[apple/xnu.git] / bsd / netinet / tcp_cc.c

/*
 * Copyright (c) 2013-2014 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@
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/syslog.h>
#include <sys/protosw.h>
#include <sys/socketvar.h>
#include <sys/kern_control.h>
#include <sys/domain.h>

#include <netinet/in.h>
#include <netinet/tcp.h>
#include <netinet/tcp_var.h>
#include <netinet/tcp_cc.h>
#include <mach/sdt.h>
#include <libkern/OSAtomic.h>

struct tcp_cc_debug_state {
	u_int64_t ccd_tsns;
	char ccd_srcaddr[INET6_ADDRSTRLEN];
	uint16_t ccd_srcport;
	char ccd_destaddr[INET6_ADDRSTRLEN];
	uint16_t ccd_destport;
	uint32_t ccd_snd_cwnd;
	uint32_t ccd_snd_wnd;
	uint32_t ccd_snd_ssthresh;
	uint32_t ccd_rttcur;
	uint32_t ccd_rxtcur;
	uint32_t ccd_srtt;
	uint32_t ccd_event;
	uint32_t ccd_sndcc;
	uint32_t ccd_sndhiwat;
	uint32_t ccd_bytes_acked;
	union {
		struct {
			uint32_t ccd_last_max;
			uint32_t ccd_tcp_win;
			uint32_t ccd_target_win;
			uint32_t ccd_avg_lastmax;
			uint32_t ccd_mean_deviation;
		} cubic_state;
	} u;
};

int tcp_cc_debug = 0;
SYSCTL_INT(_net_inet_tcp, OID_AUTO, cc_debug, CTLFLAG_RW | CTLFLAG_LOCKED,
	&tcp_cc_debug, 0, "Enable debug data collection");

extern struct tcp_cc_algo tcp_cc_newreno;
SYSCTL_INT(_net_inet_tcp, OID_AUTO, newreno_sockets,
	CTLFLAG_RD | CTLFLAG_LOCKED, &tcp_cc_newreno.num_sockets,
	0, "Number of sockets using newreno");

extern struct tcp_cc_algo tcp_cc_ledbat;
SYSCTL_INT(_net_inet_tcp, OID_AUTO, background_sockets,
	CTLFLAG_RD | CTLFLAG_LOCKED, &tcp_cc_ledbat.num_sockets,
	0, "Number of sockets using background transport");

extern struct tcp_cc_algo tcp_cc_cubic;
SYSCTL_INT(_net_inet_tcp, OID_AUTO, cubic_sockets,
	CTLFLAG_RD | CTLFLAG_LOCKED,&tcp_cc_cubic.num_sockets, 
	0, "Number of sockets using cubic");

int tcp_use_newreno = 0;
SYSCTL_INT(_net_inet_tcp, OID_AUTO, use_newreno,
	CTLFLAG_RW | CTLFLAG_LOCKED, &tcp_use_newreno, 0, 
	"Use TCP NewReno by default");

 #define SET_SNDSB_IDEAL_SIZE(sndsb, size) \
	sndsb->sb_idealsize = min(max(tcp_sendspace, tp->snd_ssthresh), \
	tcp_autosndbuf_max);

/* Array containing pointers to currently implemented TCP CC algorithms */
struct tcp_cc_algo* tcp_cc_algo_list[TCP_CC_ALGO_COUNT];
struct zone *tcp_cc_zone;

/* Information for colelcting TCP debug information using control socket */
#define TCP_CCDEBUG_CONTROL_NAME "com.apple.network.tcp_ccdebug"
#define TCP_CCDBG_NOUNIT 0xffffffff
static kern_ctl_ref tcp_ccdbg_ctlref = NULL;
volatile UInt32 tcp_ccdbg_unit = TCP_CCDBG_NOUNIT;

void tcp_cc_init(void);
static void tcp_cc_control_register(void);
static errno_t tcp_ccdbg_control_connect(kern_ctl_ref kctl,
	struct sockaddr_ctl *sac, void **uinfo);
static errno_t tcp_ccdbg_control_disconnect(kern_ctl_ref kctl,
	u_int32_t unit, void *uinfo);
static struct tcp_cc_algo tcp_cc_algo_none;
/*
 * Initialize TCP congestion control algorithms.
 */
 
void
tcp_cc_init(void)
{
	bzero(&tcp_cc_algo_list, sizeof(tcp_cc_algo_list));
	bzero(&tcp_cc_algo_none, sizeof(tcp_cc_algo_none));

	tcp_cc_algo_list[TCP_CC_ALGO_NONE] = &tcp_cc_algo_none;
	tcp_cc_algo_list[TCP_CC_ALGO_NEWRENO_INDEX] = &tcp_cc_newreno;
	tcp_cc_algo_list[TCP_CC_ALGO_BACKGROUND_INDEX] = &tcp_cc_ledbat;
	tcp_cc_algo_list[TCP_CC_ALGO_CUBIC_INDEX] = &tcp_cc_cubic;

	tcp_cc_control_register();
}

static void
tcp_cc_control_register(void)
{
	struct kern_ctl_reg ccdbg_control;
	errno_t err;

	bzero(&ccdbg_control, sizeof(ccdbg_control));
	strlcpy(ccdbg_control.ctl_name, TCP_CCDEBUG_CONTROL_NAME,
	    sizeof(ccdbg_control.ctl_name));
	ccdbg_control.ctl_connect = tcp_ccdbg_control_connect;
	ccdbg_control.ctl_disconnect = tcp_ccdbg_control_disconnect;
	ccdbg_control.ctl_flags |= CTL_FLAG_PRIVILEGED;
	ccdbg_control.ctl_flags |= CTL_FLAG_REG_SOCK_STREAM;

	err = ctl_register(&ccdbg_control, &tcp_ccdbg_ctlref);
	if (err != 0) {
		log(LOG_ERR, "failed to register tcp_cc debug control");
	}
}

/* Allow only one socket to connect at any time for debugging */
static errno_t
tcp_ccdbg_control_connect(kern_ctl_ref kctl, struct sockaddr_ctl *sac,
	void **uinfo)
{
#pragma unused(kctl)
#pragma unused(uinfo)

	UInt32 old_value = TCP_CCDBG_NOUNIT;
	UInt32 new_value = sac->sc_unit;

	if (tcp_ccdbg_unit != old_value)
		return (EALREADY);

	if (OSCompareAndSwap(old_value, new_value, &tcp_ccdbg_unit))
		return (0);
	else
		return (EALREADY);
}

static errno_t
tcp_ccdbg_control_disconnect(kern_ctl_ref kctl, u_int32_t unit, void *uinfo)
{
#pragma unused(kctl, unit, uinfo)

	if (unit == tcp_ccdbg_unit) {
		UInt32 old_value = tcp_ccdbg_unit;
		UInt32 new_value = TCP_CCDBG_NOUNIT;
		if (tcp_ccdbg_unit == new_value)
			return (0);

		if (!OSCompareAndSwap(old_value, new_value,
			&tcp_ccdbg_unit))
			log(LOG_DEBUG, 
			    "failed to disconnect tcp_cc debug control");
	}
	return (0);
}

inline void
tcp_ccdbg_trace(struct tcpcb *tp, struct tcphdr *th, int32_t event)
{
#if !CONFIG_DTRACE
#pragma unused(th)
#endif /* !CONFIG_DTRACE */
	struct inpcb *inp = tp->t_inpcb;

	if (tcp_cc_debug && tcp_ccdbg_unit > 0) {
		struct tcp_cc_debug_state dbg_state;
		struct timespec tv;

		bzero(&dbg_state, sizeof(dbg_state));
		
		nanotime(&tv);
		/* Take time in seconds */
		dbg_state.ccd_tsns = (tv.tv_sec * 1000000000) + tv.tv_nsec;
		inet_ntop(SOCK_DOM(inp->inp_socket), 
		    ((SOCK_DOM(inp->inp_socket) == PF_INET) ?
		    (void *)&inp->inp_laddr.s_addr :
		    (void *)&inp->in6p_laddr), dbg_state.ccd_srcaddr,
		    sizeof(dbg_state.ccd_srcaddr));
		dbg_state.ccd_srcport = ntohs(inp->inp_lport);
		inet_ntop(SOCK_DOM(inp->inp_socket),
		    ((SOCK_DOM(inp->inp_socket) == PF_INET) ?
		    (void *)&inp->inp_faddr.s_addr :
		    (void *)&inp->in6p_faddr), dbg_state.ccd_destaddr,
		    sizeof(dbg_state.ccd_destaddr));
		dbg_state.ccd_destport = ntohs(inp->inp_fport);

		dbg_state.ccd_snd_cwnd = tp->snd_cwnd;
		dbg_state.ccd_snd_wnd = tp->snd_wnd;
		dbg_state.ccd_snd_ssthresh = tp->snd_ssthresh;
		dbg_state.ccd_rttcur = tp->t_rttcur;
		dbg_state.ccd_rxtcur = tp->t_rxtcur;
		dbg_state.ccd_srtt = tp->t_srtt >> TCP_RTT_SHIFT;
		dbg_state.ccd_event = event;
		dbg_state.ccd_sndcc = inp->inp_socket->so_snd.sb_cc;
		dbg_state.ccd_sndhiwat = inp->inp_socket->so_snd.sb_hiwat;
		dbg_state.ccd_bytes_acked = tp->t_bytes_acked;
		switch (tp->tcp_cc_index) {
		    case TCP_CC_ALGO_CUBIC_INDEX:
			dbg_state.u.cubic_state.ccd_last_max =
			    tp->t_ccstate->cub_last_max;
			dbg_state.u.cubic_state.ccd_tcp_win =
			    tp->t_ccstate->cub_tcp_win;
			dbg_state.u.cubic_state.ccd_target_win =
			    tp->t_ccstate->cub_target_win;
			dbg_state.u.cubic_state.ccd_avg_lastmax =
			    tp->t_ccstate->cub_avg_lastmax;
			dbg_state.u.cubic_state.ccd_mean_deviation =
			    tp->t_ccstate->cub_mean_dev;
			break;
		    default:
			break;
		}

		ctl_enqueuedata(tcp_ccdbg_ctlref, tcp_ccdbg_unit,
			&dbg_state, sizeof(dbg_state), 0);
	}
	DTRACE_TCP5(cc, void, NULL, struct inpcb *, inp,
		struct tcpcb *, tp, struct tcphdr *, th, int32_t, event);
}

void tcp_cc_resize_sndbuf(struct tcpcb *tp)
{
	struct sockbuf *sb;
	/*
	 * If the send socket buffer size is bigger than ssthresh,
	 * it is time to trim it because we do not want to hold
	 * too many mbufs in the socket buffer
	 */
	sb = &tp->t_inpcb->inp_socket->so_snd;
	if (sb->sb_hiwat > tp->snd_ssthresh &&
		(sb->sb_flags & SB_AUTOSIZE)) {
		if (sb->sb_idealsize > tp->snd_ssthresh) {
			SET_SNDSB_IDEAL_SIZE(sb, tp->snd_ssthresh);
		}
		sb->sb_flags |= SB_TRIM;
	}
}

void tcp_bad_rexmt_fix_sndbuf(struct tcpcb *tp)
{
	struct sockbuf *sb;
	sb = &tp->t_inpcb->inp_socket->so_snd;
	if ((sb->sb_flags & (SB_TRIM|SB_AUTOSIZE)) == (SB_TRIM|SB_AUTOSIZE)) {
		/*
		 * If there was a retransmission that was not necessary 
		 * then the size of socket buffer can be restored to
		 * what it was before
		 */
		SET_SNDSB_IDEAL_SIZE(sb, tp->snd_ssthresh);
		if (sb->sb_hiwat <= sb->sb_idealsize) {
			sbreserve(sb, sb->sb_idealsize);
			sb->sb_flags &= ~SB_TRIM;
		}
	}
}

/*
 * Calculate initial cwnd according to RFC3390.
 *
 * Keep the old ss_fltsz sysctl for ABI compabitility issues.
 * but it will be overriden if tcp_do_rfc3390 sysctl when it is set.
 */
void
tcp_cc_cwnd_init_or_reset(struct tcpcb *tp)
{
	if (tp->t_flags & TF_LOCAL) {
		tp->snd_cwnd = tp->t_maxseg * ss_fltsz_local;
	} else {
		/* initial congestion window according to RFC 3390 */
		if (tcp_do_rfc3390)
			tp->snd_cwnd = min(4 * tp->t_maxseg,
				max(2 * tp->t_maxseg, TCP_CC_CWND_INIT_BYTES));
		else
			tp->snd_cwnd = tp->t_maxseg * ss_fltsz;
	}
}

/*
 * Indicate whether this ack should be delayed.
 * Here is the explanation for different settings of tcp_delack_enabled:
 *  - when set to 1, the bhavior is same as when set to 2. We kept this 
 *    for binary compatibility.
 *  - when set to 2, will "ack every other packet"
 *      - if our last ack wasn't a 0-sized window.
 *      - if the peer hasn't sent us a TH_PUSH data packet (radar 3649245). 
 *              If TH_PUSH is set, take this as a clue that we need to ACK 
 *              with no delay. This helps higher level protocols who 
 *              won't send us more data even if the window is open 
 *              because their last "segment" hasn't been ACKed
 *  - when set to 3,  will do "streaming detection" 
 *      - if we receive more than "maxseg_unacked" full packets 
 *        in the last 100ms
 *      - if the connection is not in slow-start or idle or 
 *        loss/recovery states
 *      - if those criteria aren't met, it will ack every other packet.
 */
int
tcp_cc_delay_ack(struct tcpcb *tp, struct tcphdr *th)
{
	/* If any flags other than TH_ACK is set, set "end-of-write" bit */
	if ((th->th_flags & ~TH_ACK))
		tp->t_flagsext |= TF_STREAMEOW;
	else    
		tp->t_flagsext &= ~(TF_STREAMEOW);
    
	switch (tcp_delack_enabled) {
	    case 1:
	    case 2:
		if ((tp->t_flags & TF_RXWIN0SENT) == 0 &&
		    (th->th_flags & TH_PUSH) == 0 &&
		    (tp->t_unacksegs == 1))
			return(1);
		break;  
	    case 3:
		if ((tp->t_flags & TF_RXWIN0SENT) == 0 &&
		    (th->th_flags & TH_PUSH) == 0 &&
		    ((tp->t_unacksegs == 1) ||
		    ((tp->t_flags & TF_STRETCHACK) != 0 &&
			tp->t_unacksegs < (maxseg_unacked))))
			return(1);
		break;
	}
	return(0);
}

void
tcp_cc_allocate_state(struct tcpcb *tp)
{
	if (tp->tcp_cc_index == TCP_CC_ALGO_CUBIC_INDEX &&
		tp->t_ccstate == NULL) {
		tp->t_ccstate = (struct tcp_ccstate *)zalloc(tcp_cc_zone);

		/*
		 * If we could not allocate memory for congestion control
		 * state, revert to using TCP NewReno as it does not
		 * require any state
		 */
		if (tp->t_ccstate == NULL)
			tp->tcp_cc_index = TCP_CC_ALGO_NEWRENO_INDEX;
		else
			bzero(tp->t_ccstate, sizeof(*tp->t_ccstate));
	}
}

/*
 * If stretch ack was disabled automatically on long standing connections, 
 * re-evaluate the situation after 15 minutes to enable it.
 */
#define	TCP_STRETCHACK_DISABLE_WIN	(15 * 60 * TCP_RETRANSHZ)
void
tcp_cc_after_idle_stretchack(struct tcpcb *tp)
{
	int32_t tdiff;

	if (!(tp->t_flagsext & TF_DISABLE_STRETCHACK))
		return;

	tdiff = timer_diff(tcp_now, 0, tp->rcv_nostrack_ts, 0);
	if (tdiff < 0)
		tdiff = -tdiff;

	if (tdiff > TCP_STRETCHACK_DISABLE_WIN) {
		tp->t_flagsext &= ~TF_DISABLE_STRETCHACK;
		tp->t_stretchack_delayed = 0;

		tcp_reset_stretch_ack(tp);
	}
}
Commit	Line	Data
fe8ab488 A	1	/*
	2	* Copyright (c) 2013-2014 Apple Inc. All rights reserved.
	3	*
	4	* @APPLE_OSREFERENCE_LICENSE_HEADER_START@
	5	*
	6	* This file contains Original Code and/or Modifications of Original Code
	7	* as defined in and that are subject to the Apple Public Source License
	8	* Version 2.0 (the 'License'). You may not use this file except in
	9	* compliance with the License. The rights granted to you under the License
	10	* may not be used to create, or enable the creation or redistribution of,
	11	* unlawful or unlicensed copies of an Apple operating system, or to
	12	* circumvent, violate, or enable the circumvention or violation of, any
	13	* terms of an Apple operating system software license agreement.
	14	*
	15	* Please obtain a copy of the License at
	16	* http://www.opensource.apple.com/apsl/ and read it before using this file.
	17	*
	18	* The Original Code and all software distributed under the License are
	19	* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
	20	* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
	21	* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
	22	* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
	23	* Please see the License for the specific language governing rights and
	24	* limitations under the License.
	25	*
	26	* @APPLE_OSREFERENCE_LICENSE_HEADER_END@
	27	*/
	28
	29	#include <sys/param.h>
	30	#include <sys/systm.h>
	31	#include <sys/kernel.h>
	32	#include <sys/syslog.h>
	33	#include <sys/protosw.h>
	34	#include <sys/socketvar.h>
	35	#include <sys/kern_control.h>
	36	#include <sys/domain.h>
	37
	38	#include <netinet/in.h>
	39	#include <netinet/tcp.h>
	40	#include <netinet/tcp_var.h>
	41	#include <netinet/tcp_cc.h>
	42	#include <mach/sdt.h>
	43	#include <libkern/OSAtomic.h>
	44
	45	struct tcp_cc_debug_state {
	46	u_int64_t ccd_tsns;
	47	char ccd_srcaddr[INET6_ADDRSTRLEN];
	48	uint16_t ccd_srcport;
	49	char ccd_destaddr[INET6_ADDRSTRLEN];
	50	uint16_t ccd_destport;
	51	uint32_t ccd_snd_cwnd;
	52	uint32_t ccd_snd_wnd;
	53	uint32_t ccd_snd_ssthresh;
	54	uint32_t ccd_rttcur;
	55	uint32_t ccd_rxtcur;
	56	uint32_t ccd_srtt;
	57	uint32_t ccd_event;
	58	uint32_t ccd_sndcc;
	59	uint32_t ccd_sndhiwat;
	60	uint32_t ccd_bytes_acked;
	61	union {
	62	struct {
	63	uint32_t ccd_last_max;
	64	uint32_t ccd_tcp_win;
65	uint32_t ccd_target_win;
66	uint32_t ccd_avg_lastmax;
67	uint32_t ccd_mean_deviation;
68	} cubic_state;
69	} u;
70	};
71
72	int tcp_cc_debug = 0;
73	SYSCTL_INT(_net_inet_tcp, OID_AUTO, cc_debug, CTLFLAG_RW \| CTLFLAG_LOCKED,
74	&tcp_cc_debug, 0, "Enable debug data collection");
75
76	extern struct tcp_cc_algo tcp_cc_newreno;
77	SYSCTL_INT(_net_inet_tcp, OID_AUTO, newreno_sockets,
78	CTLFLAG_RD \| CTLFLAG_LOCKED, &tcp_cc_newreno.num_sockets,
79	0, "Number of sockets using newreno");
80
81	extern struct tcp_cc_algo tcp_cc_ledbat;
82	SYSCTL_INT(_net_inet_tcp, OID_AUTO, background_sockets,
83	CTLFLAG_RD \| CTLFLAG_LOCKED, &tcp_cc_ledbat.num_sockets,
84	0, "Number of sockets using background transport");
85
86	extern struct tcp_cc_algo tcp_cc_cubic;
87	SYSCTL_INT(_net_inet_tcp, OID_AUTO, cubic_sockets,
88	CTLFLAG_RD \| CTLFLAG_LOCKED,&tcp_cc_cubic.num_sockets,
89	0, "Number of sockets using cubic");
90
91	int tcp_use_newreno = 0;
92	SYSCTL_INT(_net_inet_tcp, OID_AUTO, use_newreno,
93	CTLFLAG_RW \| CTLFLAG_LOCKED, &tcp_use_newreno, 0,
94	"Use TCP NewReno by default");
95
96	#define SET_SNDSB_IDEAL_SIZE(sndsb, size) \
97	sndsb->sb_idealsize = min(max(tcp_sendspace, tp->snd_ssthresh), \
98	tcp_autosndbuf_max);
99
100	/* Array containing pointers to currently implemented TCP CC algorithms */
101	struct tcp_cc_algo* tcp_cc_algo_list[TCP_CC_ALGO_COUNT];
102	struct zone *tcp_cc_zone;
103
104	/* Information for colelcting TCP debug information using control socket */
105	#define TCP_CCDEBUG_CONTROL_NAME "com.apple.network.tcp_ccdebug"
106	#define TCP_CCDBG_NOUNIT 0xffffffff
107	static kern_ctl_ref tcp_ccdbg_ctlref = NULL;
108	volatile UInt32 tcp_ccdbg_unit = TCP_CCDBG_NOUNIT;
109
110	void tcp_cc_init(void);
111	static void tcp_cc_control_register(void);
112	static errno_t tcp_ccdbg_control_connect(kern_ctl_ref kctl,
113	struct sockaddr_ctl sac, void *uinfo);
114	static errno_t tcp_ccdbg_control_disconnect(kern_ctl_ref kctl,
115	u_int32_t unit, void *uinfo);
116	static struct tcp_cc_algo tcp_cc_algo_none;
117	/*
118	* Initialize TCP congestion control algorithms.
119	*/
120
121	void
122	tcp_cc_init(void)
123	{
124	bzero(&tcp_cc_algo_list, sizeof(tcp_cc_algo_list));
125	bzero(&tcp_cc_algo_none, sizeof(tcp_cc_algo_none));
126
127	tcp_cc_algo_list[TCP_CC_ALGO_NONE] = &tcp_cc_algo_none;
128	tcp_cc_algo_list[TCP_CC_ALGO_NEWRENO_INDEX] = &tcp_cc_newreno;
129	tcp_cc_algo_list[TCP_CC_ALGO_BACKGROUND_INDEX] = &tcp_cc_ledbat;
130	tcp_cc_algo_list[TCP_CC_ALGO_CUBIC_INDEX] = &tcp_cc_cubic;
131
132	tcp_cc_control_register();
133	}
134
135	static void
136	tcp_cc_control_register(void)
137	{
138	struct kern_ctl_reg ccdbg_control;
139	errno_t err;
140
141	bzero(&ccdbg_control, sizeof(ccdbg_control));
142	strlcpy(ccdbg_control.ctl_name, TCP_CCDEBUG_CONTROL_NAME,
143	sizeof(ccdbg_control.ctl_name));
144	ccdbg_control.ctl_connect = tcp_ccdbg_control_connect;
145	ccdbg_control.ctl_disconnect = tcp_ccdbg_control_disconnect;
146	ccdbg_control.ctl_flags \|= CTL_FLAG_PRIVILEGED;
147	ccdbg_control.ctl_flags \|= CTL_FLAG_REG_SOCK_STREAM;
148
149	err = ctl_register(&ccdbg_control, &tcp_ccdbg_ctlref);
150	if (err != 0) {
151	log(LOG_ERR, "failed to register tcp_cc debug control");
152	}
153	}
154
155	/* Allow only one socket to connect at any time for debugging */
156	static errno_t
157	tcp_ccdbg_control_connect(kern_ctl_ref kctl, struct sockaddr_ctl *sac,
158	void **uinfo)
159	{
160	#pragma unused(kctl)
161	#pragma unused(uinfo)
162
163	UInt32 old_value = TCP_CCDBG_NOUNIT;
164	UInt32 new_value = sac->sc_unit;
165
166	if (tcp_ccdbg_unit != old_value)
167	return (EALREADY);
168
169	if (OSCompareAndSwap(old_value, new_value, &tcp_ccdbg_unit))
170	return (0);
171	else
172	return (EALREADY);
173	}
174
175	static errno_t
176	tcp_ccdbg_control_disconnect(kern_ctl_ref kctl, u_int32_t unit, void *uinfo)
177	{
178	#pragma unused(kctl, unit, uinfo)
179
180	if (unit == tcp_ccdbg_unit) {
181	UInt32 old_value = tcp_ccdbg_unit;
182	UInt32 new_value = TCP_CCDBG_NOUNIT;
183	if (tcp_ccdbg_unit == new_value)
184	return (0);
185
186	if (!OSCompareAndSwap(old_value, new_value,
187	&tcp_ccdbg_unit))
188	log(LOG_DEBUG,
189	"failed to disconnect tcp_cc debug control");
190	}
191	return (0);
192	}
193
194	inline void
195	tcp_ccdbg_trace(struct tcpcb tp, struct tcphdr th, int32_t event)
196	{
197	#if !CONFIG_DTRACE
198	#pragma unused(th)
199	#endif /* !CONFIG_DTRACE */
200	struct inpcb *inp = tp->t_inpcb;
201
202	if (tcp_cc_debug && tcp_ccdbg_unit > 0) {
203	struct tcp_cc_debug_state dbg_state;
204	struct timespec tv;
205
206	bzero(&dbg_state, sizeof(dbg_state));
207
208	nanotime(&tv);
209	/* Take time in seconds */
210	dbg_state.ccd_tsns = (tv.tv_sec * 1000000000) + tv.tv_nsec;
211	inet_ntop(SOCK_DOM(inp->inp_socket),
212	((SOCK_DOM(inp->inp_socket) == PF_INET) ?
213	(void *)&inp->inp_laddr.s_addr :
214	(void *)&inp->in6p_laddr), dbg_state.ccd_srcaddr,
215	sizeof(dbg_state.ccd_srcaddr));
216	dbg_state.ccd_srcport = ntohs(inp->inp_lport);
217	inet_ntop(SOCK_DOM(inp->inp_socket),
218	((SOCK_DOM(inp->inp_socket) == PF_INET) ?
219	(void *)&inp->inp_faddr.s_addr :
220	(void *)&inp->in6p_faddr), dbg_state.ccd_destaddr,
221	sizeof(dbg_state.ccd_destaddr));
222	dbg_state.ccd_destport = ntohs(inp->inp_fport);
223
224	dbg_state.ccd_snd_cwnd = tp->snd_cwnd;
225	dbg_state.ccd_snd_wnd = tp->snd_wnd;
226	dbg_state.ccd_snd_ssthresh = tp->snd_ssthresh;
227	dbg_state.ccd_rttcur = tp->t_rttcur;
228	dbg_state.ccd_rxtcur = tp->t_rxtcur;
229	dbg_state.ccd_srtt = tp->t_srtt >> TCP_RTT_SHIFT;
230	dbg_state.ccd_event = event;
231	dbg_state.ccd_sndcc = inp->inp_socket->so_snd.sb_cc;
232	dbg_state.ccd_sndhiwat = inp->inp_socket->so_snd.sb_hiwat;
233	dbg_state.ccd_bytes_acked = tp->t_bytes_acked;
234	switch (tp->tcp_cc_index) {
235	case TCP_CC_ALGO_CUBIC_INDEX:
236	dbg_state.u.cubic_state.ccd_last_max =
237	tp->t_ccstate->cub_last_max;
238	dbg_state.u.cubic_state.ccd_tcp_win =
239	tp->t_ccstate->cub_tcp_win;
240	dbg_state.u.cubic_state.ccd_target_win =
241	tp->t_ccstate->cub_target_win;
242	dbg_state.u.cubic_state.ccd_avg_lastmax =
243	tp->t_ccstate->cub_avg_lastmax;
244	dbg_state.u.cubic_state.ccd_mean_deviation =
245	tp->t_ccstate->cub_mean_dev;
246	break;
247	default:
248	break;
249	}
250
251	ctl_enqueuedata(tcp_ccdbg_ctlref, tcp_ccdbg_unit,
252	&dbg_state, sizeof(dbg_state), 0);
253	}
254	DTRACE_TCP5(cc, void, NULL, struct inpcb *, inp,
255	struct tcpcb , tp, struct tcphdr , th, int32_t, event);
256	}
257
258	void tcp_cc_resize_sndbuf(struct tcpcb *tp)
259	{
260	struct sockbuf *sb;
261	/*
262	* If the send socket buffer size is bigger than ssthresh,
263	* it is time to trim it because we do not want to hold
264	* too many mbufs in the socket buffer
265	*/
266	sb = &tp->t_inpcb->inp_socket->so_snd;
267	if (sb->sb_hiwat > tp->snd_ssthresh &&
268	(sb->sb_flags & SB_AUTOSIZE)) {
269	if (sb->sb_idealsize > tp->snd_ssthresh) {
270	SET_SNDSB_IDEAL_SIZE(sb, tp->snd_ssthresh);
271	}
272	sb->sb_flags \|= SB_TRIM;
273	}
274	}
275
276	void tcp_bad_rexmt_fix_sndbuf(struct tcpcb *tp)
277	{
278	struct sockbuf *sb;
279	sb = &tp->t_inpcb->inp_socket->so_snd;
280	if ((sb->sb_flags & (SB_TRIM\|SB_AUTOSIZE)) == (SB_TRIM\|SB_AUTOSIZE)) {
281	/*
282	* If there was a retransmission that was not necessary
283	* then the size of socket buffer can be restored to
284	* what it was before
285	*/
286	SET_SNDSB_IDEAL_SIZE(sb, tp->snd_ssthresh);
287	if (sb->sb_hiwat <= sb->sb_idealsize) {
288	sbreserve(sb, sb->sb_idealsize);
289	sb->sb_flags &= ~SB_TRIM;
290	}
291	}
292	}
293
294	/*
295	* Calculate initial cwnd according to RFC3390.
296	*
297	* Keep the old ss_fltsz sysctl for ABI compabitility issues.
298	* but it will be overriden if tcp_do_rfc3390 sysctl when it is set.
299	*/
300	void
301	tcp_cc_cwnd_init_or_reset(struct tcpcb *tp)
302	{
303	if (tp->t_flags & TF_LOCAL) {
304	tp->snd_cwnd = tp->t_maxseg * ss_fltsz_local;
305	} else {
306	/* initial congestion window according to RFC 3390 */
307	if (tcp_do_rfc3390)
308	tp->snd_cwnd = min(4 * tp->t_maxseg,
309	max(2 * tp->t_maxseg, TCP_CC_CWND_INIT_BYTES));
310	else
311	tp->snd_cwnd = tp->t_maxseg * ss_fltsz;
312	}
313	}
314
315	/*
316	* Indicate whether this ack should be delayed.
317	* Here is the explanation for different settings of tcp_delack_enabled:
318	* - when set to 1, the bhavior is same as when set to 2. We kept this
319	* for binary compatibility.
320	* - when set to 2, will "ack every other packet"
321	* - if our last ack wasn't a 0-sized window.
322	* - if the peer hasn't sent us a TH_PUSH data packet (radar 3649245).
323	* If TH_PUSH is set, take this as a clue that we need to ACK
324	* with no delay. This helps higher level protocols who
325	* won't send us more data even if the window is open
326	* because their last "segment" hasn't been ACKed
327	* - when set to 3, will do "streaming detection"
328	* - if we receive more than "maxseg_unacked" full packets
329	* in the last 100ms
330	* - if the connection is not in slow-start or idle or
331	* loss/recovery states
332	* - if those criteria aren't met, it will ack every other packet.
333	*/
334	int
335	tcp_cc_delay_ack(struct tcpcb tp, struct tcphdr th)
336	{
337	/* If any flags other than TH_ACK is set, set "end-of-write" bit */
338	if ((th->th_flags & ~TH_ACK))
339	tp->t_flagsext \|= TF_STREAMEOW;
340	else
341	tp->t_flagsext &= ~(TF_STREAMEOW);
342
343	switch (tcp_delack_enabled) {
344	case 1:
345	case 2:
346	if ((tp->t_flags & TF_RXWIN0SENT) == 0 &&
347	(th->th_flags & TH_PUSH) == 0 &&
348	(tp->t_unacksegs == 1))
349	return(1);
350	break;
351	case 3:
352	if ((tp->t_flags & TF_RXWIN0SENT) == 0 &&
353	(th->th_flags & TH_PUSH) == 0 &&
354	((tp->t_unacksegs == 1) \|\|
355	((tp->t_flags & TF_STRETCHACK) != 0 &&
356	tp->t_unacksegs < (maxseg_unacked))))
357	return(1);
358	break;
359	}
360	return(0);
361	}
362
363	void
364	tcp_cc_allocate_state(struct tcpcb *tp)
365	{
366	if (tp->tcp_cc_index == TCP_CC_ALGO_CUBIC_INDEX &&
367	tp->t_ccstate == NULL) {
368	tp->t_ccstate = (struct tcp_ccstate *)zalloc(tcp_cc_zone);
369
370	/*
371	* If we could not allocate memory for congestion control
372	* state, revert to using TCP NewReno as it does not
373	* require any state
374	*/
375	if (tp->t_ccstate == NULL)
376	tp->tcp_cc_index = TCP_CC_ALGO_NEWRENO_INDEX;
377	else
378	bzero(tp->t_ccstate, sizeof(*tp->t_ccstate));
379	}
380	}
381
382	/*
383	* If stretch ack was disabled automatically on long standing connections,
384	* re-evaluate the situation after 15 minutes to enable it.
385	*/
386	#define TCP_STRETCHACK_DISABLE_WIN (15 * 60 * TCP_RETRANSHZ)
387	void
388	tcp_cc_after_idle_stretchack(struct tcpcb *tp)
389	{
390	int32_t tdiff;
391
392	if (!(tp->t_flagsext & TF_DISABLE_STRETCHACK))
393	return;
394
395	tdiff = timer_diff(tcp_now, 0, tp->rcv_nostrack_ts, 0);
396	if (tdiff < 0)
397	tdiff = -tdiff;
398
399	if (tdiff > TCP_STRETCHACK_DISABLE_WIN) {
400	tp->t_flagsext &= ~TF_DISABLE_STRETCHACK;
401	tp->t_stretchack_delayed = 0;
402
403	tcp_reset_stretch_ack(tp);
404	}
405	}