mirror of
git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
synced 2025-09-04 20:19:47 +08:00
ca6a6f9386
Today we have a hardcoded delay of 1 sec before a TIME-WAIT socket can be reused by reopening a connection. This is a safe choice based on an assumption that the other TCP timestamp clock frequency, which is unknown to us, may be as low as 1 Hz (RFC 7323, section 5.4). However, this means that in the presence of short lived connections with an RTT of couple of milliseconds, the time during which a 4-tuple is blocked from reuse can be orders of magnitude longer that the connection lifetime. Combined with a reduced pool of ephemeral ports, when using IP_LOCAL_PORT_RANGE to share an egress IP address between hosts [1], the long TIME-WAIT reuse delay can lead to port exhaustion, where all available 4-tuples are tied up in TIME-WAIT state. Turn the reuse delay into a per-netns setting so that sysadmins can make more aggressive assumptions about remote TCP timestamp clock frequency and shorten the delay in order to allow connections to reincarnate faster. Note that applications can completely bypass the TIME-WAIT delay protection already today by locking the local port with bind() before connecting. Such immediate connection reuse may result in PAWS failing to detect old duplicate segments, leaving us with just the sequence number check as a safety net. This new configurable offers a trade off where the sysadmin can balance between the risk of PAWS detection failing to act versus exhausting ports by having sockets tied up in TIME-WAIT state for too long. [1] https://lpc.events/event/16/contributions/1349/ Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Jason Xing <kerneljasonxing@gmail.com> Link: https://patch.msgid.link/20241209-jakub-krn-909-poc-msec-tw-tstamp-v2-2-66aca0eed03e@cloudflare.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
277 lines
7.1 KiB
C
277 lines
7.1 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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u8 sysctl_tcp_l3mdev_accept;
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/* 3 bytes hole, try to pack */
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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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int sysctl_icmp_msgs_per_sec;
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int sysctl_icmp_msgs_burst;
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atomic_t icmp_global_credit;
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u32 icmp_global_stamp;
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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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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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unsigned int sysctl_tcp_tw_reuse_delay;
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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; /* writes 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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struct hlist_head *inet_addr_lst;
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struct delayed_work addr_chk_work;
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};
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#endif
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