.h>
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#include <linux/siphash.h>
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struct ctl_table_header;
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struct ipv4_devconf;
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struct fib_rules_ops;
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struct hlist_head;
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struct fib_table;
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struct sock;
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struct local_ports {
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u32 range; /* high << 16 | low */
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bool warned;
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};
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struct ping_group_range {
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seqlock_t lock;
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kgid_t range[2];
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};
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struct inet_hashinfo;
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struct inet_timewait_death_row {
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refcount_t tw_refcount;
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/* Padding to avoid false sharing, tw_refcount can be often written */
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struct inet_hashinfo *hashinfo ____cacheline_aligned_in_smp;
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int sysctl_max_tw_buckets;
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};
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struct tcp_fastopen_context;
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#ifdef CONFIG_IP_ROUTE_MULTIPATH
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struct sysctl_fib_multipath_hash_seed {
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u32 user_seed;
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u32 mp_seed;
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};
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#endif
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struct netns_ipv4 {
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/* Cacheline organization can be found documented in
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* Documentation/networking/net_cachelines/netns_ipv4_sysctl.rst.
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* Please update the document when adding new fields.
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*/
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/* TX readonly hotpath cache lines */
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__cacheline_group_begin(netns_ipv4_read_tx);
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u8 sysctl_tcp_early_retrans;
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u8 sysctl_tcp_tso_win_divisor;
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u8 sysctl_tcp_tso_rtt_log;
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u8 sysctl_tcp_autocorking;
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int sysctl_tcp_min_snd_mss;
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unsigned int sysctl_tcp_notsent_lowat;
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int sysctl_tcp_limit_output_bytes;
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int sysctl_tcp_min_rtt_wlen;
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int sysctl_tcp_wmem[3];
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u8 sysctl_ip_fwd_use_pmtu;
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__cacheline_group_end(netns_ipv4_read_tx);
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/* TXRX readonly hotpath cache lines */
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__cacheline_group_begin(netns_ipv4_read_txrx);
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u8 sysctl_tcp_moderate_rcvbuf;
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__cacheline_group_end(netns_ipv4_read_txrx);
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/* RX readonly hotpath cache line */
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__cacheline_group_begin(netns_ipv4_read_rx);
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u8 sysctl_ip_early_demux;
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u8 sysctl_tcp_early_demux;
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int sysctl_tcp_reordering;
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int sysctl_tcp_rmem[3];
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__cacheline_group_end(netns_ipv4_read_rx);
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struct inet_timewait_death_row tcp_death_row;
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struct udp_table *udp_table;
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#ifdef CONFIG_SYSCTL
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struct ctl_table_header *forw_hdr;
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struct ctl_table_header *frags_hdr;
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struct ctl_table_header *ipv4_hdr;
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struct ctl_table_header *route_hdr;
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struct ctl_table_header *xfrm4_hdr;
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#endif
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struct ipv4_devconf *devconf_all;
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struct ipv4_devconf *devconf_dflt;
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struct ip_ra_chain __rcu *ra_chain;
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struct mutex ra_mutex;
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#ifdef CONFIG_IP_MULTIPLE_TABLES
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struct fib_rules_ops *rules_ops;
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struct fib_table __rcu *fib_main;
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struct fib_table __rcu *fib_default;
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unsigned int fib_rules_require_fldissect;
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bool fib_has_custom_rules;
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#endif
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bool fib_has_custom_local_routes;
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bool fib_offload_disabled;
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u8 sysctl_tcp_shrink_window;
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#ifdef CONFIG_IP_ROUTE_CLASSID
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atomic_t fib_num_tclassid_users;
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#endif
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struct hlist_head *fib_table_hash;
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struct sock *fibnl;
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struct sock *mc_autojoin_sk;
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struct inet_peer_base *peers;
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struct fqdir *fqdir;
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u8 sysctl_icmp_echo_ignore_all;
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u8 sysctl_icmp_echo_enable_probe;
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u8 sysctl_icmp_echo_ignore_broadcasts;
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u8 sysctl_icmp_ignore_bogus_error_responses;
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u8 sysctl_icmp_errors_use_inbound_ifaddr;
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int sysctl_icmp_ratelimit;
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int sysctl_icmp_ratemask;
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u32 ip_rt_min_pmtu;
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int ip_rt_mtu_expires;
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int ip_rt_min_advmss;
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struct local_ports ip_local_ports;
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u8 sysctl_tcp_ecn;
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u8 sysctl_tcp_ecn_fallback;
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u8 sysctl_ip_default_ttl;
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u8 sysctl_ip_no_pmtu_disc;
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u8 sysctl_ip_fwd_update_priority;
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u8 sysctl_ip_nonlocal_bind;
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u8 sysctl_ip_autobind_reuse;
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/* Shall we try to damage output packets if routing dev changes? */
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u8 sysctl_ip_dynaddr;
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#ifdef CONFIG_NET_L3_MASTER_DEV
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u8 sysctl_raw_l3mdev_accept;
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#endif
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u8 sysctl_udp_early_demux;
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u8 sysctl_nexthop_compat_mode;
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u8 sysctl_fwmark_reflect;
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u8 sysctl_tcp_fwmark_accept;
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#ifdef CONFIG_NET_L3_MASTER_DEV
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u8 sysctl_tcp_l3mdev_accept;
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#endif
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u8 sysctl_tcp_mtu_probing;
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int sysctl_tcp_mtu_probe_floor;
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int sysctl_tcp_base_mss;
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int sysctl_tcp_probe_threshold;
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u32 sysctl_tcp_probe_interval;
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int sysctl_tcp_keepalive_time;
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int sysctl_tcp_keepalive_intvl;
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u8 sysctl_tcp_keepalive_probes;
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u8 sysctl_tcp_syn_retries;
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u8 sysctl_tcp_synack_retries;
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u8 sysctl_tcp_syncookies;
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u8 sysctl_tcp_migrate_req;
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u8 sysctl_tcp_comp_sack_nr;
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u8 sysctl_tcp_backlog_ack_defer;
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u8 sysctl_tcp_pingpong_thresh;
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u8 sysctl_tcp_retries1;
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u8 sysctl_tcp_retries2;
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u8 sysctl_tcp_orphan_retries;
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u8 sysctl_tcp_tw_reuse;
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int sysctl_tcp_fin_timeout;
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u8 sysctl_tcp_sack;
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u8 sysctl_tcp_window_scaling;
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u8 sysctl_tcp_timestamps;
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int sysctl_tcp_rto_min_us;
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u8 sysctl_tcp_recovery;
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u8 sysctl_tcp_thin_linear_timeouts;
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u8 sysctl_tcp_slow_start_after_idle;
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u8 sysctl_tcp_retrans_collapse;
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u8 sysctl_tcp_stdurg;
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u8 sysctl_tcp_rfc1337;
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u8 sysctl_tcp_abort_on_overflow;
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u8 sysctl_tcp_fack; /* obsolete */
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int sysctl_tcp_max_reordering;
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int sysctl_tcp_adv_win_scale; /* obsolete */
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u8 sysctl_tcp_dsack;
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u8 sysctl_tcp_app_win;
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u8 sysctl_tcp_frto;
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u8 sysctl_tcp_nometrics_save;
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u8 sysctl_tcp_no_ssthresh_metrics_save;
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u8 sysctl_tcp_workaround_signed_windows;
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int sysctl_tcp_challenge_ack_limit;
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u8 sysctl_tcp_min_tso_segs;
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u8 sysctl_tcp_reflect_tos;
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int sysctl_tcp_invalid_ratelimit;
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int sysctl_tcp_pacing_ss_ratio;
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int sysctl_tcp_pacing_ca_ratio;
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unsigned int sysctl_tcp_child_ehash_entries;
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unsigned long sysctl_tcp_comp_sack_delay_ns;
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unsigned long sysctl_tcp_comp_sack_slack_ns;
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int sysctl_max_syn_backlog;
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int sysctl_tcp_fastopen;
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const struct tcp_congestion_ops __rcu *tcp_congestion_control;
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struct tcp_fastopen_context __rcu *tcp_fastopen_ctx;
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unsigned int sysctl_tcp_fastopen_blackhole_timeout;
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atomic_t tfo_active_disable_times;
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unsigned long tfo_active_disable_stamp;
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u32 tcp_challenge_timestamp;
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u32 tcp_challenge_count;
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u8 sysctl_tcp_plb_enabled;
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u8 sysctl_tcp_plb_idle_rehash_rounds;
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u8 sysctl_tcp_plb_rehash_rounds;
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u8 sysctl_tcp_plb_suspend_rto_sec;
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int sysctl_tcp_plb_cong_thresh;
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int sysctl_udp_wmem_min;
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int sysctl_udp_rmem_min;
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u8 sysctl_fib_notify_on_flag_change;
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u8 sysctl_tcp_syn_linear_timeouts;
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#ifdef CONFIG_NET_L3_MASTER_DEV
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u8 sysctl_udp_l3mdev_accept;
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#endif
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u8 sysctl_igmp_llm_reports;
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int sysctl_igmp_max_memberships;
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int sysctl_igmp_max_msf;
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int sysctl_igmp_qrv;
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struct ping_group_range ping_group_range;
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atomic_t dev_addr_genid;
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unsigned int sysctl_udp_child_hash_entries;
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#ifdef CONFIG_SYSCTL
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unsigned long *sysctl_local_reserved_ports;
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int sysctl_ip_prot_sock;
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#endif
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#ifdef CONFIG_IP_MROUTE
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#ifndef CONFIG_IP_MROUTE_MULTIPLE_TABLES
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struct mr_table *mrt;
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#else
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struct list_head mr_tables;
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struct fib_rules_ops *mr_rules_ops;
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#endif
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#endif
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#ifdef CONFIG_IP_ROUTE_MULTIPATH
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struct sysctl_fib_multipath_hash_seed sysctl_fib_multipath_hash_seed;
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u32 sysctl_fib_multipath_hash_fields;
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u8 sysctl_fib_multipath_use_neigh;
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u8 sysctl_fib_multipath_hash_policy;
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#endif
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struct fib_notifier_ops *notifier_ops;
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unsigned int fib_seq; /* protected by rtnl_mutex */
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struct fib_notifier_ops *ipmr_notifier_ops;
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unsigned int ipmr_seq; /* protected by rtnl_mutex */
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atomic_t rt_genid;
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siphash_key_t ip_id_key;
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};
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#endif
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