mirror of
https://mirrors.bfsu.edu.cn/git/linux.git
synced 2024-12-05 01:54:09 +08:00
614e8316aa
Back in 2015, Van Jacobson suggested to use usec resolution in TCP TS values. This has been implemented in our private kernels. Goals were : 1) better observability of delays in networking stacks. 2) better disambiguation of events based on TSval/ecr values. 3) building block for congestion control modules needing usec resolution. Back then we implemented a schem based on private SYN options to negotiate the feature. For upstream submission, we chose to use a route attribute, because this feature is probably going to be used in private networks [1] [2]. ip route add 10/8 ... features tcp_usec_ts Note that RFC 7323 recommends a "timestamp clock frequency in the range 1 ms to 1 sec per tick.", but also mentions "the maximum acceptable clock frequency is one tick every 59 ns." [1] Unfortunately RFC 7323 5.5 (Outdated Timestamps) suggests to invalidate TS.Recent values after a flow was idle for more than 24 days. This is the part making usec_ts a problem for peers following this recommendation for long living idle flows. [2] Attempts to standardize usec ts went nowhere: https://www.ietf.org/proceedings/97/slides/slides-97-tcpm-tcp-options-for-low-latency-00.pdf https://datatracker.ietf.org/doc/draft-wang-tcpm-low-latency-opt/ Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
132 lines
3.8 KiB
C
132 lines
3.8 KiB
C
/* SPDX-License-Identifier: GPL-2.0-or-later */
|
|
/*
|
|
* INET An implementation of the TCP/IP protocol suite for the LINUX
|
|
* operating system. INET is implemented using the BSD Socket
|
|
* interface as the means of communication with the user level.
|
|
*
|
|
* Definitions for a generic INET TIMEWAIT sock
|
|
*
|
|
* From code originally in net/tcp.h
|
|
*/
|
|
#ifndef _INET_TIMEWAIT_SOCK_
|
|
#define _INET_TIMEWAIT_SOCK_
|
|
|
|
#include <linux/list.h>
|
|
#include <linux/timer.h>
|
|
#include <linux/types.h>
|
|
#include <linux/workqueue.h>
|
|
|
|
#include <net/inet_sock.h>
|
|
#include <net/sock.h>
|
|
#include <net/tcp_states.h>
|
|
#include <net/timewait_sock.h>
|
|
|
|
#include <linux/atomic.h>
|
|
|
|
struct inet_bind_bucket;
|
|
|
|
/*
|
|
* This is a TIME_WAIT sock. It works around the memory consumption
|
|
* problems of sockets in such a state on heavily loaded servers, but
|
|
* without violating the protocol specification.
|
|
*/
|
|
struct inet_timewait_sock {
|
|
/*
|
|
* Now struct sock also uses sock_common, so please just
|
|
* don't add nothing before this first member (__tw_common) --acme
|
|
*/
|
|
struct sock_common __tw_common;
|
|
#define tw_family __tw_common.skc_family
|
|
#define tw_state __tw_common.skc_state
|
|
#define tw_reuse __tw_common.skc_reuse
|
|
#define tw_reuseport __tw_common.skc_reuseport
|
|
#define tw_ipv6only __tw_common.skc_ipv6only
|
|
#define tw_bound_dev_if __tw_common.skc_bound_dev_if
|
|
#define tw_node __tw_common.skc_nulls_node
|
|
#define tw_bind_node __tw_common.skc_bind_node
|
|
#define tw_refcnt __tw_common.skc_refcnt
|
|
#define tw_hash __tw_common.skc_hash
|
|
#define tw_prot __tw_common.skc_prot
|
|
#define tw_net __tw_common.skc_net
|
|
#define tw_daddr __tw_common.skc_daddr
|
|
#define tw_v6_daddr __tw_common.skc_v6_daddr
|
|
#define tw_rcv_saddr __tw_common.skc_rcv_saddr
|
|
#define tw_v6_rcv_saddr __tw_common.skc_v6_rcv_saddr
|
|
#define tw_dport __tw_common.skc_dport
|
|
#define tw_num __tw_common.skc_num
|
|
#define tw_cookie __tw_common.skc_cookie
|
|
#define tw_dr __tw_common.skc_tw_dr
|
|
|
|
__u32 tw_mark;
|
|
volatile unsigned char tw_substate;
|
|
unsigned char tw_rcv_wscale;
|
|
|
|
/* Socket demultiplex comparisons on incoming packets. */
|
|
/* these three are in inet_sock */
|
|
__be16 tw_sport;
|
|
/* And these are ours. */
|
|
unsigned int tw_transparent : 1,
|
|
tw_flowlabel : 20,
|
|
tw_usec_ts : 1,
|
|
tw_pad : 2, /* 2 bits hole */
|
|
tw_tos : 8;
|
|
u32 tw_txhash;
|
|
u32 tw_priority;
|
|
struct timer_list tw_timer;
|
|
struct inet_bind_bucket *tw_tb;
|
|
struct inet_bind2_bucket *tw_tb2;
|
|
struct hlist_node tw_bind2_node;
|
|
};
|
|
#define tw_tclass tw_tos
|
|
|
|
#define twsk_for_each_bound_bhash2(__tw, list) \
|
|
hlist_for_each_entry(__tw, list, tw_bind2_node)
|
|
|
|
static inline struct inet_timewait_sock *inet_twsk(const struct sock *sk)
|
|
{
|
|
return (struct inet_timewait_sock *)sk;
|
|
}
|
|
|
|
void inet_twsk_free(struct inet_timewait_sock *tw);
|
|
void inet_twsk_put(struct inet_timewait_sock *tw);
|
|
|
|
void inet_twsk_bind_unhash(struct inet_timewait_sock *tw,
|
|
struct inet_hashinfo *hashinfo);
|
|
|
|
struct inet_timewait_sock *inet_twsk_alloc(const struct sock *sk,
|
|
struct inet_timewait_death_row *dr,
|
|
const int state);
|
|
|
|
void inet_twsk_hashdance(struct inet_timewait_sock *tw, struct sock *sk,
|
|
struct inet_hashinfo *hashinfo);
|
|
|
|
void __inet_twsk_schedule(struct inet_timewait_sock *tw, int timeo,
|
|
bool rearm);
|
|
|
|
static inline void inet_twsk_schedule(struct inet_timewait_sock *tw, int timeo)
|
|
{
|
|
__inet_twsk_schedule(tw, timeo, false);
|
|
}
|
|
|
|
static inline void inet_twsk_reschedule(struct inet_timewait_sock *tw, int timeo)
|
|
{
|
|
__inet_twsk_schedule(tw, timeo, true);
|
|
}
|
|
|
|
void inet_twsk_deschedule_put(struct inet_timewait_sock *tw);
|
|
|
|
void inet_twsk_purge(struct inet_hashinfo *hashinfo, int family);
|
|
|
|
static inline
|
|
struct net *twsk_net(const struct inet_timewait_sock *twsk)
|
|
{
|
|
return read_pnet(&twsk->tw_net);
|
|
}
|
|
|
|
static inline
|
|
void twsk_net_set(struct inet_timewait_sock *twsk, struct net *net)
|
|
{
|
|
write_pnet(&twsk->tw_net, net);
|
|
}
|
|
#endif /* _INET_TIMEWAIT_SOCK_ */
|