gems-kernel/source/THIRDPARTY/xnu/bsd/netinet/tcp_timer.c
2024-06-03 11:29:39 -05:00

3058 lines
88 KiB
C

/*
* Copyright (c) 2000-2020 Apple Inc. All rights reserved.
*
* @APPLE_OSREFERENCE_LICENSE_HEADER_START@
*
* This file contains Original Code and/or Modifications of Original Code
* as defined in and that are subject to the Apple Public Source License
* Version 2.0 (the 'License'). You may not use this file except in
* compliance with the License. The rights granted to you under the License
* may not be used to create, or enable the creation or redistribution of,
* unlawful or unlicensed copies of an Apple operating system, or to
* circumvent, violate, or enable the circumvention or violation of, any
* terms of an Apple operating system software license agreement.
*
* Please obtain a copy of the License at
* http://www.opensource.apple.com/apsl/ and read it before using this file.
*
* The Original Code and all software distributed under the License are
* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
* Please see the License for the specific language governing rights and
* limitations under the License.
*
* @APPLE_OSREFERENCE_LICENSE_HEADER_END@
*/
/*
* Copyright (c) 1982, 1986, 1988, 1990, 1993, 1995
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)tcp_timer.c 8.2 (Berkeley) 5/24/95
* $FreeBSD: src/sys/netinet/tcp_timer.c,v 1.34.2.11 2001/08/22 00:59:12 silby Exp $
*/
#include "tcp_includes.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/mbuf.h>
#include <sys/sysctl.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/protosw.h>
#include <sys/domain.h>
#include <sys/mcache.h>
#include <sys/queue.h>
#include <kern/locks.h>
#include <kern/cpu_number.h> /* before tcp_seq.h, for tcp_random18() */
#include <mach/boolean.h>
#include <net/route.h>
#include <net/if_var.h>
#include <net/ntstat.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/in_pcb.h>
#include <netinet/in_var.h>
#include <netinet6/in6_pcb.h>
#include <netinet/ip_var.h>
#include <netinet/tcp.h>
#include <netinet/tcp_cache.h>
#include <netinet/tcp_fsm.h>
#include <netinet/tcp_seq.h>
#include <netinet/tcp_timer.h>
#include <netinet/tcp_var.h>
#include <netinet/tcp_cc.h>
#include <netinet6/tcp6_var.h>
#include <netinet/tcpip.h>
#if TCPDEBUG
#include <netinet/tcp_debug.h>
#endif
#include <netinet/tcp_log.h>
#include <sys/kdebug.h>
#include <mach/sdt.h>
#include <netinet/mptcp_var.h>
#include <net/content_filter.h>
#include <net/sockaddr_utils.h>
/* Max number of times a stretch ack can be delayed on a connection */
#define TCP_STRETCHACK_DELAY_THRESHOLD 5
/*
* If the host processor has been sleeping for too long, this is the threshold
* used to avoid sending stale retransmissions.
*/
#define TCP_SLEEP_TOO_LONG (10 * 60 * 1000) /* 10 minutes in ms */
/* tcp timer list */
struct tcptimerlist tcp_timer_list;
/* List of pcbs in timewait state, protected by tcbinfo's ipi_lock */
struct tcptailq tcp_tw_tailq;
static int
sysctl_msec_to_ticks SYSCTL_HANDLER_ARGS
{
#pragma unused(arg2)
int error, temp;
long s, tt;
tt = *(int *)arg1;
s = tt * 1000 / TCP_RETRANSHZ;
if (tt < 0 || s > INT_MAX) {
return EINVAL;
}
temp = (int)s;
error = sysctl_handle_int(oidp, &temp, 0, req);
if (error || !req->newptr) {
return error;
}
tt = (long)temp * TCP_RETRANSHZ / 1000;
if (tt < 1 || tt > INT_MAX) {
return EINVAL;
}
*(int *)arg1 = (int)tt;
SYSCTL_SKMEM_UPDATE_AT_OFFSET(arg2, *(int*)arg1);
return 0;
}
#if SYSCTL_SKMEM
int tcp_keepinit = TCPTV_KEEP_INIT;
SYSCTL_PROC(_net_inet_tcp, TCPCTL_KEEPINIT, keepinit,
CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_LOCKED,
&tcp_keepinit, offsetof(skmem_sysctl, tcp.keepinit),
sysctl_msec_to_ticks, "I", "");
int tcp_keepidle = TCPTV_KEEP_IDLE;
SYSCTL_PROC(_net_inet_tcp, TCPCTL_KEEPIDLE, keepidle,
CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_LOCKED,
&tcp_keepidle, offsetof(skmem_sysctl, tcp.keepidle),
sysctl_msec_to_ticks, "I", "");
int tcp_keepintvl = TCPTV_KEEPINTVL;
SYSCTL_PROC(_net_inet_tcp, TCPCTL_KEEPINTVL, keepintvl,
CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_LOCKED,
&tcp_keepintvl, offsetof(skmem_sysctl, tcp.keepintvl),
sysctl_msec_to_ticks, "I", "");
SYSCTL_SKMEM_TCP_INT(OID_AUTO, keepcnt,
CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_LOCKED,
int, tcp_keepcnt, TCPTV_KEEPCNT, "number of times to repeat keepalive");
int tcp_msl = TCPTV_MSL;
SYSCTL_PROC(_net_inet_tcp, OID_AUTO, msl,
CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_LOCKED,
&tcp_msl, offsetof(skmem_sysctl, tcp.msl),
sysctl_msec_to_ticks, "I", "Maximum segment lifetime");
#else /* SYSCTL_SKMEM */
int tcp_keepinit;
SYSCTL_PROC(_net_inet_tcp, TCPCTL_KEEPINIT, keepinit,
CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_LOCKED,
&tcp_keepinit, 0, sysctl_msec_to_ticks, "I", "");
int tcp_keepidle;
SYSCTL_PROC(_net_inet_tcp, TCPCTL_KEEPIDLE, keepidle,
CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_LOCKED,
&tcp_keepidle, 0, sysctl_msec_to_ticks, "I", "");
int tcp_keepintvl;
SYSCTL_PROC(_net_inet_tcp, TCPCTL_KEEPINTVL, keepintvl,
CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_LOCKED,
&tcp_keepintvl, 0, sysctl_msec_to_ticks, "I", "");
int tcp_keepcnt;
SYSCTL_INT(_net_inet_tcp, OID_AUTO, keepcnt,
CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_LOCKED,
&tcp_keepcnt, 0, "number of times to repeat keepalive");
int tcp_msl;
SYSCTL_PROC(_net_inet_tcp, OID_AUTO, msl,
CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_LOCKED,
&tcp_msl, 0, sysctl_msec_to_ticks, "I", "Maximum segment lifetime");
#endif /* SYSCTL_SKMEM */
/*
* Avoid DoS with connections half-closed in TIME_WAIT_2
*/
int tcp_fin_timeout = TCPTV_FINWAIT2;
static int
sysctl_tcp_fin_timeout SYSCTL_HANDLER_ARGS
{
#pragma unused(arg2)
int error;
int value = tcp_fin_timeout;
error = sysctl_handle_int(oidp, &value, 0, req);
if (error != 0 || req->newptr == USER_ADDR_NULL) {
return error;
}
if (value == -1) {
/* Reset to default value */
value = TCPTV_FINWAIT2;
} else {
/* Convert from milliseconds */
long big_value = value * TCP_RETRANSHZ / 1000;
if (big_value < 0 || big_value > INT_MAX) {
return EINVAL;
}
value = (int)big_value;
}
tcp_fin_timeout = value;
SYSCTL_SKMEM_UPDATE_AT_OFFSET(arg2, value);
return 0;
}
#if SYSCTL_SKMEM
SYSCTL_PROC(_net_inet_tcp, OID_AUTO, fin_timeout,
CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_LOCKED,
&tcp_fin_timeout, offsetof(skmem_sysctl, tcp.fin_timeout),
sysctl_tcp_fin_timeout, "I", "");
#else /* SYSCTL_SKMEM */
SYSCTL_PROC(_net_inet_tcp, OID_AUTO, fin_timeout,
CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_LOCKED,
&tcp_fin_timeout, 0,
sysctl_tcp_fin_timeout, "I", "");
#endif /* SYSCTL_SKMEM */
/*
* Avoid DoS via TCP Robustness in Persist Condition
* (see http://www.ietf.org/id/draft-ananth-tcpm-persist-02.txt)
* by allowing a system wide maximum persistence timeout value when in
* Zero Window Probe mode.
*
* Expressed in milliseconds to be consistent without timeout related
* values, the TCP socket option is in seconds.
*/
#if SYSCTL_SKMEM
u_int32_t tcp_max_persist_timeout = 0;
SYSCTL_PROC(_net_inet_tcp, OID_AUTO, max_persist_timeout,
CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_LOCKED,
&tcp_max_persist_timeout, offsetof(skmem_sysctl, tcp.max_persist_timeout),
sysctl_msec_to_ticks, "I", "Maximum persistence timeout for ZWP");
#else /* SYSCTL_SKMEM */
u_int32_t tcp_max_persist_timeout = 0;
SYSCTL_PROC(_net_inet_tcp, OID_AUTO, max_persist_timeout,
CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_LOCKED,
&tcp_max_persist_timeout, 0, sysctl_msec_to_ticks, "I",
"Maximum persistence timeout for ZWP");
#endif /* SYSCTL_SKMEM */
SYSCTL_SKMEM_TCP_INT(OID_AUTO, always_keepalive,
CTLFLAG_RW | CTLFLAG_LOCKED, static int, always_keepalive, 0,
"Assume SO_KEEPALIVE on all TCP connections");
/*
* This parameter determines how long the timer list will stay in fast or
* quick mode even though all connections are idle. In this state, the
* timer will run more frequently anticipating new data.
*/
SYSCTL_SKMEM_TCP_INT(OID_AUTO, timer_fastmode_idlemax,
CTLFLAG_RW | CTLFLAG_LOCKED, int, timer_fastmode_idlemax,
TCP_FASTMODE_IDLERUN_MAX, "Maximum idle generations in fast mode");
/*
* See tcp_syn_backoff[] for interval values between SYN retransmits;
* the value set below defines the number of retransmits, before we
* disable the timestamp and window scaling options during subsequent
* SYN retransmits. Setting it to 0 disables the dropping off of those
* two options.
*/
SYSCTL_SKMEM_TCP_INT(OID_AUTO, broken_peer_syn_rexmit_thres,
CTLFLAG_RW | CTLFLAG_LOCKED, static int, tcp_broken_peer_syn_rxmit_thres,
10, "Number of retransmitted SYNs before disabling RFC 1323 "
"options on local connections");
static int tcp_timer_advanced = 0;
SYSCTL_INT(_net_inet_tcp, OID_AUTO, tcp_timer_advanced,
CTLFLAG_RD | CTLFLAG_LOCKED, &tcp_timer_advanced, 0,
"Number of times one of the timers was advanced");
static int tcp_resched_timerlist = 0;
SYSCTL_INT(_net_inet_tcp, OID_AUTO, tcp_resched_timerlist,
CTLFLAG_RD | CTLFLAG_LOCKED, &tcp_resched_timerlist, 0,
"Number of times timer list was rescheduled as part of processing a packet");
SYSCTL_SKMEM_TCP_INT(OID_AUTO, pmtud_blackhole_detection,
CTLFLAG_RW | CTLFLAG_LOCKED, int, tcp_pmtud_black_hole_detect, 1,
"Path MTU Discovery Black Hole Detection");
SYSCTL_SKMEM_TCP_INT(OID_AUTO, pmtud_blackhole_mss,
CTLFLAG_RW | CTLFLAG_LOCKED, int, tcp_pmtud_black_hole_mss, 1200,
"Path MTU Discovery Black Hole Detection lowered MSS");
#if (DEBUG || DEVELOPMENT)
int tcp_probe_if_fix_port = 0;
SYSCTL_INT(_net_inet_tcp, OID_AUTO, probe_if_fix_port,
CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_LOCKED,
&tcp_probe_if_fix_port, 0, "");
#endif /* (DEBUG || DEVELOPMENT) */
static u_int32_t tcp_mss_rec_medium = 1200;
static u_int32_t tcp_mss_rec_low = 512;
#define TCP_REPORT_STATS_INTERVAL 43200 /* 12 hours, in seconds */
int tcp_report_stats_interval = TCP_REPORT_STATS_INTERVAL;
/* performed garbage collection of "used" sockets */
static boolean_t tcp_gc_done = FALSE;
/* max idle probes */
int tcp_maxpersistidle = TCPTV_KEEP_IDLE;
/*
* TCP delack timer is set to 100 ms. Since the processing of timer list
* in fast mode will happen no faster than 100 ms, the delayed ack timer
* will fire some where between 100 and 200 ms.
*/
int tcp_delack = TCP_RETRANSHZ / 10;
#if MPTCP
/*
* MP_JOIN retransmission of 3rd ACK will be every 500 msecs without backoff
*/
int tcp_jack_rxmt = TCP_RETRANSHZ / 2;
#endif /* MPTCP */
static boolean_t tcp_itimer_done = FALSE;
static void tcp_remove_timer(struct tcpcb *tp);
static void tcp_sched_timerlist(uint32_t offset);
static u_int32_t tcp_run_conn_timer(struct tcpcb *tp, u_int16_t *mode,
u_int16_t probe_if_index);
static inline void tcp_set_lotimer_index(struct tcpcb *);
__private_extern__ void tcp_remove_from_time_wait(struct inpcb *inp);
static inline void tcp_update_mss_core(struct tcpcb *tp, struct ifnet *ifp);
__private_extern__ void tcp_report_stats(void);
static u_int64_t tcp_last_report_time;
/*
* Structure to store previously reported stats so that we can send
* incremental changes in each report interval.
*/
struct tcp_last_report_stats {
u_int32_t tcps_connattempt;
u_int32_t tcps_accepts;
u_int32_t tcps_ecn_client_setup;
u_int32_t tcps_ecn_server_setup;
u_int32_t tcps_ecn_client_success;
u_int32_t tcps_ecn_server_success;
u_int32_t tcps_ecn_not_supported;
u_int32_t tcps_ecn_lost_syn;
u_int32_t tcps_ecn_lost_synack;
u_int32_t tcps_ecn_recv_ce;
u_int32_t tcps_ecn_recv_ece;
u_int32_t tcps_ecn_sent_ece;
u_int32_t tcps_ecn_conn_recv_ce;
u_int32_t tcps_ecn_conn_recv_ece;
u_int32_t tcps_ecn_conn_plnoce;
u_int32_t tcps_ecn_conn_pl_ce;
u_int32_t tcps_ecn_conn_nopl_ce;
u_int32_t tcps_ecn_fallback_synloss;
u_int32_t tcps_ecn_fallback_reorder;
u_int32_t tcps_ecn_fallback_ce;
/* TFO-related statistics */
u_int32_t tcps_tfo_syn_data_rcv;
u_int32_t tcps_tfo_cookie_req_rcv;
u_int32_t tcps_tfo_cookie_sent;
u_int32_t tcps_tfo_cookie_invalid;
u_int32_t tcps_tfo_cookie_req;
u_int32_t tcps_tfo_cookie_rcv;
u_int32_t tcps_tfo_syn_data_sent;
u_int32_t tcps_tfo_syn_data_acked;
u_int32_t tcps_tfo_syn_loss;
u_int32_t tcps_tfo_blackhole;
u_int32_t tcps_tfo_cookie_wrong;
u_int32_t tcps_tfo_no_cookie_rcv;
u_int32_t tcps_tfo_heuristics_disable;
u_int32_t tcps_tfo_sndblackhole;
/* MPTCP-related statistics */
u_int32_t tcps_mptcp_handover_attempt;
u_int32_t tcps_mptcp_interactive_attempt;
u_int32_t tcps_mptcp_aggregate_attempt;
u_int32_t tcps_mptcp_fp_handover_attempt;
u_int32_t tcps_mptcp_fp_interactive_attempt;
u_int32_t tcps_mptcp_fp_aggregate_attempt;
u_int32_t tcps_mptcp_heuristic_fallback;
u_int32_t tcps_mptcp_fp_heuristic_fallback;
u_int32_t tcps_mptcp_handover_success_wifi;
u_int32_t tcps_mptcp_handover_success_cell;
u_int32_t tcps_mptcp_interactive_success;
u_int32_t tcps_mptcp_aggregate_success;
u_int32_t tcps_mptcp_fp_handover_success_wifi;
u_int32_t tcps_mptcp_fp_handover_success_cell;
u_int32_t tcps_mptcp_fp_interactive_success;
u_int32_t tcps_mptcp_fp_aggregate_success;
u_int32_t tcps_mptcp_handover_cell_from_wifi;
u_int32_t tcps_mptcp_handover_wifi_from_cell;
u_int32_t tcps_mptcp_interactive_cell_from_wifi;
u_int64_t tcps_mptcp_handover_cell_bytes;
u_int64_t tcps_mptcp_interactive_cell_bytes;
u_int64_t tcps_mptcp_aggregate_cell_bytes;
u_int64_t tcps_mptcp_handover_all_bytes;
u_int64_t tcps_mptcp_interactive_all_bytes;
u_int64_t tcps_mptcp_aggregate_all_bytes;
u_int32_t tcps_mptcp_back_to_wifi;
u_int32_t tcps_mptcp_wifi_proxy;
u_int32_t tcps_mptcp_cell_proxy;
u_int32_t tcps_mptcp_triggered_cell;
};
/* Returns true if the timer is on the timer list */
#define TIMER_IS_ON_LIST(tp) ((tp)->t_flags & TF_TIMER_ONLIST)
/* Run the TCP timerlist atleast once every hour */
#define TCP_TIMERLIST_MAX_OFFSET (60 * 60 * TCP_RETRANSHZ)
static void add_to_time_wait_locked(struct tcpcb *tp, uint32_t delay);
static boolean_t tcp_garbage_collect(struct inpcb *, int);
#define TIMERENTRY_TO_TP(te) ((struct tcpcb *)((uintptr_t)te - offsetof(struct tcpcb, tentry.le.le_next)))
#define VERIFY_NEXT_LINK(elm, field) do { \
if (LIST_NEXT((elm),field) != NULL && \
LIST_NEXT((elm),field)->field.le_prev != \
&((elm)->field.le_next)) \
panic("Bad link elm %p next->prev != elm", (elm)); \
} while(0)
#define VERIFY_PREV_LINK(elm, field) do { \
if (*(elm)->field.le_prev != (elm)) \
panic("Bad link elm %p prev->next != elm", (elm)); \
} while(0)
#define TCP_SET_TIMER_MODE(mode, i) do { \
if (IS_TIMER_HZ_10MS(i)) \
(mode) |= TCP_TIMERLIST_10MS_MODE; \
else if (IS_TIMER_HZ_100MS(i)) \
(mode) |= TCP_TIMERLIST_100MS_MODE; \
else \
(mode) |= TCP_TIMERLIST_500MS_MODE; \
} while(0)
#if (DEVELOPMENT || DEBUG)
SYSCTL_UINT(_net_inet_tcp, OID_AUTO, mss_rec_medium,
CTLFLAG_RW | CTLFLAG_LOCKED, &tcp_mss_rec_medium, 0,
"Medium MSS based on recommendation in link status report");
SYSCTL_UINT(_net_inet_tcp, OID_AUTO, mss_rec_low,
CTLFLAG_RW | CTLFLAG_LOCKED, &tcp_mss_rec_low, 0,
"Low MSS based on recommendation in link status report");
static int32_t tcp_change_mss_recommended = 0;
static int
sysctl_change_mss_recommended SYSCTL_HANDLER_ARGS
{
#pragma unused(oidp, arg1, arg2)
int i, err = 0, changed = 0;
struct ifnet *ifp;
struct if_link_status ifsr;
struct if_cellular_status_v1 *new_cell_sr;
err = sysctl_io_number(req, tcp_change_mss_recommended,
sizeof(int32_t), &i, &changed);
if (changed) {
if (i < 0 || i > UINT16_MAX) {
return EINVAL;
}
ifnet_head_lock_shared();
TAILQ_FOREACH(ifp, &ifnet_head, if_link) {
if (IFNET_IS_CELLULAR(ifp)) {
bzero(&ifsr, sizeof(ifsr));
new_cell_sr = &ifsr.ifsr_u.ifsr_cell.if_cell_u.if_status_v1;
ifsr.ifsr_version = IF_CELLULAR_STATUS_REPORT_CURRENT_VERSION;
ifsr.ifsr_len = sizeof(*new_cell_sr);
/* Set MSS recommended */
new_cell_sr->valid_bitmask |= IF_CELL_UL_MSS_RECOMMENDED_VALID;
new_cell_sr->mss_recommended = (uint16_t)i;
err = ifnet_link_status_report(ifp, new_cell_sr, sizeof(new_cell_sr));
if (err == 0) {
tcp_change_mss_recommended = i;
} else {
break;
}
}
}
ifnet_head_done();
}
return err;
}
SYSCTL_PROC(_net_inet_tcp, OID_AUTO, change_mss_recommended,
CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_LOCKED, &tcp_change_mss_recommended,
0, sysctl_change_mss_recommended, "IU", "Change MSS recommended");
SYSCTL_INT(_net_inet_tcp, OID_AUTO, report_stats_interval,
CTLFLAG_RW | CTLFLAG_LOCKED, &tcp_report_stats_interval, 0,
"Report stats interval");
#endif /* (DEVELOPMENT || DEBUG) */
/*
* Macro to compare two timers. If there is a reset of the sign bit,
* it is safe to assume that the timer has wrapped around. By doing
* signed comparision, we take care of wrap around such that the value
* with the sign bit reset is actually ahead of the other.
*/
inline int32_t
timer_diff(uint32_t t1, uint32_t toff1, uint32_t t2, uint32_t toff2)
{
return (int32_t)((t1 + toff1) - (t2 + toff2));
}
/*
* Add to tcp timewait list, delay is given in milliseconds.
*/
static void
add_to_time_wait_locked(struct tcpcb *tp, uint32_t delay)
{
struct inpcbinfo *pcbinfo = &tcbinfo;
struct inpcb *inp = tp->t_inpcb;
uint32_t timer;
/* pcb list should be locked when we get here */
LCK_RW_ASSERT(&pcbinfo->ipi_lock, LCK_RW_ASSERT_EXCLUSIVE);
/* We may get here multiple times, so check */
if (!(inp->inp_flags2 & INP2_TIMEWAIT)) {
pcbinfo->ipi_twcount++;
inp->inp_flags2 |= INP2_TIMEWAIT;
/* Remove from global inp list */
LIST_REMOVE(inp, inp_list);
} else {
TAILQ_REMOVE(&tcp_tw_tailq, tp, t_twentry);
}
/* Compute the time at which this socket can be closed */
timer = tcp_now + delay;
/* We will use the TCPT_2MSL timer for tracking this delay */
if (TIMER_IS_ON_LIST(tp)) {
tcp_remove_timer(tp);
}
tp->t_timer[TCPT_2MSL] = timer;
TAILQ_INSERT_TAIL(&tcp_tw_tailq, tp, t_twentry);
}
void
add_to_time_wait(struct tcpcb *tp, uint32_t delay)
{
if (tp->t_inpcb->inp_socket->so_options & SO_NOWAKEFROMSLEEP) {
socket_post_kev_msg_closed(tp->t_inpcb->inp_socket);
}
tcp_del_fsw_flow(tp);
/* 19182803: Notify nstat that connection is closing before waiting. */
nstat_pcb_detach(tp->t_inpcb);
#if CONTENT_FILTER
if ((tp->t_inpcb->inp_socket->so_flags & SOF_CONTENT_FILTER) != 0) {
/* If filter present, allow filter to finish processing all queued up data before adding to time wait queue */
(void) cfil_sock_tcp_add_time_wait(tp->t_inpcb->inp_socket);
} else
#endif /* CONTENT_FILTER */
{
add_to_time_wait_now(tp, delay);
}
}
void
add_to_time_wait_now(struct tcpcb *tp, uint32_t delay)
{
struct inpcbinfo *pcbinfo = &tcbinfo;
if (!lck_rw_try_lock_exclusive(&pcbinfo->ipi_lock)) {
socket_unlock(tp->t_inpcb->inp_socket, 0);
lck_rw_lock_exclusive(&pcbinfo->ipi_lock);
socket_lock(tp->t_inpcb->inp_socket, 0);
}
add_to_time_wait_locked(tp, delay);
lck_rw_done(&pcbinfo->ipi_lock);
inpcb_gc_sched(pcbinfo, INPCB_TIMER_LAZY);
}
/* If this is on time wait queue, remove it. */
void
tcp_remove_from_time_wait(struct inpcb *inp)
{
struct tcpcb *tp = intotcpcb(inp);
if (inp->inp_flags2 & INP2_TIMEWAIT) {
TAILQ_REMOVE(&tcp_tw_tailq, tp, t_twentry);
}
}
static boolean_t
tcp_garbage_collect(struct inpcb *inp, int istimewait)
{
boolean_t active = FALSE;
struct socket *so, *mp_so = NULL;
struct tcpcb *tp;
so = inp->inp_socket;
tp = intotcpcb(inp);
if (so->so_flags & SOF_MP_SUBFLOW) {
mp_so = mptetoso(tptomptp(tp)->mpt_mpte);
if (!socket_try_lock(mp_so)) {
mp_so = NULL;
active = TRUE;
goto out;
}
if (mpsotomppcb(mp_so)->mpp_inside > 0) {
os_log(mptcp_log_handle, "%s - %lx: Still inside %d usecount %d\n", __func__,
(unsigned long)VM_KERNEL_ADDRPERM(mpsotompte(mp_so)),
mpsotomppcb(mp_so)->mpp_inside,
mp_so->so_usecount);
socket_unlock(mp_so, 0);
mp_so = NULL;
active = TRUE;
goto out;
}
/* We call socket_unlock with refcount further below */
mp_so->so_usecount++;
tptomptp(tp)->mpt_mpte->mpte_mppcb->mpp_inside++;
}
/*
* Skip if still in use or busy; it would have been more efficient
* if we were to test so_usecount against 0, but this isn't possible
* due to the current implementation of tcp_dropdropablreq() where
* overflow sockets that are eligible for garbage collection have
* their usecounts set to 1.
*/
if (!lck_mtx_try_lock_spin(&inp->inpcb_mtx)) {
active = TRUE;
goto out;
}
/* Check again under the lock */
if (so->so_usecount > 1) {
if (inp->inp_wantcnt == WNT_STOPUSING) {
active = TRUE;
}
lck_mtx_unlock(&inp->inpcb_mtx);
goto out;
}
if (istimewait && TSTMP_GEQ(tcp_now, tp->t_timer[TCPT_2MSL]) &&
tp->t_state != TCPS_CLOSED) {
/* Become a regular mutex */
lck_mtx_convert_spin(&inp->inpcb_mtx);
tcp_close(tp);
}
/*
* Overflowed socket dropped from the listening queue? Do this
* only if we are called to clean up the time wait slots, since
* tcp_dropdropablreq() considers a socket to have been fully
* dropped after add_to_time_wait() is finished.
* Also handle the case of connections getting closed by the peer
* while in the queue as seen with rdar://6422317
*
*/
if (so->so_usecount == 1 &&
((istimewait && (so->so_flags & SOF_OVERFLOW)) ||
((tp != NULL) && (tp->t_state == TCPS_CLOSED) &&
(so->so_head != NULL) &&
((so->so_state & (SS_INCOMP | SS_CANTSENDMORE | SS_CANTRCVMORE)) ==
(SS_INCOMP | SS_CANTSENDMORE | SS_CANTRCVMORE))))) {
if (inp->inp_state != INPCB_STATE_DEAD) {
/* Become a regular mutex */
lck_mtx_convert_spin(&inp->inpcb_mtx);
if (SOCK_CHECK_DOM(so, PF_INET6)) {
in6_pcbdetach(inp);
} else {
in_pcbdetach(inp);
}
}
VERIFY(so->so_usecount > 0);
so->so_usecount--;
if (inp->inp_wantcnt == WNT_STOPUSING) {
active = TRUE;
}
lck_mtx_unlock(&inp->inpcb_mtx);
goto out;
} else if (inp->inp_wantcnt != WNT_STOPUSING) {
lck_mtx_unlock(&inp->inpcb_mtx);
active = FALSE;
goto out;
}
/*
* We get here because the PCB is no longer searchable
* (WNT_STOPUSING); detach (if needed) and dispose if it is dead
* (usecount is 0). This covers all cases, including overflow
* sockets and those that are considered as "embryonic",
* i.e. created by sonewconn() in TCP input path, and have
* not yet been committed. For the former, we reduce the usecount
* to 0 as done by the code above. For the latter, the usecount
* would have reduced to 0 as part calling soabort() when the
* socket is dropped at the end of tcp_input().
*/
if (so->so_usecount == 0) {
DTRACE_TCP4(state__change, void, NULL, struct inpcb *, inp,
struct tcpcb *, tp, int32_t, TCPS_CLOSED);
/* Become a regular mutex */
lck_mtx_convert_spin(&inp->inpcb_mtx);
/*
* If this tp still happens to be on the timer list,
* take it out
*/
if (TIMER_IS_ON_LIST(tp)) {
tcp_remove_timer(tp);
}
if (inp->inp_state != INPCB_STATE_DEAD) {
if (SOCK_CHECK_DOM(so, PF_INET6)) {
in6_pcbdetach(inp);
} else {
in_pcbdetach(inp);
}
}
if (mp_so) {
mptcp_subflow_del(tptomptp(tp)->mpt_mpte, tp->t_mpsub);
/* so is now unlinked from mp_so - let's drop the lock */
socket_unlock(mp_so, 1);
mp_so = NULL;
}
in_pcbdispose(inp);
active = FALSE;
goto out;
}
lck_mtx_unlock(&inp->inpcb_mtx);
active = TRUE;
out:
if (mp_so) {
socket_unlock(mp_so, 1);
}
return active;
}
/*
* TCP garbage collector callback (inpcb_timer_func_t).
*
* Returns the number of pcbs that will need to be gc-ed soon,
* returnining > 0 will keep timer active.
*/
void
tcp_gc(struct inpcbinfo *ipi)
{
struct inpcb *inp, *nxt;
struct tcpcb *tw_tp, *tw_ntp;
#if TCPDEBUG
int ostate;
#endif
#if KDEBUG
static int tws_checked = 0;
#endif
KERNEL_DEBUG(DBG_FNC_TCP_SLOW | DBG_FUNC_START, 0, 0, 0, 0, 0);
/*
* Update tcp_now here as it may get used while
* processing the slow timer.
*/
calculate_tcp_clock();
/*
* Garbage collect socket/tcpcb: We need to acquire the list lock
* exclusively to do this
*/
if (lck_rw_try_lock_exclusive(&ipi->ipi_lock) == FALSE) {
/* don't sweat it this time; cleanup was done last time */
if (tcp_gc_done == TRUE) {
tcp_gc_done = FALSE;
KERNEL_DEBUG(DBG_FNC_TCP_SLOW | DBG_FUNC_END,
tws_checked, cur_tw_slot, 0, 0, 0);
/* Lock upgrade failed, give up this round */
os_atomic_inc(&ipi->ipi_gc_req.intimer_fast, relaxed);
return;
}
/* Upgrade failed, lost lock now take it again exclusive */
lck_rw_lock_exclusive(&ipi->ipi_lock);
}
tcp_gc_done = TRUE;
LIST_FOREACH_SAFE(inp, &tcb, inp_list, nxt) {
if (tcp_garbage_collect(inp, 0)) {
os_atomic_inc(&ipi->ipi_gc_req.intimer_fast, relaxed);
}
}
/* Now cleanup the time wait ones */
TAILQ_FOREACH_SAFE(tw_tp, &tcp_tw_tailq, t_twentry, tw_ntp) {
/*
* We check the timestamp here without holding the
* socket lock for better performance. If there are
* any pcbs in time-wait, the timer will get rescheduled.
* Hence some error in this check can be tolerated.
*
* Sometimes a socket on time-wait queue can be closed if
* 2MSL timer expired but the application still has a
* usecount on it.
*/
if (tw_tp->t_state == TCPS_CLOSED ||
TSTMP_GEQ(tcp_now, tw_tp->t_timer[TCPT_2MSL])) {
if (tcp_garbage_collect(tw_tp->t_inpcb, 1)) {
os_atomic_inc(&ipi->ipi_gc_req.intimer_lazy, relaxed);
}
}
}
/* take into account pcbs that are still in time_wait_slots */
os_atomic_add(&ipi->ipi_gc_req.intimer_lazy, ipi->ipi_twcount, relaxed);
lck_rw_done(&ipi->ipi_lock);
/* Clean up the socache while we are here */
if (so_cache_timer()) {
os_atomic_inc(&ipi->ipi_gc_req.intimer_lazy, relaxed);
}
KERNEL_DEBUG(DBG_FNC_TCP_SLOW | DBG_FUNC_END, tws_checked,
cur_tw_slot, 0, 0, 0);
return;
}
/*
* Cancel all timers for TCP tp.
*/
void
tcp_canceltimers(struct tcpcb *tp)
{
int i;
tcp_remove_timer(tp);
for (i = 0; i < TCPT_NTIMERS; i++) {
tp->t_timer[i] = 0;
}
tp->tentry.timer_start = tcp_now;
tp->tentry.index = TCPT_NONE;
}
int tcp_syn_backoff[TCP_MAXRXTSHIFT + 1] =
{ 1, 1, 1, 1, 1, 2, 4, 8, 16, 32, 64, 64, 64 };
int tcp_backoff[TCP_MAXRXTSHIFT + 1] =
{ 1, 2, 4, 8, 16, 32, 64, 64, 64, 64, 64, 64, 64 };
static int tcp_totbackoff = 511; /* sum of tcp_backoff[] */
void
tcp_rexmt_save_state(struct tcpcb *tp)
{
u_int32_t fsize;
if (TSTMP_SUPPORTED(tp)) {
/*
* Since timestamps are supported on the connection,
* we can do recovery as described in rfc 4015.
*/
fsize = tp->snd_max - tp->snd_una;
tp->snd_ssthresh_prev = max(fsize, tp->snd_ssthresh);
tp->snd_recover_prev = tp->snd_recover;
} else {
/*
* Timestamp option is not supported on this connection.
* Record ssthresh and cwnd so they can
* be recovered if this turns out to be a "bad" retransmit.
* A retransmit is considered "bad" if an ACK for this
* segment is received within RTT/2 interval; the assumption
* here is that the ACK was already in flight. See
* "On Estimating End-to-End Network Path Properties" by
* Allman and Paxson for more details.
*/
tp->snd_cwnd_prev = tp->snd_cwnd;
tp->snd_ssthresh_prev = tp->snd_ssthresh;
tp->snd_recover_prev = tp->snd_recover;
if (IN_FASTRECOVERY(tp)) {
tp->t_flags |= TF_WASFRECOVERY;
} else {
tp->t_flags &= ~TF_WASFRECOVERY;
}
}
tp->t_srtt_prev = (tp->t_srtt >> TCP_RTT_SHIFT) + 2;
tp->t_rttvar_prev = (tp->t_rttvar >> TCP_RTTVAR_SHIFT);
tp->t_flagsext &= ~(TF_RECOMPUTE_RTT);
}
/*
* Revert to the older segment size if there is an indication that PMTU
* blackhole detection was not needed.
*/
void
tcp_pmtud_revert_segment_size(struct tcpcb *tp)
{
int32_t optlen;
VERIFY(tp->t_pmtud_saved_maxopd > 0);
tp->t_flags |= TF_PMTUD;
tp->t_flags &= ~TF_BLACKHOLE;
optlen = tp->t_maxopd - tp->t_maxseg;
tp->t_maxopd = tp->t_pmtud_saved_maxopd;
tp->t_maxseg = tp->t_maxopd - optlen;
/*
* Reset the slow-start flight size as it
* may depend on the new MSS
*/
if (CC_ALGO(tp)->cwnd_init != NULL) {
CC_ALGO(tp)->cwnd_init(tp);
}
if (TCP_USE_RLEDBAT(tp, tp->t_inpcb->inp_socket) &&
tcp_cc_rledbat.rwnd_init != NULL) {
tcp_cc_rledbat.rwnd_init(tp);
}
tp->t_pmtud_start_ts = 0;
tcpstat.tcps_pmtudbh_reverted++;
/* change MSS according to recommendation, if there was one */
tcp_update_mss_locked(tp->t_inpcb->inp_socket, NULL);
}
static uint32_t
tcp_pmtud_black_holed_next_mss(struct tcpcb *tp)
{
/* Reduce the MSS to intermediary value */
if (tp->t_maxopd > tcp_pmtud_black_hole_mss) {
return tcp_pmtud_black_hole_mss;
} else {
if (tp->t_inpcb->inp_vflag & INP_IPV4) {
return tcp_mssdflt;
} else {
return tcp_v6mssdflt;
}
}
}
/*
* Send a packet designed to force a response
* if the peer is up and reachable:
* either an ACK if the connection is still alive,
* or an RST if the peer has closed the connection
* due to timeout or reboot.
* Using sequence number tp->snd_una-1
* causes the transmitted zero-length segment
* to lie outside the receive window;
* by the protocol spec, this requires the
* correspondent TCP to respond.
*/
static bool
tcp_send_keep_alive(struct tcpcb *tp)
{
struct tcptemp *t_template;
struct mbuf *m;
tcpstat.tcps_keepprobe++;
t_template = tcp_maketemplate(tp, &m);
if (t_template != NULL) {
struct inpcb *inp = tp->t_inpcb;
struct tcp_respond_args tra;
bzero(&tra, sizeof(tra));
tra.nocell = INP_NO_CELLULAR(inp) ? 1 : 0;
tra.noexpensive = INP_NO_EXPENSIVE(inp) ? 1 : 0;
tra.noconstrained = INP_NO_CONSTRAINED(inp) ? 1 : 0;
tra.awdl_unrestricted = INP_AWDL_UNRESTRICTED(inp) ? 1 : 0;
tra.intcoproc_allowed = INP_INTCOPROC_ALLOWED(inp) ? 1 : 0;
tra.management_allowed = INP_MANAGEMENT_ALLOWED(inp) ? 1 : 0;
tra.keep_alive = 1;
if (tp->t_inpcb->inp_flags & INP_BOUND_IF) {
tra.ifscope = tp->t_inpcb->inp_boundifp->if_index;
} else {
tra.ifscope = IFSCOPE_NONE;
}
tcp_respond(tp, t_template->tt_ipgen,
&t_template->tt_t, (struct mbuf *)NULL,
tp->rcv_nxt, tp->snd_una - 1, 0, &tra);
(void) m_free(m);
return true;
} else {
return false;
}
}
/*
* TCP timer processing.
*/
struct tcpcb *
tcp_timers(struct tcpcb *tp, int timer)
{
int32_t rexmt, optlen = 0, idle_time = 0;
struct socket *so;
#if TCPDEBUG
int ostate;
#endif
u_int64_t accsleep_ms;
u_int64_t last_sleep_ms = 0;
so = tp->t_inpcb->inp_socket;
idle_time = tcp_now - tp->t_rcvtime;
switch (timer) {
/*
* 2 MSL timeout in shutdown went off. If we're closed but
* still waiting for peer to close and connection has been idle
* too long, or if 2MSL time is up from TIME_WAIT or FIN_WAIT_2,
* delete connection control block.
* Otherwise, (this case shouldn't happen) check again in a bit
* we keep the socket in the main list in that case.
*/
case TCPT_2MSL:
tcp_free_sackholes(tp);
if (tp->t_state != TCPS_TIME_WAIT &&
tp->t_state != TCPS_FIN_WAIT_2 &&
((idle_time > 0) && (idle_time < TCP_CONN_MAXIDLE(tp)))) {
tp->t_timer[TCPT_2MSL] = OFFSET_FROM_START(tp,
(u_int32_t)TCP_CONN_KEEPINTVL(tp));
} else {
if (tp->t_state == TCPS_FIN_WAIT_2) {
TCP_LOG_DROP_PCB(NULL, NULL, tp, false,
"FIN wait timeout drop");
tcpstat.tcps_fin_timeout_drops++;
tp = tcp_drop(tp, 0);
} else {
tp = tcp_close(tp);
}
return tp;
}
break;
/*
* Retransmission timer went off. Message has not
* been acked within retransmit interval. Back off
* to a longer retransmit interval and retransmit one segment.
*/
case TCPT_REXMT:
absolutetime_to_nanoseconds(mach_absolutetime_asleep,
&accsleep_ms);
accsleep_ms = accsleep_ms / 1000000UL;
if (accsleep_ms > tp->t_accsleep_ms) {
last_sleep_ms = accsleep_ms - tp->t_accsleep_ms;
}
/*
* Drop a connection in the retransmit timer
* 1. If we have retransmitted more than TCP_MAXRXTSHIFT
* times
* 2. If the time spent in this retransmission episode is
* more than the time limit set with TCP_RXT_CONNDROPTIME
* socket option
* 3. If TCP_RXT_FINDROP socket option was set and
* we have already retransmitted the FIN 3 times without
* receiving an ack
*/
if (++tp->t_rxtshift > TCP_MAXRXTSHIFT ||
(tp->t_rxt_conndroptime > 0 && tp->t_rxtstart > 0 &&
(tcp_now - tp->t_rxtstart) >= tp->t_rxt_conndroptime) ||
((tp->t_flagsext & TF_RXTFINDROP) != 0 &&
(tp->t_flags & TF_SENTFIN) != 0 && tp->t_rxtshift >= 4) ||
(tp->t_rxtshift > 4 && last_sleep_ms >= TCP_SLEEP_TOO_LONG)) {
if (tp->t_state == TCPS_ESTABLISHED &&
tp->t_rxt_minimum_timeout > 0) {
/*
* Avoid dropping a connection if minimum
* timeout is set and that time did not
* pass. We will retry sending
* retransmissions at the maximum interval
*/
if (TSTMP_LT(tcp_now, (tp->t_rxtstart +
tp->t_rxt_minimum_timeout))) {
tp->t_rxtshift = TCP_MAXRXTSHIFT - 1;
goto retransmit_packet;
}
}
if ((tp->t_flagsext & TF_RXTFINDROP) != 0) {
tcpstat.tcps_rxtfindrop++;
} else if (last_sleep_ms >= TCP_SLEEP_TOO_LONG) {
tcpstat.tcps_drop_after_sleep++;
} else {
tcpstat.tcps_timeoutdrop++;
}
if (tp->t_rxtshift >= TCP_MAXRXTSHIFT) {
if (TCP_ECN_ENABLED(tp)) {
INP_INC_IFNET_STAT(tp->t_inpcb,
ecn_on.rxmit_drop);
} else {
INP_INC_IFNET_STAT(tp->t_inpcb,
ecn_off.rxmit_drop);
}
}
tp->t_rxtshift = TCP_MAXRXTSHIFT;
soevent(so,
(SO_FILT_HINT_LOCKED | SO_FILT_HINT_TIMEOUT));
if (TCP_ECN_ENABLED(tp) &&
tp->t_state == TCPS_ESTABLISHED) {
tcp_heuristic_ecn_droprxmt(tp);
}
TCP_LOG_DROP_PCB(NULL, NULL, tp, false,
"retransmission timeout drop");
tp = tcp_drop(tp, tp->t_softerror ?
tp->t_softerror : ETIMEDOUT);
break;
}
retransmit_packet:
tcpstat.tcps_rexmttimeo++;
tp->t_accsleep_ms = accsleep_ms;
if (tp->t_rxtshift == 1 &&
tp->t_state == TCPS_ESTABLISHED) {
/* Set the time at which retransmission started. */
tp->t_rxtstart = tcp_now;
/*
* if this is the first retransmit timeout, save
* the state so that we can recover if the timeout
* is spurious.
*/
tcp_rexmt_save_state(tp);
tcp_ccdbg_trace(tp, NULL, TCP_CC_FIRST_REXMT);
}
#if MPTCP
if ((tp->t_rxtshift >= mptcp_fail_thresh) &&
(tp->t_state == TCPS_ESTABLISHED) &&
(tp->t_mpflags & TMPF_MPTCP_TRUE)) {
mptcp_act_on_txfail(so);
}
if (TCPS_HAVEESTABLISHED(tp->t_state) &&
(so->so_flags & SOF_MP_SUBFLOW)) {
struct mptses *mpte = tptomptp(tp)->mpt_mpte;
if (mpte->mpte_svctype == MPTCP_SVCTYPE_HANDOVER ||
mpte->mpte_svctype == MPTCP_SVCTYPE_PURE_HANDOVER) {
mptcp_check_subflows_and_add(mpte);
}
}
#endif /* MPTCP */
if (tp->t_adaptive_wtimo > 0 &&
tp->t_rxtshift > tp->t_adaptive_wtimo &&
TCPS_HAVEESTABLISHED(tp->t_state)) {
/* Send an event to the application */
soevent(so,
(SO_FILT_HINT_LOCKED |
SO_FILT_HINT_ADAPTIVE_WTIMO));
}
/*
* If this is a retransmit timeout after PTO, the PTO
* was not effective
*/
if (tp->t_flagsext & TF_SENT_TLPROBE) {
tp->t_flagsext &= ~(TF_SENT_TLPROBE);
tcpstat.tcps_rto_after_pto++;
}
if (tp->t_flagsext & TF_DELAY_RECOVERY) {
/*
* Retransmit timer fired before entering recovery
* on a connection with packet re-ordering. This
* suggests that the reordering metrics computed
* are not accurate.
*/
tp->t_reorderwin = 0;
tp->t_timer[TCPT_DELAYFR] = 0;
tp->t_flagsext &= ~(TF_DELAY_RECOVERY);
}
if (!(tp->t_flagsext & TF_FASTOPEN_FORCE_ENABLE) &&
tp->t_state == TCPS_SYN_RECEIVED) {
tcp_disable_tfo(tp);
}
if (!(tp->t_flagsext & TF_FASTOPEN_FORCE_ENABLE) &&
!(tp->t_tfo_flags & TFO_F_HEURISTIC_DONE) &&
(tp->t_tfo_stats & TFO_S_SYN_DATA_SENT) &&
!(tp->t_tfo_flags & TFO_F_NO_SNDPROBING) &&
((tp->t_state != TCPS_SYN_SENT && tp->t_rxtshift > 1) ||
tp->t_rxtshift > 4)) {
/*
* For regular retransmissions, a first one is being
* done for tail-loss probe.
* Thus, if rxtshift > 1, this means we have sent the segment
* a total of 3 times.
*
* If we are in SYN-SENT state, then there is no tail-loss
* probe thus we have to let rxtshift go up to 3.
*/
tcp_heuristic_tfo_middlebox(tp);
so->so_error = ENODATA;
soevent(so,
(SO_FILT_HINT_LOCKED | SO_FILT_HINT_MP_SUB_ERROR));
sorwakeup(so);
sowwakeup(so);
tp->t_tfo_stats |= TFO_S_SEND_BLACKHOLE;
tcpstat.tcps_tfo_sndblackhole++;
}
if (!(tp->t_flagsext & TF_FASTOPEN_FORCE_ENABLE) &&
!(tp->t_tfo_flags & TFO_F_HEURISTIC_DONE) &&
(tp->t_tfo_stats & TFO_S_SYN_DATA_ACKED) &&
tp->t_rxtshift > 3) {
if (TSTMP_GT(tp->t_sndtime - 10 * TCP_RETRANSHZ, tp->t_rcvtime)) {
tcp_heuristic_tfo_middlebox(tp);
so->so_error = ENODATA;
soevent(so,
(SO_FILT_HINT_LOCKED | SO_FILT_HINT_MP_SUB_ERROR));
sorwakeup(so);
sowwakeup(so);
}
}
if (tp->t_state == TCPS_SYN_SENT) {
rexmt = TCP_REXMTVAL(tp) * tcp_syn_backoff[tp->t_rxtshift];
tp->t_stat.synrxtshift = tp->t_rxtshift;
tp->t_stat.rxmitsyns++;
/* When retransmitting, disable TFO */
if (tfo_enabled(tp) &&
!(tp->t_flagsext & TF_FASTOPEN_FORCE_ENABLE)) {
tcp_disable_tfo(tp);
tp->t_tfo_flags |= TFO_F_SYN_LOSS;
}
} else {
rexmt = TCP_REXMTVAL(tp) * tcp_backoff[tp->t_rxtshift];
}
TCPT_RANGESET(tp->t_rxtcur, rexmt, tp->t_rttmin, TCPTV_REXMTMAX,
TCP_ADD_REXMTSLOP(tp));
tp->t_timer[TCPT_REXMT] = OFFSET_FROM_START(tp, tp->t_rxtcur);
TCP_LOG_RTT_INFO(tp);
if (INP_WAIT_FOR_IF_FEEDBACK(tp->t_inpcb)) {
goto fc_output;
}
tcp_free_sackholes(tp);
/*
* Check for potential Path MTU Discovery Black Hole
*/
if (tcp_pmtud_black_hole_detect &&
!(tp->t_flagsext & TF_NOBLACKHOLE_DETECTION) &&
(tp->t_state == TCPS_ESTABLISHED)) {
if ((tp->t_flags & TF_PMTUD) &&
tp->t_pmtud_lastseg_size > tcp_pmtud_black_holed_next_mss(tp) &&
tp->t_rxtshift == 2) {
/*
* Enter Path MTU Black-hole Detection mechanism:
* - Disable Path MTU Discovery (IP "DF" bit).
* - Reduce MTU to lower value than what we
* negotiated with the peer.
*/
/* Disable Path MTU Discovery for now */
tp->t_flags &= ~TF_PMTUD;
/* Record that we may have found a black hole */
tp->t_flags |= TF_BLACKHOLE;
optlen = tp->t_maxopd - tp->t_maxseg;
/* Keep track of previous MSS */
tp->t_pmtud_saved_maxopd = tp->t_maxopd;
tp->t_pmtud_start_ts = tcp_now;
if (tp->t_pmtud_start_ts == 0) {
tp->t_pmtud_start_ts++;
}
/* Reduce the MSS to intermediary value */
tp->t_maxopd = tcp_pmtud_black_holed_next_mss(tp);
tp->t_maxseg = tp->t_maxopd - optlen;
/*
* Reset the slow-start flight size
* as it may depend on the new MSS
*/
if (CC_ALGO(tp)->cwnd_init != NULL) {
CC_ALGO(tp)->cwnd_init(tp);
}
tp->snd_cwnd = tp->t_maxseg;
if (TCP_USE_RLEDBAT(tp, so) &&
tcp_cc_rledbat.rwnd_init != NULL) {
tcp_cc_rledbat.rwnd_init(tp);
}
}
/*
* If further retransmissions are still
* unsuccessful with a lowered MTU, maybe this
* isn't a Black Hole and we restore the previous
* MSS and blackhole detection flags.
*/
else {
if ((tp->t_flags & TF_BLACKHOLE) &&
(tp->t_rxtshift > 4)) {
tcp_pmtud_revert_segment_size(tp);
tp->snd_cwnd = tp->t_maxseg;
}
}
}
/*
* Disable rfc1323 and rfc1644 if we haven't got any
* response to our SYN (after we reach the threshold)
* to work-around some broken terminal servers (most of
* which have hopefully been retired) that have bad VJ
* header compression code which trashes TCP segments
* containing unknown-to-them TCP options.
* Do this only on non-local connections.
*/
if (tp->t_state == TCPS_SYN_SENT &&
tp->t_rxtshift == tcp_broken_peer_syn_rxmit_thres) {
tp->t_flags &= ~(TF_REQ_SCALE | TF_REQ_TSTMP | TF_REQ_CC);
}
/*
* If losing, let the lower level know and try for
* a better route. Also, if we backed off this far,
* our srtt estimate is probably bogus. Clobber it
* so we'll take the next rtt measurement as our srtt;
* move the current srtt into rttvar to keep the current
* retransmit times until then.
*/
if (tp->t_rxtshift > TCP_MAXRXTSHIFT / 4) {
if (!(tp->t_inpcb->inp_vflag & INP_IPV4)) {
in6_losing(tp->t_inpcb);
} else {
in_losing(tp->t_inpcb);
}
tp->t_rttvar += (tp->t_srtt >> TCP_RTT_SHIFT);
tp->t_srtt = 0;
}
tp->snd_nxt = tp->snd_una;
/*
* Note: We overload snd_recover to function also as the
* snd_last variable described in RFC 2582
*/
tp->snd_recover = tp->snd_max;
/*
* Force a segment to be sent.
*/
tp->t_flags |= TF_ACKNOW;
/* If timing a segment in this window, stop the timer */
tp->t_rtttime = 0;
if (!IN_FASTRECOVERY(tp) && tp->t_rxtshift == 1) {
tcpstat.tcps_tailloss_rto++;
}
/*
* RFC 5681 says: when a TCP sender detects segment loss
* using retransmit timer and the given segment has already
* been retransmitted by way of the retransmission timer at
* least once, the value of ssthresh is held constant
*/
if (tp->t_rxtshift == 1 &&
CC_ALGO(tp)->after_timeout != NULL) {
CC_ALGO(tp)->after_timeout(tp);
/*
* CWR notifications are to be sent on new data
* right after Fast Retransmits and ECE
* notification receipts.
*/
if (!TCP_ACC_ECN_ON(tp) && TCP_ECN_ENABLED(tp)) {
tp->ecn_flags |= TE_SENDCWR;
}
}
EXIT_FASTRECOVERY(tp);
/* Exit cwnd non validated phase */
tp->t_flagsext &= ~TF_CWND_NONVALIDATED;
fc_output:
tcp_ccdbg_trace(tp, NULL, TCP_CC_REXMT_TIMEOUT);
(void) tcp_output(tp);
break;
/*
* Persistance timer into zero window.
* Force a byte to be output, if possible.
*/
case TCPT_PERSIST:
tcpstat.tcps_persisttimeo++;
/*
* Hack: if the peer is dead/unreachable, we do not
* time out if the window is closed. After a full
* backoff, drop the connection if the idle time
* (no responses to probes) reaches the maximum
* backoff that we would use if retransmitting.
*
* Drop the connection if we reached the maximum allowed time for
* Zero Window Probes without a non-zero update from the peer.
* See rdar://5805356
*/
if ((tp->t_rxtshift == TCP_MAXRXTSHIFT &&
(idle_time >= tcp_maxpersistidle ||
idle_time >= TCP_REXMTVAL(tp) * tcp_totbackoff)) ||
((tp->t_persist_stop != 0) &&
TSTMP_LEQ(tp->t_persist_stop, tcp_now))) {
TCP_LOG_DROP_PCB(NULL, NULL, tp, false, "persist timeout drop");
tcpstat.tcps_persistdrop++;
soevent(so,
(SO_FILT_HINT_LOCKED | SO_FILT_HINT_TIMEOUT));
tp = tcp_drop(tp, ETIMEDOUT);
break;
}
tcp_setpersist(tp);
tp->t_flagsext |= TF_FORCE;
(void) tcp_output(tp);
tp->t_flagsext &= ~TF_FORCE;
break;
/*
* Keep-alive timer went off; send something
* or drop connection if idle for too long.
*/
case TCPT_KEEP:
#if FLOW_DIVERT
if (tp->t_inpcb->inp_socket->so_flags & SOF_FLOW_DIVERT) {
break;
}
#endif /* FLOW_DIVERT */
tcpstat.tcps_keeptimeo++;
#if MPTCP
/*
* Regular TCP connections do not send keepalives after closing
* MPTCP must not also, after sending Data FINs.
*/
struct mptcb *mp_tp = tptomptp(tp);
if ((tp->t_mpflags & TMPF_MPTCP_TRUE) &&
(tp->t_state > TCPS_ESTABLISHED)) {
goto dropit;
} else if (mp_tp != NULL) {
if ((mptcp_ok_to_keepalive(mp_tp) == 0)) {
goto dropit;
}
}
#endif /* MPTCP */
if (tp->t_state < TCPS_ESTABLISHED) {
goto dropit;
}
if ((always_keepalive ||
(tp->t_inpcb->inp_socket->so_options & SO_KEEPALIVE) ||
(tp->t_flagsext & TF_DETECT_READSTALL) ||
(tp->t_tfo_probe_state == TFO_PROBE_PROBING)) &&
(tp->t_state <= TCPS_CLOSING || tp->t_state == TCPS_FIN_WAIT_2)) {
if (idle_time >= TCP_CONN_KEEPIDLE(tp) + TCP_CONN_MAXIDLE(tp)) {
TCP_LOG_DROP_PCB(NULL, NULL, tp, false,
"keep alive timeout drop");
goto dropit;
}
if (tcp_send_keep_alive(tp)) {
if (tp->t_flagsext & TF_DETECT_READSTALL) {
tp->t_rtimo_probes++;
}
TCP_LOG_KEEP_ALIVE(tp, idle_time);
}
tp->t_timer[TCPT_KEEP] = OFFSET_FROM_START(tp,
TCP_CONN_KEEPINTVL(tp));
} else {
tp->t_timer[TCPT_KEEP] = OFFSET_FROM_START(tp,
TCP_CONN_KEEPIDLE(tp));
}
if (tp->t_flagsext & TF_DETECT_READSTALL) {
struct ifnet *outifp = tp->t_inpcb->inp_last_outifp;
bool reenable_probe = false;
/*
* The keep alive packets sent to detect a read
* stall did not get a response from the
* peer. Generate more keep-alives to confirm this.
* If the number of probes sent reaches the limit,
* generate an event.
*/
if (tp->t_adaptive_rtimo > 0) {
if (tp->t_rtimo_probes > tp->t_adaptive_rtimo) {
/* Generate an event */
soevent(so,
(SO_FILT_HINT_LOCKED |
SO_FILT_HINT_ADAPTIVE_RTIMO));
tcp_keepalive_reset(tp);
} else {
reenable_probe = true;
}
} else if (outifp != NULL &&
(outifp->if_eflags & IFEF_PROBE_CONNECTIVITY) &&
tp->t_rtimo_probes <= TCP_CONNECTIVITY_PROBES_MAX) {
reenable_probe = true;
} else {
tp->t_flagsext &= ~TF_DETECT_READSTALL;
}
if (reenable_probe) {
int ind = min(tp->t_rtimo_probes,
TCP_MAXRXTSHIFT);
tp->t_timer[TCPT_KEEP] = OFFSET_FROM_START(
tp, tcp_backoff[ind] * TCP_REXMTVAL(tp));
}
}
if (tp->t_tfo_probe_state == TFO_PROBE_PROBING) {
int ind;
tp->t_tfo_probes++;
ind = min(tp->t_tfo_probes, TCP_MAXRXTSHIFT);
/*
* We take the minimum among the time set by true
* keepalive (see above) and the backoff'd RTO. That
* way we backoff in case of packet-loss but will never
* timeout slower than regular keepalive due to the
* backing off.
*/
tp->t_timer[TCPT_KEEP] = min(OFFSET_FROM_START(
tp, tcp_backoff[ind] * TCP_REXMTVAL(tp)),
tp->t_timer[TCPT_KEEP]);
} else if (!(tp->t_flagsext & TF_FASTOPEN_FORCE_ENABLE) &&
!(tp->t_tfo_flags & TFO_F_HEURISTIC_DONE) &&
tp->t_tfo_probe_state == TFO_PROBE_WAIT_DATA) {
/* Still no data! Let's assume a TFO-error and err out... */
tcp_heuristic_tfo_middlebox(tp);
so->so_error = ENODATA;
soevent(so,
(SO_FILT_HINT_LOCKED | SO_FILT_HINT_MP_SUB_ERROR));
sorwakeup(so);
tp->t_tfo_stats |= TFO_S_RECV_BLACKHOLE;
tcpstat.tcps_tfo_blackhole++;
}
break;
case TCPT_DELACK:
if (tcp_delack_enabled && (tp->t_flags & TF_DELACK)) {
tp->t_flags &= ~TF_DELACK;
tp->t_timer[TCPT_DELACK] = 0;
tp->t_flags |= TF_ACKNOW;
/*
* If delayed ack timer fired while stretching
* acks, count the number of times the streaming
* detection was not correct. If this exceeds a
* threshold, disable strech ack on this
* connection
*
* Also, go back to acking every other packet.
*/
if ((tp->t_flags & TF_STRETCHACK)) {
if (tp->t_unacksegs > 1 &&
tp->t_unacksegs < maxseg_unacked) {
tp->t_stretchack_delayed++;
}
if (tp->t_stretchack_delayed >
TCP_STRETCHACK_DELAY_THRESHOLD) {
tp->t_flagsext |= TF_DISABLE_STRETCHACK;
/*
* Note the time at which stretch
* ack was disabled automatically
*/
tp->rcv_nostrack_ts = tcp_now;
tcpstat.tcps_nostretchack++;
tp->t_stretchack_delayed = 0;
tp->rcv_nostrack_pkts = 0;
}
tcp_reset_stretch_ack(tp);
}
tp->t_forced_acks = TCP_FORCED_ACKS_COUNT;
/*
* If we are measuring inter packet arrival jitter
* for throttling a connection, this delayed ack
* might be the reason for accumulating some
* jitter. So let's restart the measurement.
*/
CLEAR_IAJ_STATE(tp);
tcpstat.tcps_delack++;
tp->t_stat.delayed_acks_sent++;
(void) tcp_output(tp);
}
break;
#if MPTCP
case TCPT_JACK_RXMT:
if ((tp->t_state == TCPS_ESTABLISHED) &&
(tp->t_mpflags & TMPF_PREESTABLISHED) &&
(tp->t_mpflags & TMPF_JOINED_FLOW)) {
if (++tp->t_mprxtshift > TCP_MAXRXTSHIFT) {
tcpstat.tcps_timeoutdrop++;
soevent(so,
(SO_FILT_HINT_LOCKED |
SO_FILT_HINT_TIMEOUT));
tp = tcp_drop(tp, tp->t_softerror ?
tp->t_softerror : ETIMEDOUT);
break;
}
tcpstat.tcps_join_rxmts++;
tp->t_mpflags |= TMPF_SND_JACK;
tp->t_flags |= TF_ACKNOW;
/*
* No backoff is implemented for simplicity for this
* corner case.
*/
(void) tcp_output(tp);
}
break;
case TCPT_CELLICON:
{
struct mptses *mpte = tptomptp(tp)->mpt_mpte;
tp->t_timer[TCPT_CELLICON] = 0;
if (mpte->mpte_cellicon_increments == 0) {
/* Cell-icon not set by this connection */
break;
}
if (TSTMP_LT(mpte->mpte_last_cellicon_set + MPTCP_CELLICON_TOGGLE_RATE, tcp_now)) {
mptcp_unset_cellicon(mpte, NULL, 1);
}
if (mpte->mpte_cellicon_increments) {
tp->t_timer[TCPT_CELLICON] = OFFSET_FROM_START(tp, MPTCP_CELLICON_TOGGLE_RATE);
}
break;
}
#endif /* MPTCP */
case TCPT_PTO:
{
int32_t ret = 0;
if (!(tp->t_flagsext & TF_IF_PROBING)) {
tp->t_flagsext &= ~(TF_SENT_TLPROBE);
}
/*
* Check if the connection is in the right state to
* send a probe
*/
if ((tp->t_state != TCPS_ESTABLISHED ||
tp->t_rxtshift > 0 ||
tp->snd_max == tp->snd_una ||
!SACK_ENABLED(tp) ||
(tcp_do_better_lr != 1 && !TAILQ_EMPTY(&tp->snd_holes)) ||
IN_FASTRECOVERY(tp)) &&
!(tp->t_flagsext & TF_IF_PROBING)) {
break;
}
/*
* When the interface state is changed explicitly reset the retransmission
* timer state for both SYN and data packets because we do not want to
* wait unnecessarily or timeout too quickly if the link characteristics
* have changed drastically
*/
if (tp->t_flagsext & TF_IF_PROBING) {
tp->t_rxtshift = 0;
if (tp->t_state == TCPS_SYN_SENT) {
tp->t_stat.synrxtshift = tp->t_rxtshift;
}
/*
* Reset to the the default RTO
*/
tp->t_srtt = TCPTV_SRTTBASE;
tp->t_rttvar =
((TCPTV_RTOBASE - TCPTV_SRTTBASE) << TCP_RTTVAR_SHIFT) / 4;
tp->t_rttmin = tp->t_flags & TF_LOCAL ? tcp_TCPTV_MIN :
TCPTV_REXMTMIN;
TCPT_RANGESET(tp->t_rxtcur, TCP_REXMTVAL(tp),
tp->t_rttmin, TCPTV_REXMTMAX, TCP_ADD_REXMTSLOP(tp));
TCP_LOG_RTT_INFO(tp);
}
if (tp->t_state == TCPS_SYN_SENT) {
/*
* The PTO for SYN_SENT reinitializes TCP as if it was a fresh
* connection attempt
*/
tp->snd_nxt = tp->snd_una;
/*
* Note: We overload snd_recover to function also as the
* snd_last variable described in RFC 2582
*/
tp->snd_recover = tp->snd_max;
/*
* Force a segment to be sent.
*/
tp->t_flags |= TF_ACKNOW;
/* If timing a segment in this window, stop the timer */
tp->t_rtttime = 0;
} else {
int32_t snd_len;
/*
* If there is no new data to send or if the
* connection is limited by receive window then
* retransmit the last segment, otherwise send
* new data.
*/
snd_len = min(so->so_snd.sb_cc, tp->snd_wnd)
- (tp->snd_max - tp->snd_una);
if (snd_len > 0) {
tp->snd_nxt = tp->snd_max;
} else {
snd_len = min((tp->snd_max - tp->snd_una),
tp->t_maxseg);
tp->snd_nxt = tp->snd_max - snd_len;
}
}
tcpstat.tcps_pto++;
if (tp->t_flagsext & TF_IF_PROBING) {
tcpstat.tcps_probe_if++;
}
/* If timing a segment in this window, stop the timer */
tp->t_rtttime = 0;
/* Note that tail loss probe is being sent. Exclude IF probe */
if (!(tp->t_flagsext & TF_IF_PROBING)) {
tp->t_flagsext |= TF_SENT_TLPROBE;
tp->t_tlpstart = tcp_now;
}
tp->snd_cwnd += tp->t_maxseg;
/*
* When tail-loss-probe fires, we reset the RTO timer, because
* a probe just got sent, so we are good to push out the timer.
*
* Set to 0 to ensure that tcp_output() will reschedule it
*/
tp->t_timer[TCPT_REXMT] = 0;
ret = tcp_output(tp);
#if (DEBUG || DEVELOPMENT)
if ((tp->t_flagsext & TF_IF_PROBING) &&
((IFNET_IS_COMPANION_LINK(tp->t_inpcb->inp_last_outifp)) ||
tp->t_state == TCPS_SYN_SENT)) {
if (ret == 0 && tcp_probe_if_fix_port > 0 &&
tcp_probe_if_fix_port <= IPPORT_HILASTAUTO) {
tp->t_timer[TCPT_REXMT] = 0;
tcp_set_lotimer_index(tp);
}
os_log(OS_LOG_DEFAULT,
"%s: sent %s probe for %u > %u on interface %s"
" (%u) %s(%d)",
__func__,
tp->t_state == TCPS_SYN_SENT ? "SYN" : "data",
ntohs(tp->t_inpcb->inp_lport),
ntohs(tp->t_inpcb->inp_fport),
if_name(tp->t_inpcb->inp_last_outifp),
tp->t_inpcb->inp_last_outifp->if_index,
ret == 0 ? "succeeded" :"failed", ret);
}
#endif /* DEBUG || DEVELOPMENT */
/*
* When there is data (or a SYN) to send, the above call to
* tcp_output() should have armed either the REXMT or the
* PERSIST timer. If it didn't, something is wrong and this
* connection would idle around forever. Let's make sure that
* at least the REXMT timer is set.
*/
if (tp->t_timer[TCPT_REXMT] == 0 && tp->t_timer[TCPT_PERSIST] == 0 &&
(tp->t_inpcb->inp_socket->so_snd.sb_cc != 0 || tp->t_state == TCPS_SYN_SENT ||
tp->t_state == TCPS_SYN_RECEIVED)) {
tp->t_timer[TCPT_REXMT] =
OFFSET_FROM_START(tp, tp->t_rxtcur);
os_log(OS_LOG_DEFAULT,
"%s: tcp_output() returned %u with retransmission timer disabled "
"for %u > %u in state %d, reset timer to %d",
__func__, ret,
ntohs(tp->t_inpcb->inp_lport),
ntohs(tp->t_inpcb->inp_fport),
tp->t_state,
tp->t_timer[TCPT_REXMT]);
tcp_check_timer_state(tp);
}
tp->snd_cwnd -= tp->t_maxseg;
if (!(tp->t_flagsext & TF_IF_PROBING)) {
tp->t_tlphighrxt = tp->snd_nxt;
}
break;
}
case TCPT_DELAYFR:
tp->t_flagsext &= ~TF_DELAY_RECOVERY;
/*
* Don't do anything if one of the following is true:
* - the connection is already in recovery
* - sequence until snd_recover has been acknowledged.
* - retransmit timeout has fired
*/
if (IN_FASTRECOVERY(tp) ||
SEQ_GEQ(tp->snd_una, tp->snd_recover) ||
tp->t_rxtshift > 0) {
break;
}
VERIFY(SACK_ENABLED(tp));
tcp_rexmt_save_state(tp);
if (CC_ALGO(tp)->pre_fr != NULL) {
CC_ALGO(tp)->pre_fr(tp);
if (!TCP_ACC_ECN_ON(tp) && TCP_ECN_ENABLED(tp)) {
tp->ecn_flags |= TE_SENDCWR;
}
}
ENTER_FASTRECOVERY(tp);
tp->t_timer[TCPT_REXMT] = 0;
tcpstat.tcps_sack_recovery_episode++;
tp->t_sack_recovery_episode++;
tp->sack_newdata = tp->snd_nxt;
tp->snd_cwnd = tp->t_maxseg;
tcp_ccdbg_trace(tp, NULL, TCP_CC_ENTER_FASTRECOVERY);
(void) tcp_output(tp);
break;
dropit:
tcpstat.tcps_keepdrops++;
soevent(so,
(SO_FILT_HINT_LOCKED | SO_FILT_HINT_TIMEOUT));
tp = tcp_drop(tp, ETIMEDOUT);
break;
}
#if TCPDEBUG
if (tp->t_inpcb->inp_socket->so_options & SO_DEBUG) {
tcp_trace(TA_USER, ostate, tp, (void *)0, (struct tcphdr *)0,
PRU_SLOWTIMO);
}
#endif
return tp;
}
/* Remove a timer entry from timer list */
void
tcp_remove_timer(struct tcpcb *tp)
{
struct tcptimerlist *listp = &tcp_timer_list;
socket_lock_assert_owned(tp->t_inpcb->inp_socket);
if (!(TIMER_IS_ON_LIST(tp))) {
return;
}
lck_mtx_lock(&listp->mtx);
/* Check if pcb is on timer list again after acquiring the lock */
if (!(TIMER_IS_ON_LIST(tp))) {
lck_mtx_unlock(&listp->mtx);
return;
}
if (listp->next_te != NULL && listp->next_te == &tp->tentry) {
listp->next_te = LIST_NEXT(&tp->tentry, le);
}
LIST_REMOVE(&tp->tentry, le);
tp->t_flags &= ~(TF_TIMER_ONLIST);
listp->entries--;
tp->tentry.le.le_next = NULL;
tp->tentry.le.le_prev = NULL;
lck_mtx_unlock(&listp->mtx);
}
/*
* Function to check if the timerlist needs to be rescheduled to run
* the timer entry correctly. Basically, this is to check if we can avoid
* taking the list lock.
*/
static boolean_t
need_to_resched_timerlist(u_int32_t runtime, u_int16_t mode)
{
struct tcptimerlist *listp = &tcp_timer_list;
int32_t diff;
/*
* If the list is being processed then the state of the list is
* in flux. In this case always acquire the lock and set the state
* correctly.
*/
if (listp->running) {
return TRUE;
}
if (!listp->scheduled) {
return TRUE;
}
diff = timer_diff(listp->runtime, 0, runtime, 0);
if (diff <= 0) {
/* The list is going to run before this timer */
return FALSE;
} else {
if (mode & TCP_TIMERLIST_10MS_MODE) {
if (diff <= TCP_TIMER_10MS_QUANTUM) {
return FALSE;
}
} else if (mode & TCP_TIMERLIST_100MS_MODE) {
if (diff <= TCP_TIMER_100MS_QUANTUM) {
return FALSE;
}
} else {
if (diff <= TCP_TIMER_500MS_QUANTUM) {
return FALSE;
}
}
}
return TRUE;
}
void
tcp_sched_timerlist(uint32_t offset)
{
uint64_t deadline = 0;
struct tcptimerlist *listp = &tcp_timer_list;
LCK_MTX_ASSERT(&listp->mtx, LCK_MTX_ASSERT_OWNED);
offset = min(offset, TCP_TIMERLIST_MAX_OFFSET);
listp->runtime = tcp_now + offset;
listp->schedtime = tcp_now;
if (listp->runtime == 0) {
listp->runtime++;
offset++;
}
clock_interval_to_deadline(offset, USEC_PER_SEC, &deadline);
thread_call_enter_delayed(listp->call, deadline);
listp->scheduled = TRUE;
}
/*
* Function to run the timers for a connection.
*
* Returns the offset of next timer to be run for this connection which
* can be used to reschedule the timerlist.
*
* te_mode is an out parameter that indicates the modes of active
* timers for this connection.
*/
u_int32_t
tcp_run_conn_timer(struct tcpcb *tp, u_int16_t *te_mode,
u_int16_t probe_if_index)
{
struct socket *so;
u_int16_t i = 0, index = TCPT_NONE, lo_index = TCPT_NONE;
u_int32_t timer_val, offset = 0, lo_timer = 0;
int32_t diff;
boolean_t needtorun[TCPT_NTIMERS];
int count = 0;
VERIFY(tp != NULL);
bzero(needtorun, sizeof(needtorun));
*te_mode = 0;
socket_lock(tp->t_inpcb->inp_socket, 1);
so = tp->t_inpcb->inp_socket;
/* Release the want count on inp */
if (in_pcb_checkstate(tp->t_inpcb, WNT_RELEASE, 1)
== WNT_STOPUSING) {
if (TIMER_IS_ON_LIST(tp)) {
tcp_remove_timer(tp);
}
/* Looks like the TCP connection got closed while we
* were waiting for the lock.. Done
*/
goto done;
}
/*
* If this connection is over an interface that needs to
* be probed, send probe packets to reinitiate communication.
*/
if (TCP_IF_STATE_CHANGED(tp, probe_if_index)) {
tp->t_flagsext |= TF_IF_PROBING;
tcp_timers(tp, TCPT_PTO);
tp->t_timer[TCPT_PTO] = 0;
tp->t_flagsext &= ~TF_IF_PROBING;
}
/*
* Since the timer thread needs to wait for tcp lock, it may race
* with another thread that can cancel or reschedule the timer
* that is about to run. Check if we need to run anything.
*/
if ((index = tp->tentry.index) == TCPT_NONE) {
goto done;
}
timer_val = tp->t_timer[index];
diff = timer_diff(tp->tentry.runtime, 0, tcp_now, 0);
if (diff > 0) {
if (tp->tentry.index != TCPT_NONE) {
offset = diff;
*(te_mode) = tp->tentry.mode;
}
goto done;
}
tp->t_timer[index] = 0;
if (timer_val > 0) {
tp = tcp_timers(tp, index);
if (tp == NULL) {
goto done;
}
}
/*
* Check if there are any other timers that need to be run.
* While doing it, adjust the timer values wrt tcp_now.
*/
tp->tentry.mode = 0;
for (i = 0; i < TCPT_NTIMERS; ++i) {
if (tp->t_timer[i] != 0) {
diff = timer_diff(tp->tentry.timer_start,
tp->t_timer[i], tcp_now, 0);
if (diff <= 0) {
needtorun[i] = TRUE;
count++;
} else {
tp->t_timer[i] = diff;
needtorun[i] = FALSE;
if (lo_timer == 0 || diff < lo_timer) {
lo_timer = diff;
lo_index = i;
}
TCP_SET_TIMER_MODE(tp->tentry.mode, i);
}
}
}
tp->tentry.timer_start = tcp_now;
tp->tentry.index = lo_index;
VERIFY(tp->tentry.index == TCPT_NONE || tp->tentry.mode > 0);
if (tp->tentry.index != TCPT_NONE) {
tp->tentry.runtime = tp->tentry.timer_start +
tp->t_timer[tp->tentry.index];
if (tp->tentry.runtime == 0) {
tp->tentry.runtime++;
}
}
if (count > 0) {
/* run any other timers outstanding at this time. */
for (i = 0; i < TCPT_NTIMERS; ++i) {
if (needtorun[i]) {
tp->t_timer[i] = 0;
tp = tcp_timers(tp, i);
if (tp == NULL) {
offset = 0;
*(te_mode) = 0;
goto done;
}
}
}
tcp_set_lotimer_index(tp);
}
if (tp->tentry.index < TCPT_NONE) {
offset = tp->t_timer[tp->tentry.index];
*(te_mode) = tp->tentry.mode;
}
done:
if (tp != NULL && tp->tentry.index == TCPT_NONE) {
tcp_remove_timer(tp);
offset = 0;
}
socket_unlock(so, 1);
return offset;
}
void
tcp_run_timerlist(void * arg1, void * arg2)
{
#pragma unused(arg1, arg2)
struct tcptimerentry *te, *next_te;
struct tcptimerlist *listp = &tcp_timer_list;
struct tcpcb *tp;
uint32_t next_timer = 0; /* offset of the next timer on the list */
u_int16_t te_mode = 0; /* modes of all active timers in a tcpcb */
u_int16_t list_mode = 0; /* cumulative of modes of all tcpcbs */
uint32_t active_count = 0;
calculate_tcp_clock();
lck_mtx_lock(&listp->mtx);
int32_t drift = tcp_now - listp->runtime;
if (drift <= 1) {
tcpstat.tcps_timer_drift_le_1_ms++;
} else if (drift <= 10) {
tcpstat.tcps_timer_drift_le_10_ms++;
} else if (drift <= 20) {
tcpstat.tcps_timer_drift_le_20_ms++;
} else if (drift <= 50) {
tcpstat.tcps_timer_drift_le_50_ms++;
} else if (drift <= 100) {
tcpstat.tcps_timer_drift_le_100_ms++;
} else if (drift <= 200) {
tcpstat.tcps_timer_drift_le_200_ms++;
} else if (drift <= 500) {
tcpstat.tcps_timer_drift_le_500_ms++;
} else if (drift <= 1000) {
tcpstat.tcps_timer_drift_le_1000_ms++;
} else {
tcpstat.tcps_timer_drift_gt_1000_ms++;
}
listp->running = TRUE;
LIST_FOREACH_SAFE(te, &listp->lhead, le, next_te) {
uint32_t offset = 0;
uint32_t runtime = te->runtime;
tp = TIMERENTRY_TO_TP(te);
/*
* An interface probe may need to happen before the previously scheduled runtime
*/
if (te->index < TCPT_NONE && TSTMP_GT(runtime, tcp_now) &&
!TCP_IF_STATE_CHANGED(tp, listp->probe_if_index)) {
offset = timer_diff(runtime, 0, tcp_now, 0);
if (next_timer == 0 || offset < next_timer) {
next_timer = offset;
}
list_mode |= te->mode;
continue;
}
/*
* Acquire an inp wantcnt on the inpcb so that the socket
* won't get detached even if tcp_close is called
*/
if (in_pcb_checkstate(tp->t_inpcb, WNT_ACQUIRE, 0)
== WNT_STOPUSING) {
/*
* Some how this pcb went into dead state while
* on the timer list, just take it off the list.
* Since the timer list entry pointers are
* protected by the timer list lock, we can
* do it here without the socket lock.
*/
if (TIMER_IS_ON_LIST(tp)) {
tp->t_flags &= ~(TF_TIMER_ONLIST);
LIST_REMOVE(&tp->tentry, le);
listp->entries--;
tp->tentry.le.le_next = NULL;
tp->tentry.le.le_prev = NULL;
}
continue;
}
active_count++;
/*
* Store the next timerentry pointer before releasing the
* list lock. If that entry has to be removed when we
* release the lock, this pointer will be updated to the
* element after that.
*/
listp->next_te = next_te;
VERIFY_NEXT_LINK(&tp->tentry, le);
VERIFY_PREV_LINK(&tp->tentry, le);
lck_mtx_unlock(&listp->mtx);
offset = tcp_run_conn_timer(tp, &te_mode,
listp->probe_if_index);
lck_mtx_lock(&listp->mtx);
next_te = listp->next_te;
listp->next_te = NULL;
if (offset > 0 && te_mode != 0) {
list_mode |= te_mode;
if (next_timer == 0 || offset < next_timer) {
next_timer = offset;
}
}
}
if (!LIST_EMPTY(&listp->lhead)) {
uint32_t next_mode = 0;
if ((list_mode & TCP_TIMERLIST_10MS_MODE) ||
(listp->pref_mode & TCP_TIMERLIST_10MS_MODE)) {
next_mode = TCP_TIMERLIST_10MS_MODE;
} else if ((list_mode & TCP_TIMERLIST_100MS_MODE) ||
(listp->pref_mode & TCP_TIMERLIST_100MS_MODE)) {
next_mode = TCP_TIMERLIST_100MS_MODE;
} else {
next_mode = TCP_TIMERLIST_500MS_MODE;
}
if (next_mode != TCP_TIMERLIST_500MS_MODE) {
listp->idleruns = 0;
} else {
/*
* the next required mode is slow mode, but if
* the last one was a faster mode and we did not
* have enough idle runs, repeat the last mode.
*
* We try to keep the timer list in fast mode for
* some idle time in expectation of new data.
*/
if (listp->mode != next_mode &&
listp->idleruns < timer_fastmode_idlemax) {
listp->idleruns++;
next_mode = listp->mode;
next_timer = TCP_TIMER_100MS_QUANTUM;
} else {
listp->idleruns = 0;
}
}
listp->mode = next_mode;
if (listp->pref_offset != 0) {
next_timer = min(listp->pref_offset, next_timer);
}
if (listp->mode == TCP_TIMERLIST_500MS_MODE) {
next_timer = max(next_timer,
TCP_TIMER_500MS_QUANTUM);
}
tcp_sched_timerlist(next_timer);
} else {
/*
* No need to reschedule this timer, but always run
* periodically at a much higher granularity.
*/
tcp_sched_timerlist(TCP_TIMERLIST_MAX_OFFSET);
}
listp->running = FALSE;
listp->pref_mode = 0;
listp->pref_offset = 0;
listp->probe_if_index = 0;
lck_mtx_unlock(&listp->mtx);
}
/*
* Function to check if the timerlist needs to be rescheduled to run this
* connection's timers correctly.
*/
void
tcp_sched_timers(struct tcpcb *tp)
{
struct tcptimerentry *te = &tp->tentry;
u_int16_t index = te->index;
u_int16_t mode = te->mode;
struct tcptimerlist *listp = &tcp_timer_list;
int32_t offset = 0;
boolean_t list_locked = FALSE;
if (tp->t_inpcb->inp_state == INPCB_STATE_DEAD) {
/* Just return without adding the dead pcb to the list */
if (TIMER_IS_ON_LIST(tp)) {
tcp_remove_timer(tp);
}
return;
}
if (index == TCPT_NONE) {
/* Nothing to run */
tcp_remove_timer(tp);
return;
}
/*
* compute the offset at which the next timer for this connection
* has to run.
*/
offset = timer_diff(te->runtime, 0, tcp_now, 0);
if (offset <= 0) {
offset = 1;
tcp_timer_advanced++;
}
if (!TIMER_IS_ON_LIST(tp)) {
if (!list_locked) {
lck_mtx_lock(&listp->mtx);
list_locked = TRUE;
}
if (!TIMER_IS_ON_LIST(tp)) {
LIST_INSERT_HEAD(&listp->lhead, te, le);
tp->t_flags |= TF_TIMER_ONLIST;
listp->entries++;
if (listp->entries > listp->maxentries) {
listp->maxentries = listp->entries;
}
/* if the list is not scheduled, just schedule it */
if (!listp->scheduled) {
goto schedule;
}
}
}
/*
* Timer entry is currently on the list, check if the list needs
* to be rescheduled.
*/
if (need_to_resched_timerlist(te->runtime, mode)) {
tcp_resched_timerlist++;
if (!list_locked) {
lck_mtx_lock(&listp->mtx);
list_locked = TRUE;
}
VERIFY_NEXT_LINK(te, le);
VERIFY_PREV_LINK(te, le);
if (listp->running) {
listp->pref_mode |= mode;
if (listp->pref_offset == 0 ||
offset < listp->pref_offset) {
listp->pref_offset = offset;
}
} else {
/*
* The list could have got rescheduled while
* this thread was waiting for the lock
*/
if (listp->scheduled) {
int32_t diff;
diff = timer_diff(listp->runtime, 0,
tcp_now, offset);
if (diff <= 0) {
goto done;
} else {
goto schedule;
}
} else {
goto schedule;
}
}
}
goto done;
schedule:
/*
* Since a connection with timers is getting scheduled, the timer
* list moves from idle to active state and that is why idlegen is
* reset
*/
if (mode & TCP_TIMERLIST_10MS_MODE) {
listp->mode = TCP_TIMERLIST_10MS_MODE;
listp->idleruns = 0;
offset = min(offset, TCP_TIMER_10MS_QUANTUM);
} else if (mode & TCP_TIMERLIST_100MS_MODE) {
if (listp->mode > TCP_TIMERLIST_100MS_MODE) {
listp->mode = TCP_TIMERLIST_100MS_MODE;
}
listp->idleruns = 0;
offset = min(offset, TCP_TIMER_100MS_QUANTUM);
}
tcp_sched_timerlist(offset);
done:
if (list_locked) {
lck_mtx_unlock(&listp->mtx);
}
return;
}
static inline void
tcp_set_lotimer_index(struct tcpcb *tp)
{
uint16_t i, lo_index = TCPT_NONE, mode = 0;
uint32_t lo_timer = 0;
for (i = 0; i < TCPT_NTIMERS; ++i) {
if (tp->t_timer[i] != 0) {
TCP_SET_TIMER_MODE(mode, i);
if (lo_timer == 0 || tp->t_timer[i] < lo_timer) {
lo_timer = tp->t_timer[i];
lo_index = i;
}
}
}
tp->tentry.index = lo_index;
tp->tentry.mode = mode;
VERIFY(tp->tentry.index == TCPT_NONE || tp->tentry.mode > 0);
if (tp->tentry.index != TCPT_NONE) {
tp->tentry.runtime = tp->tentry.timer_start
+ tp->t_timer[tp->tentry.index];
if (tp->tentry.runtime == 0) {
tp->tentry.runtime++;
}
}
}
void
tcp_check_timer_state(struct tcpcb *tp)
{
socket_lock_assert_owned(tp->t_inpcb->inp_socket);
if (tp->t_inpcb->inp_flags2 & INP2_TIMEWAIT) {
return;
}
tcp_set_lotimer_index(tp);
tcp_sched_timers(tp);
return;
}
static inline void
tcp_cumulative_stat(u_int32_t cur, u_int32_t *prev, u_int32_t *dest)
{
/* handle wrap around */
int32_t diff = (int32_t) (cur - *prev);
if (diff > 0) {
*dest = diff;
} else {
*dest = 0;
}
*prev = cur;
return;
}
static inline void
tcp_cumulative_stat64(u_int64_t cur, u_int64_t *prev, u_int64_t *dest)
{
/* handle wrap around */
int64_t diff = (int64_t) (cur - *prev);
if (diff > 0) {
*dest = diff;
} else {
*dest = 0;
}
*prev = cur;
return;
}
__private_extern__ void
tcp_report_stats(void)
{
struct nstat_sysinfo_data data;
struct sockaddr_in dst;
struct sockaddr_in6 dst6;
struct rtentry *rt = NULL;
static struct tcp_last_report_stats prev;
u_int64_t var, uptime;
#define stat data.u.tcp_stats
if (((uptime = net_uptime()) - tcp_last_report_time) <
tcp_report_stats_interval) {
return;
}
tcp_last_report_time = uptime;
bzero(&data, sizeof(data));
data.flags = NSTAT_SYSINFO_TCP_STATS;
SOCKADDR_ZERO(&dst, sizeof(dst));
dst.sin_len = sizeof(dst);
dst.sin_family = AF_INET;
/* ipv4 avg rtt */
lck_mtx_lock(rnh_lock);
rt = rt_lookup(TRUE, SA(&dst), NULL,
rt_tables[AF_INET], IFSCOPE_NONE);
lck_mtx_unlock(rnh_lock);
if (rt != NULL) {
RT_LOCK(rt);
if (rt_primary_default(rt, rt_key(rt)) &&
rt->rt_stats != NULL) {
stat.ipv4_avgrtt = rt->rt_stats->nstat_avg_rtt;
}
RT_UNLOCK(rt);
rtfree(rt);
rt = NULL;
}
/* ipv6 avg rtt */
SOCKADDR_ZERO(&dst6, sizeof(dst6));
dst6.sin6_len = sizeof(dst6);
dst6.sin6_family = AF_INET6;
lck_mtx_lock(rnh_lock);
rt = rt_lookup(TRUE, SA(&dst6), NULL,
rt_tables[AF_INET6], IFSCOPE_NONE);
lck_mtx_unlock(rnh_lock);
if (rt != NULL) {
RT_LOCK(rt);
if (rt_primary_default(rt, rt_key(rt)) &&
rt->rt_stats != NULL) {
stat.ipv6_avgrtt = rt->rt_stats->nstat_avg_rtt;
}
RT_UNLOCK(rt);
rtfree(rt);
rt = NULL;
}
/* send packet loss rate, shift by 10 for precision */
if (tcpstat.tcps_sndpack > 0 && tcpstat.tcps_sndrexmitpack > 0) {
var = tcpstat.tcps_sndrexmitpack << 10;
stat.send_plr = (uint32_t)((var * 100) / tcpstat.tcps_sndpack);
}
/* recv packet loss rate, shift by 10 for precision */
if (tcpstat.tcps_rcvpack > 0 && tcpstat.tcps_recovered_pkts > 0) {
var = tcpstat.tcps_recovered_pkts << 10;
stat.recv_plr = (uint32_t)((var * 100) / tcpstat.tcps_rcvpack);
}
/* RTO after tail loss, shift by 10 for precision */
if (tcpstat.tcps_sndrexmitpack > 0
&& tcpstat.tcps_tailloss_rto > 0) {
var = tcpstat.tcps_tailloss_rto << 10;
stat.send_tlrto_rate =
(uint32_t)((var * 100) / tcpstat.tcps_sndrexmitpack);
}
/* packet reordering */
if (tcpstat.tcps_sndpack > 0 && tcpstat.tcps_reordered_pkts > 0) {
var = tcpstat.tcps_reordered_pkts << 10;
stat.send_reorder_rate =
(uint32_t)((var * 100) / tcpstat.tcps_sndpack);
}
if (tcp_ecn_outbound == 1) {
stat.ecn_client_enabled = 1;
}
if (tcp_ecn_inbound == 1) {
stat.ecn_server_enabled = 1;
}
tcp_cumulative_stat(tcpstat.tcps_connattempt,
&prev.tcps_connattempt, &stat.connection_attempts);
tcp_cumulative_stat(tcpstat.tcps_accepts,
&prev.tcps_accepts, &stat.connection_accepts);
tcp_cumulative_stat(tcpstat.tcps_ecn_client_setup,
&prev.tcps_ecn_client_setup, &stat.ecn_client_setup);
tcp_cumulative_stat(tcpstat.tcps_ecn_server_setup,
&prev.tcps_ecn_server_setup, &stat.ecn_server_setup);
tcp_cumulative_stat(tcpstat.tcps_ecn_client_success,
&prev.tcps_ecn_client_success, &stat.ecn_client_success);
tcp_cumulative_stat(tcpstat.tcps_ecn_server_success,
&prev.tcps_ecn_server_success, &stat.ecn_server_success);
tcp_cumulative_stat(tcpstat.tcps_ecn_not_supported,
&prev.tcps_ecn_not_supported, &stat.ecn_not_supported);
tcp_cumulative_stat(tcpstat.tcps_ecn_lost_syn,
&prev.tcps_ecn_lost_syn, &stat.ecn_lost_syn);
tcp_cumulative_stat(tcpstat.tcps_ecn_lost_synack,
&prev.tcps_ecn_lost_synack, &stat.ecn_lost_synack);
tcp_cumulative_stat(tcpstat.tcps_ecn_recv_ce,
&prev.tcps_ecn_recv_ce, &stat.ecn_recv_ce);
tcp_cumulative_stat(tcpstat.tcps_ecn_recv_ece,
&prev.tcps_ecn_recv_ece, &stat.ecn_recv_ece);
tcp_cumulative_stat(tcpstat.tcps_ecn_recv_ece,
&prev.tcps_ecn_recv_ece, &stat.ecn_recv_ece);
tcp_cumulative_stat(tcpstat.tcps_ecn_sent_ece,
&prev.tcps_ecn_sent_ece, &stat.ecn_sent_ece);
tcp_cumulative_stat(tcpstat.tcps_ecn_sent_ece,
&prev.tcps_ecn_sent_ece, &stat.ecn_sent_ece);
tcp_cumulative_stat(tcpstat.tcps_ecn_conn_recv_ce,
&prev.tcps_ecn_conn_recv_ce, &stat.ecn_conn_recv_ce);
tcp_cumulative_stat(tcpstat.tcps_ecn_conn_recv_ece,
&prev.tcps_ecn_conn_recv_ece, &stat.ecn_conn_recv_ece);
tcp_cumulative_stat(tcpstat.tcps_ecn_conn_plnoce,
&prev.tcps_ecn_conn_plnoce, &stat.ecn_conn_plnoce);
tcp_cumulative_stat(tcpstat.tcps_ecn_conn_pl_ce,
&prev.tcps_ecn_conn_pl_ce, &stat.ecn_conn_pl_ce);
tcp_cumulative_stat(tcpstat.tcps_ecn_conn_nopl_ce,
&prev.tcps_ecn_conn_nopl_ce, &stat.ecn_conn_nopl_ce);
tcp_cumulative_stat(tcpstat.tcps_ecn_fallback_synloss,
&prev.tcps_ecn_fallback_synloss, &stat.ecn_fallback_synloss);
tcp_cumulative_stat(tcpstat.tcps_ecn_fallback_reorder,
&prev.tcps_ecn_fallback_reorder, &stat.ecn_fallback_reorder);
tcp_cumulative_stat(tcpstat.tcps_ecn_fallback_ce,
&prev.tcps_ecn_fallback_ce, &stat.ecn_fallback_ce);
tcp_cumulative_stat(tcpstat.tcps_tfo_syn_data_rcv,
&prev.tcps_tfo_syn_data_rcv, &stat.tfo_syn_data_rcv);
tcp_cumulative_stat(tcpstat.tcps_tfo_cookie_req_rcv,
&prev.tcps_tfo_cookie_req_rcv, &stat.tfo_cookie_req_rcv);
tcp_cumulative_stat(tcpstat.tcps_tfo_cookie_sent,
&prev.tcps_tfo_cookie_sent, &stat.tfo_cookie_sent);
tcp_cumulative_stat(tcpstat.tcps_tfo_cookie_invalid,
&prev.tcps_tfo_cookie_invalid, &stat.tfo_cookie_invalid);
tcp_cumulative_stat(tcpstat.tcps_tfo_cookie_req,
&prev.tcps_tfo_cookie_req, &stat.tfo_cookie_req);
tcp_cumulative_stat(tcpstat.tcps_tfo_cookie_rcv,
&prev.tcps_tfo_cookie_rcv, &stat.tfo_cookie_rcv);
tcp_cumulative_stat(tcpstat.tcps_tfo_syn_data_sent,
&prev.tcps_tfo_syn_data_sent, &stat.tfo_syn_data_sent);
tcp_cumulative_stat(tcpstat.tcps_tfo_syn_data_acked,
&prev.tcps_tfo_syn_data_acked, &stat.tfo_syn_data_acked);
tcp_cumulative_stat(tcpstat.tcps_tfo_syn_loss,
&prev.tcps_tfo_syn_loss, &stat.tfo_syn_loss);
tcp_cumulative_stat(tcpstat.tcps_tfo_blackhole,
&prev.tcps_tfo_blackhole, &stat.tfo_blackhole);
tcp_cumulative_stat(tcpstat.tcps_tfo_cookie_wrong,
&prev.tcps_tfo_cookie_wrong, &stat.tfo_cookie_wrong);
tcp_cumulative_stat(tcpstat.tcps_tfo_no_cookie_rcv,
&prev.tcps_tfo_no_cookie_rcv, &stat.tfo_no_cookie_rcv);
tcp_cumulative_stat(tcpstat.tcps_tfo_heuristics_disable,
&prev.tcps_tfo_heuristics_disable, &stat.tfo_heuristics_disable);
tcp_cumulative_stat(tcpstat.tcps_tfo_sndblackhole,
&prev.tcps_tfo_sndblackhole, &stat.tfo_sndblackhole);
tcp_cumulative_stat(tcpstat.tcps_mptcp_handover_attempt,
&prev.tcps_mptcp_handover_attempt, &stat.mptcp_handover_attempt);
tcp_cumulative_stat(tcpstat.tcps_mptcp_interactive_attempt,
&prev.tcps_mptcp_interactive_attempt, &stat.mptcp_interactive_attempt);
tcp_cumulative_stat(tcpstat.tcps_mptcp_aggregate_attempt,
&prev.tcps_mptcp_aggregate_attempt, &stat.mptcp_aggregate_attempt);
tcp_cumulative_stat(tcpstat.tcps_mptcp_fp_handover_attempt,
&prev.tcps_mptcp_fp_handover_attempt, &stat.mptcp_fp_handover_attempt);
tcp_cumulative_stat(tcpstat.tcps_mptcp_fp_interactive_attempt,
&prev.tcps_mptcp_fp_interactive_attempt, &stat.mptcp_fp_interactive_attempt);
tcp_cumulative_stat(tcpstat.tcps_mptcp_fp_aggregate_attempt,
&prev.tcps_mptcp_fp_aggregate_attempt, &stat.mptcp_fp_aggregate_attempt);
tcp_cumulative_stat(tcpstat.tcps_mptcp_heuristic_fallback,
&prev.tcps_mptcp_heuristic_fallback, &stat.mptcp_heuristic_fallback);
tcp_cumulative_stat(tcpstat.tcps_mptcp_fp_heuristic_fallback,
&prev.tcps_mptcp_fp_heuristic_fallback, &stat.mptcp_fp_heuristic_fallback);
tcp_cumulative_stat(tcpstat.tcps_mptcp_handover_success_wifi,
&prev.tcps_mptcp_handover_success_wifi, &stat.mptcp_handover_success_wifi);
tcp_cumulative_stat(tcpstat.tcps_mptcp_handover_success_cell,
&prev.tcps_mptcp_handover_success_cell, &stat.mptcp_handover_success_cell);
tcp_cumulative_stat(tcpstat.tcps_mptcp_interactive_success,
&prev.tcps_mptcp_interactive_success, &stat.mptcp_interactive_success);
tcp_cumulative_stat(tcpstat.tcps_mptcp_aggregate_success,
&prev.tcps_mptcp_aggregate_success, &stat.mptcp_aggregate_success);
tcp_cumulative_stat(tcpstat.tcps_mptcp_fp_handover_success_wifi,
&prev.tcps_mptcp_fp_handover_success_wifi, &stat.mptcp_fp_handover_success_wifi);
tcp_cumulative_stat(tcpstat.tcps_mptcp_fp_handover_success_cell,
&prev.tcps_mptcp_fp_handover_success_cell, &stat.mptcp_fp_handover_success_cell);
tcp_cumulative_stat(tcpstat.tcps_mptcp_fp_interactive_success,
&prev.tcps_mptcp_fp_interactive_success, &stat.mptcp_fp_interactive_success);
tcp_cumulative_stat(tcpstat.tcps_mptcp_fp_aggregate_success,
&prev.tcps_mptcp_fp_aggregate_success, &stat.mptcp_fp_aggregate_success);
tcp_cumulative_stat(tcpstat.tcps_mptcp_handover_cell_from_wifi,
&prev.tcps_mptcp_handover_cell_from_wifi, &stat.mptcp_handover_cell_from_wifi);
tcp_cumulative_stat(tcpstat.tcps_mptcp_handover_wifi_from_cell,
&prev.tcps_mptcp_handover_wifi_from_cell, &stat.mptcp_handover_wifi_from_cell);
tcp_cumulative_stat(tcpstat.tcps_mptcp_interactive_cell_from_wifi,
&prev.tcps_mptcp_interactive_cell_from_wifi, &stat.mptcp_interactive_cell_from_wifi);
tcp_cumulative_stat64(tcpstat.tcps_mptcp_handover_cell_bytes,
&prev.tcps_mptcp_handover_cell_bytes, &stat.mptcp_handover_cell_bytes);
tcp_cumulative_stat64(tcpstat.tcps_mptcp_interactive_cell_bytes,
&prev.tcps_mptcp_interactive_cell_bytes, &stat.mptcp_interactive_cell_bytes);
tcp_cumulative_stat64(tcpstat.tcps_mptcp_aggregate_cell_bytes,
&prev.tcps_mptcp_aggregate_cell_bytes, &stat.mptcp_aggregate_cell_bytes);
tcp_cumulative_stat64(tcpstat.tcps_mptcp_handover_all_bytes,
&prev.tcps_mptcp_handover_all_bytes, &stat.mptcp_handover_all_bytes);
tcp_cumulative_stat64(tcpstat.tcps_mptcp_interactive_all_bytes,
&prev.tcps_mptcp_interactive_all_bytes, &stat.mptcp_interactive_all_bytes);
tcp_cumulative_stat64(tcpstat.tcps_mptcp_aggregate_all_bytes,
&prev.tcps_mptcp_aggregate_all_bytes, &stat.mptcp_aggregate_all_bytes);
tcp_cumulative_stat(tcpstat.tcps_mptcp_back_to_wifi,
&prev.tcps_mptcp_back_to_wifi, &stat.mptcp_back_to_wifi);
tcp_cumulative_stat(tcpstat.tcps_mptcp_wifi_proxy,
&prev.tcps_mptcp_wifi_proxy, &stat.mptcp_wifi_proxy);
tcp_cumulative_stat(tcpstat.tcps_mptcp_cell_proxy,
&prev.tcps_mptcp_cell_proxy, &stat.mptcp_cell_proxy);
tcp_cumulative_stat(tcpstat.tcps_mptcp_triggered_cell,
&prev.tcps_mptcp_triggered_cell, &stat.mptcp_triggered_cell);
nstat_sysinfo_send_data(&data);
#undef stat
}
void
tcp_interface_send_probe(u_int16_t probe_if_index)
{
int32_t offset = 0;
struct tcptimerlist *listp = &tcp_timer_list;
/* Make sure TCP clock is up to date */
calculate_tcp_clock();
lck_mtx_lock(&listp->mtx);
if (listp->probe_if_index > 0 && listp->probe_if_index != probe_if_index) {
tcpstat.tcps_probe_if_conflict++;
os_log(OS_LOG_DEFAULT,
"%s: probe_if_index %u conflicts with %u, tcps_probe_if_conflict %u\n",
__func__, probe_if_index, listp->probe_if_index,
tcpstat.tcps_probe_if_conflict);
goto done;
}
listp->probe_if_index = probe_if_index;
if (listp->running) {
os_log(OS_LOG_DEFAULT, "%s: timer list already running for if_index %u\n",
__func__, probe_if_index);
goto done;
}
/*
* Reschedule the timerlist to run within the next 10ms, which is
* the fastest that we can do.
*/
offset = TCP_TIMER_10MS_QUANTUM;
if (listp->scheduled) {
int32_t diff;
diff = timer_diff(listp->runtime, 0, tcp_now, offset);
if (diff <= 0) {
/* The timer will fire sooner than what's needed */
os_log(OS_LOG_DEFAULT,
"%s: timer will fire sooner than needed for if_index %u\n",
__func__, probe_if_index);
goto done;
}
}
listp->mode = TCP_TIMERLIST_10MS_MODE;
listp->idleruns = 0;
tcp_sched_timerlist(offset);
done:
lck_mtx_unlock(&listp->mtx);
return;
}
/*
* Enable read probes on this connection, if:
* - it is in established state
* - doesn't have any data outstanding
* - the outgoing ifp matches
* - we have not already sent any read probes
*/
static void
tcp_enable_read_probe(struct tcpcb *tp, struct ifnet *ifp)
{
if (tp->t_state == TCPS_ESTABLISHED &&
tp->snd_max == tp->snd_una &&
tp->t_inpcb->inp_last_outifp == ifp &&
!(tp->t_flagsext & TF_DETECT_READSTALL) &&
tp->t_rtimo_probes == 0) {
tp->t_flagsext |= TF_DETECT_READSTALL;
tp->t_rtimo_probes = 0;
tp->t_timer[TCPT_KEEP] = OFFSET_FROM_START(tp,
TCP_TIMER_10MS_QUANTUM);
if (tp->tentry.index == TCPT_NONE) {
tp->tentry.index = TCPT_KEEP;
tp->tentry.runtime = tcp_now +
TCP_TIMER_10MS_QUANTUM;
} else {
int32_t diff = 0;
/* Reset runtime to be in next 10ms */
diff = timer_diff(tp->tentry.runtime, 0,
tcp_now, TCP_TIMER_10MS_QUANTUM);
if (diff > 0) {
tp->tentry.index = TCPT_KEEP;
tp->tentry.runtime = tcp_now +
TCP_TIMER_10MS_QUANTUM;
if (tp->tentry.runtime == 0) {
tp->tentry.runtime++;
}
}
}
}
}
/*
* Disable read probe and reset the keep alive timer
*/
static void
tcp_disable_read_probe(struct tcpcb *tp)
{
if (tp->t_adaptive_rtimo == 0 &&
((tp->t_flagsext & TF_DETECT_READSTALL) ||
tp->t_rtimo_probes > 0)) {
tcp_keepalive_reset(tp);
if (tp->t_mpsub) {
mptcp_reset_keepalive(tp);
}
}
}
/*
* Reschedule the tcp timerlist in the next 10ms to re-enable read/write
* probes on connections going over a particular interface.
*/
void
tcp_probe_connectivity(struct ifnet *ifp, u_int32_t enable)
{
int32_t offset;
struct tcptimerlist *listp = &tcp_timer_list;
struct inpcbinfo *pcbinfo = &tcbinfo;
struct inpcb *inp, *nxt;
if (ifp == NULL) {
return;
}
/* update clock */
calculate_tcp_clock();
/*
* Enable keep alive timer on all connections that are
* active/established on this interface.
*/
lck_rw_lock_shared(&pcbinfo->ipi_lock);
LIST_FOREACH_SAFE(inp, pcbinfo->ipi_listhead, inp_list, nxt) {
struct tcpcb *tp = NULL;
if (in_pcb_checkstate(inp, WNT_ACQUIRE, 0) ==
WNT_STOPUSING) {
continue;
}
/* Acquire lock to look at the state of the connection */
socket_lock(inp->inp_socket, 1);
/* Release the want count */
if (inp->inp_ppcb == NULL ||
(in_pcb_checkstate(inp, WNT_RELEASE, 1) == WNT_STOPUSING)) {
socket_unlock(inp->inp_socket, 1);
continue;
}
tp = intotcpcb(inp);
if (enable) {
tcp_enable_read_probe(tp, ifp);
} else {
tcp_disable_read_probe(tp);
}
socket_unlock(inp->inp_socket, 1);
}
lck_rw_done(&pcbinfo->ipi_lock);
lck_mtx_lock(&listp->mtx);
if (listp->running) {
listp->pref_mode |= TCP_TIMERLIST_10MS_MODE;
goto done;
}
/* Reschedule within the next 10ms */
offset = TCP_TIMER_10MS_QUANTUM;
if (listp->scheduled) {
int32_t diff;
diff = timer_diff(listp->runtime, 0, tcp_now, offset);
if (diff <= 0) {
/* The timer will fire sooner than what's needed */
goto done;
}
}
listp->mode = TCP_TIMERLIST_10MS_MODE;
listp->idleruns = 0;
tcp_sched_timerlist(offset);
done:
lck_mtx_unlock(&listp->mtx);
return;
}
inline void
tcp_update_mss_core(struct tcpcb *tp, struct ifnet *ifp)
{
struct if_cellular_status_v1 *ifsr;
u_int32_t optlen;
ifsr = &ifp->if_link_status->ifsr_u.ifsr_cell.if_cell_u.if_status_v1;
if (ifsr->valid_bitmask & IF_CELL_UL_MSS_RECOMMENDED_VALID) {
optlen = tp->t_maxopd - tp->t_maxseg;
if (ifsr->mss_recommended ==
IF_CELL_UL_MSS_RECOMMENDED_NONE &&
tp->t_cached_maxopd > 0 &&
tp->t_maxopd < tp->t_cached_maxopd) {
tp->t_maxopd = tp->t_cached_maxopd;
tcpstat.tcps_mss_to_default++;
} else if (ifsr->mss_recommended ==
IF_CELL_UL_MSS_RECOMMENDED_MEDIUM &&
tp->t_maxopd > tcp_mss_rec_medium) {
tp->t_cached_maxopd = tp->t_maxopd;
tp->t_maxopd = tcp_mss_rec_medium;
tcpstat.tcps_mss_to_medium++;
} else if (ifsr->mss_recommended ==
IF_CELL_UL_MSS_RECOMMENDED_LOW &&
tp->t_maxopd > tcp_mss_rec_low) {
tp->t_cached_maxopd = tp->t_maxopd;
tp->t_maxopd = tcp_mss_rec_low;
tcpstat.tcps_mss_to_low++;
}
tp->t_maxseg = tp->t_maxopd - optlen;
/*
* clear the cached value if it is same as the current
*/
if (tp->t_maxopd == tp->t_cached_maxopd) {
tp->t_cached_maxopd = 0;
}
}
}
void
tcp_update_mss_locked(struct socket *so, struct ifnet *ifp)
{
struct inpcb *inp = sotoinpcb(so);
struct tcpcb *tp = intotcpcb(inp);
if (ifp == NULL && (ifp = inp->inp_last_outifp) == NULL) {
return;
}
if (!IFNET_IS_CELLULAR(ifp)) {
/*
* This optimization is implemented for cellular
* networks only
*/
return;
}
if (tp->t_state <= TCPS_CLOSE_WAIT) {
/*
* If the connection is currently doing or has done PMTU
* blackhole detection, do not change the MSS
*/
if (tp->t_flags & TF_BLACKHOLE) {
return;
}
if (ifp->if_link_status == NULL) {
return;
}
tcp_update_mss_core(tp, ifp);
}
}
void
tcp_itimer(struct inpcbinfo *ipi)
{
struct inpcb *inp, *nxt;
if (lck_rw_try_lock_exclusive(&ipi->ipi_lock) == FALSE) {
if (tcp_itimer_done == TRUE) {
tcp_itimer_done = FALSE;
os_atomic_inc(&ipi->ipi_timer_req.intimer_fast, relaxed);
return;
}
/* Upgrade failed, lost lock now take it again exclusive */
lck_rw_lock_exclusive(&ipi->ipi_lock);
}
tcp_itimer_done = TRUE;
LIST_FOREACH_SAFE(inp, &tcb, inp_list, nxt) {
struct socket *so;
struct ifnet *ifp;
if (inp->inp_ppcb == NULL ||
in_pcb_checkstate(inp, WNT_ACQUIRE, 0) == WNT_STOPUSING) {
continue;
}
so = inp->inp_socket;
ifp = inp->inp_last_outifp;
socket_lock(so, 1);
if (in_pcb_checkstate(inp, WNT_RELEASE, 1) == WNT_STOPUSING) {
socket_unlock(so, 1);
continue;
}
so_check_extended_bk_idle_time(so);
if (ipi->ipi_flags & INPCBINFO_UPDATE_MSS) {
tcp_update_mss_locked(so, NULL);
}
socket_unlock(so, 1);
/*
* Defunct all system-initiated background sockets if the
* socket is using the cellular interface and the interface
* has its LQM set to abort.
*/
if ((ipi->ipi_flags & INPCBINFO_HANDLE_LQM_ABORT) &&
IS_SO_TC_BACKGROUNDSYSTEM(so->so_traffic_class) &&
ifp != NULL && IFNET_IS_CELLULAR(ifp) &&
(ifp->if_interface_state.valid_bitmask &
IF_INTERFACE_STATE_LQM_STATE_VALID) &&
ifp->if_interface_state.lqm_state ==
IFNET_LQM_THRESH_ABORT) {
socket_defunct(current_proc(), so,
SHUTDOWN_SOCKET_LEVEL_DISCONNECT_ALL);
}
}
ipi->ipi_flags &= ~(INPCBINFO_UPDATE_MSS | INPCBINFO_HANDLE_LQM_ABORT);
lck_rw_done(&ipi->ipi_lock);
}