/*
 * Copyright (c) 2003, 2004 Jeffrey M. Hsu.  All rights reserved.
 * Copyright (c) 2003, 2004 The DragonFly Project.  All rights reserved.
 *
 * This code is derived from software contributed to The DragonFly Project
 * by Jeffrey M. Hsu.
 *
 * 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. Neither the name of The DragonFly Project 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 COPYRIGHT HOLDERS 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
 * COPYRIGHT HOLDERS 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.
 */

/*
 * 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. 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_subr.c	8.2 (Berkeley) 5/24/95
 * $FreeBSD: src/sys/netinet/tcp_subr.c,v 1.73.2.31 2003/01/24 05:11:34 sam Exp $
 */

#include "opt_inet.h"
#include "opt_inet6.h"
#include "opt_tcpdebug.h"

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/callout.h>
#include <sys/kernel.h>
#include <sys/sysctl.h>
#include <sys/malloc.h>
#include <sys/mpipe.h>
#include <sys/mbuf.h>
#ifdef INET6
#include <sys/domain.h>
#endif
#include <sys/proc.h>
#include <sys/caps.h>
#include <sys/socket.h>
#include <sys/socketops.h>
#include <sys/socketvar.h>
#include <sys/protosw.h>
#include <sys/random.h>
#include <sys/in_cksum.h>
#include <sys/ktr.h>

#include <net/route.h>
#include <net/if.h>
#include <net/netisr2.h>

#define	_IP_VHL
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netinet/ip6.h>
#include <netinet/in_pcb.h>
#include <netinet6/in6_pcb.h>
#include <netinet/in_var.h>
#include <netinet/ip_var.h>
#include <netinet6/ip6_var.h>
#include <netinet/ip_icmp.h>
#ifdef INET6
#include <netinet/icmp6.h>
#endif
#include <netinet/tcp.h>
#include <netinet/tcp_fsm.h>
#include <netinet/tcp_seq.h>
#include <netinet/tcp_timer.h>
#include <netinet/tcp_timer2.h>
#include <netinet/tcp_var.h>
#include <netinet6/tcp6_var.h>
#include <netinet/tcpip.h>
#ifdef TCPDEBUG
#include <netinet/tcp_debug.h>
#endif
#include <netinet6/ip6protosw.h>

#include <sys/md5.h>
#include <machine/smp.h>

#include <sys/msgport2.h>
#include <net/netmsg2.h>

#if !defined(KTR_TCP)
#define KTR_TCP		KTR_ALL
#endif
/*
KTR_INFO_MASTER(tcp);
KTR_INFO(KTR_TCP, tcp, rxmsg, 0, "tcp getmsg", 0);
KTR_INFO(KTR_TCP, tcp, wait, 1, "tcp waitmsg", 0);
KTR_INFO(KTR_TCP, tcp, delayed, 2, "tcp execute delayed ops", 0);
#define logtcp(name)	KTR_LOG(tcp_ ## name)
*/

#define TCP_IW_MAXSEGS_DFLT	4
#define TCP_IW_CAPSEGS_DFLT	4

struct tcp_reass_pcpu {
	int			draining;
	struct netmsg_base	drain_nmsg;
} __cachealign;

struct inpcbinfo tcbinfo[MAXCPU];
struct tcpcbackq tcpcbackq[MAXCPU];
struct tcp_reass_pcpu tcp_reassq[MAXCPU];

int tcp_mssdflt = TCP_MSS;
SYSCTL_INT(_net_inet_tcp, TCPCTL_MSSDFLT, mssdflt, CTLFLAG_RW,
    &tcp_mssdflt, 0, "Default TCP Maximum Segment Size");

#ifdef INET6
int tcp_v6mssdflt = TCP6_MSS;
SYSCTL_INT(_net_inet_tcp, TCPCTL_V6MSSDFLT, v6mssdflt, CTLFLAG_RW,
    &tcp_v6mssdflt, 0, "Default TCP Maximum Segment Size for IPv6");
#endif

/*
 * Minimum MSS we accept and use. This prevents DoS attacks where
 * we are forced to a ridiculous low MSS like 20 and send hundreds
 * of packets instead of one. The effect scales with the available
 * bandwidth and quickly saturates the CPU and network interface
 * with packet generation and sending. Set to zero to disable MINMSS
 * checking. This setting prevents us from sending too small packets.
 */
int tcp_minmss = TCP_MINMSS;
SYSCTL_INT(_net_inet_tcp, OID_AUTO, minmss, CTLFLAG_RW,
    &tcp_minmss , 0, "Minmum TCP Maximum Segment Size");

#if 0
static int tcp_rttdflt = TCPTV_SRTTDFLT / PR_SLOWHZ;
SYSCTL_INT(_net_inet_tcp, TCPCTL_RTTDFLT, rttdflt, CTLFLAG_RW,
    &tcp_rttdflt, 0, "Default maximum TCP Round Trip Time");
#endif

int tcp_do_rfc1323 = 1;
SYSCTL_INT(_net_inet_tcp, TCPCTL_DO_RFC1323, rfc1323, CTLFLAG_RW,
    &tcp_do_rfc1323, 0, "Enable rfc1323 (high performance TCP) extensions");

static int tcp_tcbhashsize = 0;
SYSCTL_INT(_net_inet_tcp, OID_AUTO, tcbhashsize, CTLFLAG_RD,
     &tcp_tcbhashsize, 0, "Size of TCP control block hashtable");

static int do_tcpdrain = 1;
SYSCTL_INT(_net_inet_tcp, OID_AUTO, do_tcpdrain, CTLFLAG_RW, &do_tcpdrain, 0,
     "Enable tcp_drain routine for extra help when low on mbufs");

static int icmp_may_rst = 1;
SYSCTL_INT(_net_inet_tcp, OID_AUTO, icmp_may_rst, CTLFLAG_RW, &icmp_may_rst, 0,
    "Certain ICMP unreachable messages may abort connections in SYN_SENT");

/*
 * Recommend 20 (6 times in two minutes)
 *
 * Lower values may cause the sequence space to cycle too quickly and lose
 * its signed monotonically-increasing nature within the 2-minute TIMEDWAIT
 * window.
 */
static int tcp_isn_reseed_interval = 20;
SYSCTL_INT(_net_inet_tcp, OID_AUTO, isn_reseed_interval, CTLFLAG_RW,
    &tcp_isn_reseed_interval, 0, "Seconds between reseeding of ISN secret");

/*
 * TCP bandwidth limiting sysctls.  The inflight limiter is now turned on
 * by default, but with generous values which should allow maximal
 * bandwidth.  In particular, the slop defaults to 50 (5 packets).
 *
 * The reason for doing this is that the limiter is the only mechanism we
 * have which seems to do a really good job preventing receiver RX rings
 * on network interfaces from getting blown out.  Even though GigE/10GigE
 * is supposed to flow control it looks like either it doesn't actually
 * do it or Open Source drivers do not properly enable it.
 *
 * People using the limiter to reduce bottlenecks on slower WAN connections
 * should set the slop to 20 (2 packets).
 */
static int tcp_inflight_enable = 1;
SYSCTL_INT(_net_inet_tcp, OID_AUTO, inflight_enable, CTLFLAG_RW,
    &tcp_inflight_enable, 0, "Enable automatic TCP inflight data limiting");

static int tcp_inflight_debug = 0;
SYSCTL_INT(_net_inet_tcp, OID_AUTO, inflight_debug, CTLFLAG_RW,
    &tcp_inflight_debug, 0, "Debug TCP inflight calculations");

/*
 * NOTE: tcp_inflight_start is essentially the starting receive window
 *	 for a connection.  If set too low then fetches over tcp
 *	 connections will take noticably longer to ramp-up over
 *	 high-latency connections.  6144 is too low for a default,
 *	 use something more reasonable.
 */
static int tcp_inflight_start = 33792;
SYSCTL_INT(_net_inet_tcp, OID_AUTO, inflight_start, CTLFLAG_RW,
    &tcp_inflight_start, 0, "Start value for TCP inflight window");

static int tcp_inflight_min = 6144;
SYSCTL_INT(_net_inet_tcp, OID_AUTO, inflight_min, CTLFLAG_RW,
    &tcp_inflight_min, 0, "Lower bound for TCP inflight window");

static int tcp_inflight_max = TCP_MAXWIN << TCP_MAX_WINSHIFT;
SYSCTL_INT(_net_inet_tcp, OID_AUTO, inflight_max, CTLFLAG_RW,
    &tcp_inflight_max, 0, "Upper bound for TCP inflight window");

static int tcp_inflight_stab = 50;
SYSCTL_INT(_net_inet_tcp, OID_AUTO, inflight_stab, CTLFLAG_RW,
    &tcp_inflight_stab, 0, "Fudge bw 1/10% (50=5%)");

static int tcp_inflight_adjrtt = 2;
SYSCTL_INT(_net_inet_tcp, OID_AUTO, inflight_adjrtt, CTLFLAG_RW,
    &tcp_inflight_adjrtt, 0, "Slop for rtt 1/(hz*32)");

static int tcp_do_rfc3390 = 1;
SYSCTL_INT(_net_inet_tcp, OID_AUTO, rfc3390, CTLFLAG_RW,
    &tcp_do_rfc3390, 0,
    "Enable RFC 3390 (Increasing TCP's Initial Congestion Window)");

static u_long tcp_iw_maxsegs = TCP_IW_MAXSEGS_DFLT;
SYSCTL_ULONG(_net_inet_tcp, OID_AUTO, iwmaxsegs, CTLFLAG_RW,
    &tcp_iw_maxsegs, 0, "TCP IW segments max");

static u_long tcp_iw_capsegs = TCP_IW_CAPSEGS_DFLT;
SYSCTL_ULONG(_net_inet_tcp, OID_AUTO, iwcapsegs, CTLFLAG_RW,
    &tcp_iw_capsegs, 0, "TCP IW segments");

int tcp_low_rtobase = 1;
SYSCTL_INT(_net_inet_tcp, OID_AUTO, low_rtobase, CTLFLAG_RW,
    &tcp_low_rtobase, 0, "Lowering the Initial RTO (RFC 6298)");

static int tcp_do_ncr = 1;
SYSCTL_INT(_net_inet_tcp, OID_AUTO, ncr, CTLFLAG_RW,
    &tcp_do_ncr, 0, "Non-Congestion Robustness (RFC 4653)");

int tcp_ncr_linklocal = 0;
SYSCTL_INT(_net_inet_tcp, OID_AUTO, ncr_linklocal, CTLFLAG_RW,
    &tcp_ncr_linklocal, 0,
    "Enable Non-Congestion Robustness (RFC 4653) on link local network");

int tcp_ncr_rxtthresh_max = 16;
SYSCTL_INT(_net_inet_tcp, OID_AUTO, ncr_rxtthresh_max, CTLFLAG_RW,
    &tcp_ncr_rxtthresh_max, 0,
    "Non-Congestion Robustness (RFC 4653), DupThresh upper limit");

static MALLOC_DEFINE(M_TCPTEMP, "tcptemp", "TCP Templates for Keepalives");
static struct malloc_pipe tcptemp_mpipe;

static void tcp_willblock(void);
static void tcp_notify (struct inpcb *, int);

struct tcp_stats tcpstats_percpu[MAXCPU] __cachealign;
struct tcp_state_count tcpstate_count[MAXCPU] __cachealign;

static void	tcp_drain_dispatch(netmsg_t nmsg);

static int
sysctl_tcpstats(SYSCTL_HANDLER_ARGS)
{
	int cpu, error = 0;

	for (cpu = 0; cpu < netisr_ncpus; ++cpu) {
		if ((error = SYSCTL_OUT(req, &tcpstats_percpu[cpu],
					sizeof(struct tcp_stats))))
			break;
		if ((error = SYSCTL_IN(req, &tcpstats_percpu[cpu],
				       sizeof(struct tcp_stats))))
			break;
	}

	return (error);
}
SYSCTL_PROC(_net_inet_tcp, TCPCTL_STATS, stats, (CTLTYPE_OPAQUE | CTLFLAG_RW),
    0, 0, sysctl_tcpstats, "S,tcp_stats", "TCP statistics");

/*
 * Target size of TCP PCB hash tables. Must be a power of two.
 *
 * Note that this can be overridden by the kernel environment
 * variable net.inet.tcp.tcbhashsize
 */
#ifndef TCBHASHSIZE
#define	TCBHASHSIZE	512
#endif
CTASSERT(powerof2(TCBHASHSIZE));

/*
 * This is the actual shape of what we allocate using the zone
 * allocator.  Doing it this way allows us to protect both structures
 * using the same generation count, and also eliminates the overhead
 * of allocating tcpcbs separately.  By hiding the structure here,
 * we avoid changing most of the rest of the code (although it needs
 * to be changed, eventually, for greater efficiency).
 */
#define	ALIGNMENT	32
#define	ALIGNM1		(ALIGNMENT - 1)
struct	inp_tp {
	union {
		struct	inpcb inp;
		char	align[(sizeof(struct inpcb) + ALIGNM1) & ~ALIGNM1];
	} inp_tp_u;
	struct	tcpcb tcb;
	struct	tcp_callout inp_tp_rexmt;
	struct	tcp_callout inp_tp_persist;
	struct	tcp_callout inp_tp_keep;
	struct	tcp_callout inp_tp_2msl;
	struct	tcp_callout inp_tp_delack;
	struct	netmsg_tcp_timer inp_tp_timermsg;
	struct	netmsg_base inp_tp_sndmore;
};
#undef ALIGNMENT
#undef ALIGNM1

/*
 * Tcp initialization
 */
void
tcp_init(void)
{
	struct inpcbportinfo *portinfo;
	struct inpcbinfo *ticb;
	int hashsize = TCBHASHSIZE, portinfo_hsize;
	int cpu;

	/*
	 * note: tcptemp is used for keepalives, and it is ok for an
	 * allocation to fail so do not specify MPF_INT.
	 */
	mpipe_init(&tcptemp_mpipe, M_TCPTEMP, sizeof(struct tcptemp),
		    25, -1, 0, NULL, NULL, NULL);

	tcp_delacktime = TCPTV_DELACK;
	tcp_keepinit = TCPTV_KEEP_INIT;
	tcp_keepidle = TCPTV_KEEP_IDLE;
	tcp_keepintvl = TCPTV_KEEPINTVL;
	tcp_maxpersistidle = TCPTV_KEEP_IDLE;
	tcp_msl = TCPTV_MSL;
	tcp_rexmit_min = TCPTV_MIN;
	if (tcp_rexmit_min < 1) /* if kern.hz is too low */
		tcp_rexmit_min = 1;
	tcp_rexmit_slop = TCPTV_CPU_VAR;

	TUNABLE_INT_FETCH("net.inet.tcp.tcbhashsize", &hashsize);
	if (!powerof2(hashsize)) {
		kprintf("WARNING: TCB hash size not a power of 2\n");
		hashsize = TCBHASHSIZE; /* safe default */
	}
	tcp_tcbhashsize = hashsize;

	portinfo_hsize = 65536 / netisr_ncpus;
	if (portinfo_hsize > hashsize)
		portinfo_hsize = hashsize;

	portinfo = kmalloc(sizeof(*portinfo) * netisr_ncpus, M_PCB,
			   M_WAITOK | M_CACHEALIGN);

	for (cpu = 0; cpu < netisr_ncpus; cpu++) {
		ticb = &tcbinfo[cpu];
		in_pcbinfo_init(ticb, cpu, FALSE);
		ticb->hashbase = hashinit(hashsize, M_PCB,
					  &ticb->hashmask);
		in_pcbportinfo_init(&portinfo[cpu], portinfo_hsize, cpu);
		in_pcbportinfo_set(ticb, portinfo, netisr_ncpus);
		ticb->wildcardhashbase = hashinit(hashsize, M_PCB,
						  &ticb->wildcardhashmask);
		ticb->localgrphashbase = hashinit(hashsize, M_PCB,
						  &ticb->localgrphashmask);
		ticb->ipi_size = sizeof(struct inp_tp);
		TAILQ_INIT(&tcpcbackq[cpu].head);
	}

	tcp_reass_maxseg = nmbclusters / 16;
	TUNABLE_INT_FETCH("net.inet.tcp.reass.maxsegments", &tcp_reass_maxseg);

#ifdef INET6
#define	TCP_MINPROTOHDR (sizeof(struct ip6_hdr) + sizeof(struct tcphdr))
#else
#define	TCP_MINPROTOHDR (sizeof(struct tcpiphdr))
#endif
	if (max_protohdr < TCP_MINPROTOHDR)
		max_protohdr = TCP_MINPROTOHDR;
	if (max_linkhdr + TCP_MINPROTOHDR > MHLEN)
		panic("tcp_init");
#undef TCP_MINPROTOHDR

	/*
	 * Initialize TCP statistics counters for each CPU.
	 */
	for (cpu = 0; cpu < netisr_ncpus; ++cpu)
		bzero(&tcpstats_percpu[cpu], sizeof(struct tcp_stats));

	/*
	 * Initialize netmsgs for TCP drain
	 */
	for (cpu = 0; cpu < netisr_ncpus; ++cpu) {
		netmsg_init(&tcp_reassq[cpu].drain_nmsg, NULL,
		    &netisr_adone_rport, MSGF_PRIORITY, tcp_drain_dispatch);
	}

	syncache_init();
	netisr_register_rollup(tcp_willblock, NETISR_ROLLUP_PRIO_TCP);
}

static void
tcp_willblock(void)
{
	struct tcpcb *tp;
	int cpu = mycpuid;

	while ((tp = TAILQ_FIRST(&tcpcbackq[cpu].head)) != NULL) {
		KKASSERT(tp->t_flags & TF_ONOUTPUTQ);
		tp->t_flags &= ~TF_ONOUTPUTQ;
		TAILQ_REMOVE(&tcpcbackq[cpu].head, tp, t_outputq);
		tcp_output(tp);
	}
}

/*
 * Fill in the IP and TCP headers for an outgoing packet, given the tcpcb.
 * tcp_template used to store this data in mbufs, but we now recopy it out
 * of the tcpcb each time to conserve mbufs.
 */
void
tcp_fillheaders(struct tcpcb *tp, void *ip_ptr, void *tcp_ptr, boolean_t tso)
{
	struct inpcb *inp = tp->t_inpcb;
	struct tcphdr *tcp_hdr = (struct tcphdr *)tcp_ptr;

#ifdef INET6
	if (INP_ISIPV6(inp)) {
		struct ip6_hdr *ip6;

		ip6 = (struct ip6_hdr *)ip_ptr;
		ip6->ip6_flow = (ip6->ip6_flow & ~IPV6_FLOWINFO_MASK) |
			(inp->in6p_flowinfo & IPV6_FLOWINFO_MASK);
		ip6->ip6_vfc = (ip6->ip6_vfc & ~IPV6_VERSION_MASK) |
			(IPV6_VERSION & IPV6_VERSION_MASK);
		ip6->ip6_nxt = IPPROTO_TCP;
		ip6->ip6_plen = sizeof(struct tcphdr);
		ip6->ip6_src = inp->in6p_laddr;
		ip6->ip6_dst = inp->in6p_faddr;
		tcp_hdr->th_sum = 0;
	} else
#endif
	{
		struct ip *ip = (struct ip *) ip_ptr;
		u_int plen;

		ip->ip_vhl = IP_VHL_BORING;
		ip->ip_tos = 0;
		ip->ip_len = 0;
		ip->ip_id = 0;
		ip->ip_off = 0;
		ip->ip_ttl = 0;
		ip->ip_sum = 0;
		ip->ip_p = IPPROTO_TCP;
		ip->ip_src = inp->inp_laddr;
		ip->ip_dst = inp->inp_faddr;

		if (tso)
			plen = htons(IPPROTO_TCP);
		else
			plen = htons(sizeof(struct tcphdr) + IPPROTO_TCP);
		tcp_hdr->th_sum = in_pseudo(ip->ip_src.s_addr,
		    ip->ip_dst.s_addr, plen);
	}

	tcp_hdr->th_sport = inp->inp_lport;
	tcp_hdr->th_dport = inp->inp_fport;
	tcp_hdr->th_seq = 0;
	tcp_hdr->th_ack = 0;
	tcp_hdr->th_x2 = 0;
	tcp_hdr->th_off = 5;
	tcp_hdr->th_flags = 0;
	tcp_hdr->th_win = 0;
	tcp_hdr->th_urp = 0;
}

/*
 * Create template to be used to send tcp packets on a connection.
 * Allocates an mbuf and fills in a skeletal tcp/ip header.  The only
 * use for this function is in keepalives, which use tcp_respond.
 */
struct tcptemp *
tcp_maketemplate(struct tcpcb *tp)
{
	struct tcptemp *tmp;

	if ((tmp = mpipe_alloc_nowait(&tcptemp_mpipe)) == NULL)
		return (NULL);
	tcp_fillheaders(tp, &tmp->tt_ipgen, &tmp->tt_t, FALSE);
	return (tmp);
}

void
tcp_freetemplate(struct tcptemp *tmp)
{
	mpipe_free(&tcptemp_mpipe, tmp);
}

/*
 * Send a single message to the TCP at address specified by
 * the given TCP/IP header.  If m == NULL, then we make a copy
 * of the tcpiphdr at ti and send directly to the addressed host.
 * This is used to force keep alive messages out using the TCP
 * template for a connection.  If flags are given then we send
 * a message back to the TCP which originated the * segment ti,
 * and discard the mbuf containing it and any other attached mbufs.
 *
 * In any case the ack and sequence number of the transmitted
 * segment are as specified by the parameters.
 *
 * NOTE: If m != NULL, then ti must point to *inside* the mbuf.
 */
void
tcp_respond(struct tcpcb *tp, void *ipgen, struct tcphdr *th, struct mbuf *m,
	    tcp_seq ack, tcp_seq seq, int flags)
{
	int tlen;
	long win = 0;
	struct route *ro = NULL;
	struct route sro;
	struct ip *ip = ipgen;
	struct tcphdr *nth;
	int ipflags = 0;
	struct route_in6 *ro6 = NULL;
	struct route_in6 sro6;
	struct ip6_hdr *ip6 = ipgen;
	struct inpcb *inp = NULL;
	boolean_t use_tmpro = TRUE;
#ifdef INET6
	boolean_t isipv6 = (IP_VHL_V(ip->ip_vhl) == 6);
#else
	const boolean_t isipv6 = FALSE;
#endif

	if (tp != NULL) {
		inp = tp->t_inpcb;
		if (!(flags & TH_RST)) {
			win = ssb_space(&inp->inp_socket->so_rcv);
			if (win < 0)
				win = 0;
			if (win > (long)TCP_MAXWIN << tp->rcv_scale)
				win = (long)TCP_MAXWIN << tp->rcv_scale;
		}
		/*
		 * Don't use the route cache of a listen socket,
		 * it is not MPSAFE; use temporary route cache.
		 */
		if (tp->t_state != TCPS_LISTEN) {
			if (isipv6)
				ro6 = &inp->in6p_route;
			else
				ro = &inp->inp_route;
			use_tmpro = FALSE;
		}
	}
	if (use_tmpro) {
		if (isipv6) {
			ro6 = &sro6;
			bzero(ro6, sizeof *ro6);
		} else {
			ro = &sro;
			bzero(ro, sizeof *ro);
		}
	}
	if (m == NULL) {
		m = m_gethdr(M_NOWAIT, MT_HEADER);
		if (m == NULL)
			return;
		tlen = 0;
		m->m_data += max_linkhdr;
		if (isipv6) {
			bcopy(ip6, mtod(m, caddr_t), sizeof(struct ip6_hdr));
			ip6 = mtod(m, struct ip6_hdr *);
			nth = (struct tcphdr *)(ip6 + 1);
		} else {
			bcopy(ip, mtod(m, caddr_t), sizeof(struct ip));
			ip = mtod(m, struct ip *);
			nth = (struct tcphdr *)(ip + 1);
		}
		bcopy(th, nth, sizeof(struct tcphdr));
		flags = TH_ACK;
	} else {
		m_freem(m->m_next);
		m->m_next = NULL;
		m->m_data = (caddr_t)ipgen;
		/* m_len is set later */
		tlen = 0;
#define	xchg(a, b, type) { type t; t = a; a = b; b = t; }
		if (isipv6) {
			xchg(ip6->ip6_dst, ip6->ip6_src, struct in6_addr);
			nth = (struct tcphdr *)(ip6 + 1);
		} else {
			xchg(ip->ip_dst.s_addr, ip->ip_src.s_addr, n_long);
			nth = (struct tcphdr *)(ip + 1);
		}
		if (th != nth) {
			/*
			 * this is usually a case when an extension header
			 * exists between the IPv6 header and the
			 * TCP header.
			 */
			nth->th_sport = th->th_sport;
			nth->th_dport = th->th_dport;
		}
		xchg(nth->th_dport, nth->th_sport, n_short);
#undef xchg
	}
	if (isipv6) {
		ip6->ip6_flow = 0;
		ip6->ip6_vfc = IPV6_VERSION;
		ip6->ip6_nxt = IPPROTO_TCP;
		ip6->ip6_plen = htons((u_short)(sizeof(struct tcphdr) + tlen));
		tlen += sizeof(struct ip6_hdr) + sizeof(struct tcphdr);
	} else {
		tlen += sizeof(struct tcpiphdr);
		ip->ip_len = htons(tlen);
		ip->ip_ttl = ip_defttl;
	}
	m->m_len = tlen;
	m->m_pkthdr.len = tlen;
	m->m_pkthdr.rcvif = NULL;
	nth->th_seq = htonl(seq);
	nth->th_ack = htonl(ack);
	nth->th_x2 = 0;
	nth->th_off = sizeof(struct tcphdr) >> 2;
	nth->th_flags = flags;
	if (tp != NULL)
		nth->th_win = htons((u_short) (win >> tp->rcv_scale));
	else
		nth->th_win = htons((u_short)win);
	nth->th_urp = 0;
	if (isipv6) {
		nth->th_sum = 0;
		nth->th_sum = in6_cksum(m, IPPROTO_TCP,
					sizeof(struct ip6_hdr),
					tlen - sizeof(struct ip6_hdr));
		ip6->ip6_hlim = in6_selecthlim(inp,
		    (ro6 && ro6->ro_rt) ? ro6->ro_rt->rt_ifp : NULL);
	} else {
		nth->th_sum = in_pseudo(ip->ip_src.s_addr, ip->ip_dst.s_addr,
		    htons((u_short)(tlen - sizeof(struct ip) + ip->ip_p)));
		m->m_pkthdr.csum_flags = CSUM_TCP;
		m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum);
		m->m_pkthdr.csum_thlen = sizeof(struct tcphdr);
	}
#ifdef TCPDEBUG
	if (tp == NULL || (inp->inp_socket->so_options & SO_DEBUG))
		tcp_trace(TA_OUTPUT, 0, tp, mtod(m, void *), th, 0);
#endif
	if (isipv6) {
		ip6_output(m, NULL, ro6, ipflags, NULL, NULL, inp);
		if ((ro6 == &sro6) && (ro6->ro_rt != NULL)) {
			RTFREE(ro6->ro_rt);
			ro6->ro_rt = NULL;
		}
	} else {
		if (inp != NULL && (inp->inp_flags & INP_HASH))
			m_sethash(m, inp->inp_hashval);
		ipflags |= IP_DEBUGROUTE;
		ip_output(m, NULL, ro, ipflags, NULL, inp);
		if ((ro == &sro) && (ro->ro_rt != NULL)) {
			RTFREE(ro->ro_rt);
			ro->ro_rt = NULL;
		}
	}
}

/*
 * Create a new TCP control block, making an
 * empty reassembly queue and hooking it to the argument
 * protocol control block.  The `inp' parameter must have
 * come from the zone allocator set up in tcp_init().
 */
void
tcp_newtcpcb(struct inpcb *inp)
{
	struct inp_tp *it;
	struct tcpcb *tp;
#ifdef INET6
	boolean_t isipv6 = INP_ISIPV6(inp);
#else
	const boolean_t isipv6 = FALSE;
#endif

	it = (struct inp_tp *)inp;
	tp = &it->tcb;
	bzero(tp, sizeof(struct tcpcb));
	TAILQ_INIT(&tp->t_segq);
	tp->t_maxseg = tp->t_maxopd = isipv6 ? tcp_v6mssdflt : tcp_mssdflt;
	tp->t_rxtthresh = tcprexmtthresh;

	/* Set up our timeouts. */
	tp->tt_rexmt = &it->inp_tp_rexmt;
	tp->tt_persist = &it->inp_tp_persist;
	tp->tt_keep = &it->inp_tp_keep;
	tp->tt_2msl = &it->inp_tp_2msl;
	tp->tt_delack = &it->inp_tp_delack;
	tcp_inittimers(tp);

	/*
	 * Zero out timer message.  We don't create it here,
	 * since the current CPU may not be the owner of this
	 * inpcb.
	 */
	tp->tt_msg = &it->inp_tp_timermsg;
	bzero(tp->tt_msg, sizeof(*tp->tt_msg));

	tp->t_keepinit = tcp_keepinit;
	tp->t_keepidle = tcp_keepidle;
	tp->t_keepintvl = tcp_keepintvl;
	tp->t_keepcnt = tcp_keepcnt;
	tp->t_maxidle = tp->t_keepintvl * tp->t_keepcnt;

	if (tcp_do_ncr)
		tp->t_flags |= TF_NCR;
	if (tcp_do_rfc1323)
		tp->t_flags |= (TF_REQ_SCALE | TF_REQ_TSTMP);

	tp->t_inpcb = inp;	/* XXX */
	TCP_STATE_INIT(tp);
	/*
	 * Init srtt to TCPTV_SRTTBASE (0), so we can tell that we have no
	 * rtt estimate.  Set rttvar so that srtt + 4 * rttvar gives
	 * reasonable initial retransmit time.
	 */
	tp->t_srtt = TCPTV_SRTTBASE;
	tp->t_rttvar =
	    ((TCPTV_RTOBASE - TCPTV_SRTTBASE) << TCP_RTTVAR_SHIFT) / 4;
	tp->t_rttmin = tcp_rexmit_min;
	tp->t_rxtcur = TCPTV_RTOBASE;
	tp->snd_cwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT;
	tp->snd_bwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT;
	tp->snd_ssthresh = TCP_MAXWIN << TCP_MAX_WINSHIFT;
	tp->snd_last = ticks;
	tp->t_rcvtime = ticks;
	/*
	 * IPv4 TTL initialization is necessary for an IPv6 socket as well,
	 * because the socket may be bound to an IPv6 wildcard address,
	 * which may match an IPv4-mapped IPv6 address.
	 */
	inp->inp_ip_ttl = ip_defttl;
	inp->inp_ppcb = tp;
	tcp_sack_tcpcb_init(tp);

	tp->tt_sndmore = &it->inp_tp_sndmore;
	tcp_output_init(tp);
}

/*
 * Drop a TCP connection, reporting the specified error.
 * If connection is synchronized, then send a RST to peer.
 */
struct tcpcb *
tcp_drop(struct tcpcb *tp, int error)
{
	struct socket *so = tp->t_inpcb->inp_socket;

	if (TCPS_HAVERCVDSYN(tp->t_state)) {
		TCP_STATE_CHANGE(tp, TCPS_CLOSED);
		tcp_output(tp);
		tcpstat.tcps_drops++;
	} else
		tcpstat.tcps_conndrops++;
	if (error == ETIMEDOUT && tp->t_softerror)
		error = tp->t_softerror;
	so->so_error = error;
	return (tcp_close(tp));
}

struct netmsg_listen_detach {
	struct netmsg_base	base;
	struct tcpcb		*nm_tp;
	struct tcpcb		*nm_tp_inh;
};

static void
tcp_listen_detach_handler(netmsg_t msg)
{
	struct netmsg_listen_detach *nmsg = (struct netmsg_listen_detach *)msg;
	struct tcpcb *tp = nmsg->nm_tp;
	int cpu = mycpuid, nextcpu;

	if (tp->t_flags & TF_LISTEN) {
		syncache_destroy(tp, nmsg->nm_tp_inh);
		tcp_pcbport_merge_oncpu(tp);
	}

	in_pcbremwildcardhash_oncpu(tp->t_inpcb, &tcbinfo[cpu]);

	nextcpu = cpu + 1;
	if (nextcpu < netisr_ncpus)
		lwkt_forwardmsg(netisr_cpuport(nextcpu), &nmsg->base.lmsg);
	else
		lwkt_replymsg(&nmsg->base.lmsg, 0);
}

/*
 * Close a TCP control block:
 *	discard all space held by the tcp
 *	discard internet protocol block
 *	wake up any sleepers
 */
struct tcpcb *
tcp_close(struct tcpcb *tp)
{
	struct tseg_qent *q;
	struct inpcb *inp = tp->t_inpcb;
	struct inpcb *inp_inh = NULL;
	struct tcpcb *tp_inh = NULL;
	struct socket *so = inp->inp_socket;
	struct rtentry *rt;
	boolean_t dosavessthresh;
#ifdef INET6
	boolean_t isipv6 = INP_ISIPV6(inp);
#else
	const boolean_t isipv6 = FALSE;
#endif

	if (tp->t_flags & TF_LISTEN) {
		/*
		 * Pending socket/syncache inheritance
		 *
		 * If this is a listen(2) socket, find another listen(2)
		 * socket in the same local group, which could inherit
		 * the syncache and sockets pending on the completion
		 * and incompletion queues.
		 *
		 * NOTE:
		 * Currently the inheritance could only happen on the
		 * listen(2) sockets w/ SO_REUSEPORT set.
		 */
		ASSERT_NETISR0;
		inp_inh = in_pcblocalgroup_last(&tcbinfo[0], inp);
		if (inp_inh != NULL)
			tp_inh = intotcpcb(inp_inh);
	}

	/*
	 * INP_WILDCARD indicates that listen(2) has been called on
	 * this socket.  This implies:
	 * - A wildcard inp's hash is replicated for each protocol thread.
	 * - Syncache for this inp grows independently in each protocol
	 *   thread.
	 * - There is more than one cpu
	 *
	 * We have to chain a message to the rest of the protocol threads
	 * to cleanup the wildcard hash and the syncache.  The cleanup
	 * in the current protocol thread is defered till the end of this
	 * function (syncache_destroy and in_pcbdetach).
	 *
	 * NOTE:
	 * After cleanup the inp's hash and syncache entries, this inp will
	 * no longer be available to the rest of the protocol threads, so we
	 * are safe to whack the inp in the following code.
	 */
	if ((inp->inp_flags & INP_WILDCARD) && netisr_ncpus > 1) {
		struct netmsg_listen_detach nmsg;

		KKASSERT(so->so_port == netisr_cpuport(0));
		ASSERT_NETISR0;
		KKASSERT(inp->inp_pcbinfo == &tcbinfo[0]);

		netmsg_init(&nmsg.base, NULL, &curthread->td_msgport,
			    MSGF_PRIORITY, tcp_listen_detach_handler);
		nmsg.nm_tp = tp;
		nmsg.nm_tp_inh = tp_inh;
		lwkt_domsg(netisr_cpuport(1), &nmsg.base.lmsg, 0);
	}

	TCP_STATE_TERM(tp);

	/*
	 * Make sure that all of our timers are stopped before we
	 * delete the PCB.  For listen TCP socket (tp->tt_msg == NULL),
	 * timers are never used.  If timer message is never created
	 * (tp->tt_msg->tt_tcb == NULL), timers are never used too.
	 */
	if (tp->tt_msg != NULL && tp->tt_msg->tt_tcb != NULL) {
		tcp_callout_terminate(tp, tp->tt_rexmt);
		tcp_callout_terminate(tp, tp->tt_persist);
		tcp_callout_terminate(tp, tp->tt_keep);
		tcp_callout_terminate(tp, tp->tt_2msl);
		tcp_callout_terminate(tp, tp->tt_delack);
	}

	if (tp->t_flags & TF_ONOUTPUTQ) {
		KKASSERT(tp->tt_cpu == mycpu->gd_cpuid);
		TAILQ_REMOVE(&tcpcbackq[tp->tt_cpu].head, tp, t_outputq);
		tp->t_flags &= ~TF_ONOUTPUTQ;
	}

	/*
	 * If we got enough samples through the srtt filter,
	 * save the rtt and rttvar in the routing entry.
	 * 'Enough' is arbitrarily defined as the 16 samples.
	 * 16 samples is enough for the srtt filter to converge
	 * to within 5% of the correct value; fewer samples and
	 * we could save a very bogus rtt.
	 *
	 * Don't update the default route's characteristics and don't
	 * update anything that the user "locked".
	 */
	if (tp->t_rttupdated >= 16) {
		u_long i = 0;

		if (isipv6) {
			struct sockaddr_in6 *sin6;

			if ((rt = inp->in6p_route.ro_rt) == NULL)
				goto no_valid_rt;
			sin6 = (struct sockaddr_in6 *)rt_key(rt);
			if (IN6_IS_ADDR_UNSPECIFIED(&sin6->sin6_addr))
				goto no_valid_rt;
		} else
			if ((rt = inp->inp_route.ro_rt) == NULL ||
			    ((struct sockaddr_in *)rt_key(rt))->
			     sin_addr.s_addr == INADDR_ANY)
				goto no_valid_rt;

		if (!(rt->rt_rmx.rmx_locks & RTV_RTT)) {
			i = tp->t_srtt * (RTM_RTTUNIT / (hz * TCP_RTT_SCALE));
			if (rt->rt_rmx.rmx_rtt && i)
				/*
				 * filter this update to half the old & half
				 * the new values, converting scale.
				 * See route.h and tcp_var.h for a
				 * description of the scaling constants.
				 */
				rt->rt_rmx.rmx_rtt =
				    (rt->rt_rmx.rmx_rtt + i) / 2;
			else
				rt->rt_rmx.rmx_rtt = i;
			tcpstat.tcps_cachedrtt++;
		}
		if (!(rt->rt_rmx.rmx_locks & RTV_RTTVAR)) {
			i = tp->t_rttvar *
			    (RTM_RTTUNIT / (hz * TCP_RTTVAR_SCALE));
			if (rt->rt_rmx.rmx_rttvar && i)
				rt->rt_rmx.rmx_rttvar =
				    (rt->rt_rmx.rmx_rttvar + i) / 2;
			else
				rt->rt_rmx.rmx_rttvar = i;
			tcpstat.tcps_cachedrttvar++;
		}
		/*
		 * The old comment here said:
		 * update the pipelimit (ssthresh) if it has been updated
		 * already or if a pipesize was specified & the threshhold
		 * got below half the pipesize.  I.e., wait for bad news
		 * before we start updating, then update on both good
		 * and bad news.
		 *
		 * But we want to save the ssthresh even if no pipesize is
		 * specified explicitly in the route, because such
		 * connections still have an implicit pipesize specified
		 * by the global tcp_sendspace.  In the absence of a reliable
		 * way to calculate the pipesize, it will have to do.
		 */
		i = tp->snd_ssthresh;
		if (rt->rt_rmx.rmx_sendpipe != 0)
			dosavessthresh = (i < rt->rt_rmx.rmx_sendpipe/2);
		else
			dosavessthresh = (i < so->so_snd.ssb_hiwat/2);
		if (dosavessthresh ||
		    (!(rt->rt_rmx.rmx_locks & RTV_SSTHRESH) && (i != 0) &&
		     (rt->rt_rmx.rmx_ssthresh != 0))) {
			/*
			 * convert the limit from user data bytes to
			 * packets then to packet data bytes.
			 */
			i = (i + tp->t_maxseg / 2) / tp->t_maxseg;
			if (i < 2)
				i = 2;
			i *= tp->t_maxseg +
			     (isipv6 ?
			      sizeof(struct ip6_hdr) + sizeof(struct tcphdr) :
			      sizeof(struct tcpiphdr));
			if (rt->rt_rmx.rmx_ssthresh)
				rt->rt_rmx.rmx_ssthresh =
				    (rt->rt_rmx.rmx_ssthresh + i) / 2;
			else
				rt->rt_rmx.rmx_ssthresh = i;
			tcpstat.tcps_cachedssthresh++;
		}
	}

no_valid_rt:
	/* free the reassembly queue, if any */
	while((q = TAILQ_FIRST(&tp->t_segq)) != NULL) {
		TAILQ_REMOVE(&tp->t_segq, q, tqe_q);
		m_freem(q->tqe_m);
		kfree(q, M_TSEGQ);
		atomic_add_int(&tcp_reass_qsize, -1);
	}
	/* throw away SACK blocks in scoreboard*/
	if (TCP_DO_SACK(tp))
		tcp_sack_destroy(&tp->scb);

	inp->inp_ppcb = NULL;
	soisdisconnected(so);
	/* note: pcb detached later on */

	tcp_destroy_timermsg(tp);
	tcp_output_cancel(tp);

	if (tp->t_flags & TF_LISTEN) {
		syncache_destroy(tp, tp_inh);
		tcp_pcbport_merge_oncpu(tp);
		tcp_pcbport_destroy(tp);
		if (inp_inh != NULL && inp_inh->inp_socket != NULL) {
			/*
			 * Pending sockets inheritance only needs
			 * to be done once in the current thread,
			 * i.e. netisr0.
			 */
			soinherit(so, inp_inh->inp_socket);
		}
	}
	KASSERT(tp->t_pcbport == NULL, ("tcpcb port cache is not destroyed"));

	so_async_rcvd_drop(so);
	/* Drop the reference for the asynchronized pru_rcvd */
	sofree(so);

	/*
	 * NOTE:
	 * - Remove self from listen tcpcb per-cpu port cache _before_
	 *   pcbdetach.
	 * - pcbdetach removes any wildcard hash entry on the current CPU.
	 */
	tcp_pcbport_remove(inp);
#ifdef INET6
	if (isipv6)
		in6_pcbdetach(inp);
	else
#endif
		in_pcbdetach(inp);

	tcpstat.tcps_closed++;
	return (NULL);
}

/*
 * Walk the tcpbs, if existing, and flush the reassembly queue,
 * if there is one...
 */
static void
tcp_drain_oncpu(struct inpcbinfo *pcbinfo)
{
	struct inpcbhead *head = &pcbinfo->pcblisthead;
	struct inpcb *inpb;

	/*
	 * Since we run in netisr, it is MP safe, even if
	 * we block during the inpcb list iteration, i.e.
	 * we don't need to use inpcb marker here.
	 */
	ASSERT_NETISR_NCPUS(pcbinfo->cpu);

	LIST_FOREACH(inpb, head, inp_list) {
		struct tcpcb *tcpb;
		struct tseg_qent *te;

		if (inpb->inp_flags & INP_PLACEMARKER)
			continue;

		tcpb = intotcpcb(inpb);
		KASSERT(tcpb != NULL, ("tcp_drain_oncpu: tcpb is NULL"));

		if ((te = TAILQ_FIRST(&tcpb->t_segq)) != NULL) {
			TAILQ_REMOVE(&tcpb->t_segq, te, tqe_q);
			if (te->tqe_th->th_flags & TH_FIN)
				tcpb->t_flags &= ~TF_QUEDFIN;
			m_freem(te->tqe_m);
			kfree(te, M_TSEGQ);
			atomic_add_int(&tcp_reass_qsize, -1);
			/* retry */
		}
	}
}

static void
tcp_drain_dispatch(netmsg_t nmsg)
{
	crit_enter();
	lwkt_replymsg(&nmsg->lmsg, 0);  /* reply ASAP */
	crit_exit();

	tcp_drain_oncpu(&tcbinfo[mycpuid]);
	tcp_reassq[mycpuid].draining = 0;
}

static void
tcp_drain_ipi(void *arg __unused)
{
	int cpu = mycpuid;
	struct lwkt_msg *msg = &tcp_reassq[cpu].drain_nmsg.lmsg;

	crit_enter();
	if (msg->ms_flags & MSGF_DONE)
		lwkt_sendmsg_oncpu(netisr_cpuport(cpu), msg);
	crit_exit();
}

void
tcp_drain(void)
{
	cpumask_t mask;
	int cpu;

	if (!do_tcpdrain)
		return;

	if (tcp_reass_qsize == 0)
		return;

	CPUMASK_ASSBMASK(mask, netisr_ncpus);
	CPUMASK_ANDMASK(mask, smp_active_mask);

	cpu = mycpuid;
	if (IN_NETISR_NCPUS(cpu)) {
		tcp_drain_oncpu(&tcbinfo[cpu]);
		CPUMASK_NANDBIT(mask, cpu);
	}

	if (tcp_reass_qsize < netisr_ncpus) {
		/* Does not worth the trouble. */
		return;
	}

	for (cpu = 0; cpu < netisr_ncpus; ++cpu) {
		if (!CPUMASK_TESTBIT(mask, cpu))
			continue;

		if (tcp_reassq[cpu].draining) {
			/* Draining; skip this cpu. */
			CPUMASK_NANDBIT(mask, cpu);
			continue;
		}
		tcp_reassq[cpu].draining = 1;
	}

	if (CPUMASK_TESTNZERO(mask))
		lwkt_send_ipiq_mask(mask, tcp_drain_ipi, NULL);
}

/*
 * Notify a tcp user of an asynchronous error;
 * store error as soft error, but wake up user
 * (for now, won't do anything until can select for soft error).
 *
 * Do not wake up user since there currently is no mechanism for
 * reporting soft errors (yet - a kqueue filter may be added).
 */
static void
tcp_notify(struct inpcb *inp, int error)
{
	struct tcpcb *tp = intotcpcb(inp);

	/*
	 * Ignore some errors if we are hooked up.
	 * If connection hasn't completed, has retransmitted several times,
	 * and receives a second error, give up now.  This is better
	 * than waiting a long time to establish a connection that
	 * can never complete.
	 */
	if (tp->t_state == TCPS_ESTABLISHED &&
	     (error == EHOSTUNREACH || error == ENETUNREACH ||
	      error == EHOSTDOWN)) {
		return;
	} else if (tp->t_state < TCPS_ESTABLISHED && tp->t_rxtshift > 3 &&
	    tp->t_softerror)
		tcp_drop(tp, error);
	else
		tp->t_softerror = error;
#if 0
	wakeup(&so->so_timeo);
	sorwakeup(so);
	sowwakeup(so);
#endif
}

static int
tcp_pcblist(SYSCTL_HANDLER_ARGS)
{
	int error, i, n;
	struct inpcb *marker;
	struct inpcb *inp;
	int origcpu, ccpu;

	error = 0;
	n = 0;

	/*
	 * The process of preparing the TCB list is too time-consuming and
	 * resource-intensive to repeat twice on every request.
	 */
	if (req->oldptr == NULL) {
		for (ccpu = 0; ccpu < netisr_ncpus; ++ccpu)
			n += tcbinfo[ccpu].ipi_count;
		req->oldidx = (n + n/8 + 10) * sizeof(struct xtcpcb);
		return (0);
	}

	if (req->newptr != NULL)
		return (EPERM);

	marker = kmalloc(sizeof(struct inpcb), M_TEMP, M_WAITOK|M_ZERO);
	marker->inp_flags |= INP_PLACEMARKER;

	/*
	 * OK, now we're committed to doing something.  Run the inpcb list
	 * for each cpu in the system and construct the output.  Use a
	 * list placemarker to deal with list changes occuring during
	 * copyout blockages (but otherwise depend on being on the correct
	 * cpu to avoid races).
	 */
	origcpu = mycpu->gd_cpuid;
	for (ccpu = 0; ccpu < netisr_ncpus && error == 0; ++ccpu) {
		caddr_t inp_ppcb;
		struct xtcpcb xt;

		lwkt_migratecpu(ccpu);

		n = tcbinfo[ccpu].ipi_count;

		LIST_INSERT_HEAD(&tcbinfo[ccpu].pcblisthead, marker, inp_list);
		i = 0;
		while ((inp = LIST_NEXT(marker, inp_list)) != NULL && i < n) {
			/*
			 * process a snapshot of pcbs, ignoring placemarkers
			 * and using our own to allow SYSCTL_OUT to block.
			 */
			LIST_REMOVE(marker, inp_list);
			LIST_INSERT_AFTER(inp, marker, inp_list);

			if (inp->inp_flags & INP_PLACEMARKER)
				continue;
			if (prison_xinpcb(req->td, inp))
				continue;

			xt.xt_len = sizeof xt;
			bcopy(inp, &xt.xt_inp, sizeof *inp);
			inp_ppcb = inp->inp_ppcb;
			if (inp_ppcb != NULL)
				bcopy(inp_ppcb, &xt.xt_tp, sizeof xt.xt_tp);
			else
				bzero(&xt.xt_tp, sizeof xt.xt_tp);
			if (inp->inp_socket)
				sotoxsocket(inp->inp_socket, &xt.xt_socket);
			if ((error = SYSCTL_OUT(req, &xt, sizeof xt)) != 0)
				break;
			++i;
		}
		LIST_REMOVE(marker, inp_list);
		if (error == 0 && i < n) {
			bzero(&xt, sizeof xt);
			xt.xt_len = sizeof xt;
			while (i < n) {
				error = SYSCTL_OUT(req, &xt, sizeof xt);
				if (error)
					break;
				++i;
			}
		}
	}

	/*
	 * Make sure we are on the same cpu we were on originally, since
	 * higher level callers expect this.  Also don't pollute caches with
	 * migrated userland data by (eventually) returning to userland
	 * on a different cpu.
	 */
	lwkt_migratecpu(origcpu);
	kfree(marker, M_TEMP);
	return (error);
}

SYSCTL_PROC(_net_inet_tcp, TCPCTL_PCBLIST, pcblist, CTLFLAG_RD, 0, 0,
	    tcp_pcblist, "S,xtcpcb", "List of active TCP connections");

static int
tcp_getcred(SYSCTL_HANDLER_ARGS)
{
	struct sockaddr_in addrs[2];
	struct ucred cred0, *cred = NULL;
	struct inpcb *inp;
	int cpu, origcpu, error;

	error = caps_priv_check_td(req->td, SYSCAP_RESTRICTEDROOT);
	if (error != 0)
		return (error);
	error = SYSCTL_IN(req, addrs, sizeof addrs);
	if (error != 0)
		return (error);

	origcpu = mycpuid;
	cpu = tcp_addrcpu(addrs[1].sin_addr.s_addr, addrs[1].sin_port,
	    addrs[0].sin_addr.s_addr, addrs[0].sin_port);

	lwkt_migratecpu(cpu);

	inp = in_pcblookup_hash(&tcbinfo[cpu], addrs[1].sin_addr,
	    addrs[1].sin_port, addrs[0].sin_addr, addrs[0].sin_port, 0, NULL);
	if (inp == NULL || inp->inp_socket == NULL) {
		error = ENOENT;
	} else if (inp->inp_socket->so_cred != NULL) {
		cred0 = *(inp->inp_socket->so_cred);
		cred = &cred0;
	}

	lwkt_migratecpu(origcpu);

	if (error)
		return (error);

	return SYSCTL_OUT(req, cred, sizeof(struct ucred));
}

SYSCTL_PROC(_net_inet_tcp, OID_AUTO, getcred, (CTLTYPE_OPAQUE | CTLFLAG_RW),
    0, 0, tcp_getcred, "S,ucred", "Get the ucred of a TCP connection");

#ifdef INET6
static int
tcp6_getcred(SYSCTL_HANDLER_ARGS)
{
	struct sockaddr_in6 addrs[2];
	struct inpcb *inp;
	int error;

	error = caps_priv_check_td(req->td, SYSCAP_RESTRICTEDROOT);
	if (error != 0)
		return (error);
	error = SYSCTL_IN(req, addrs, sizeof addrs);
	if (error != 0)
		return (error);
	crit_enter();
	inp = in6_pcblookup_hash(&tcbinfo[0],
	    &addrs[1].sin6_addr, addrs[1].sin6_port,
	    &addrs[0].sin6_addr, addrs[0].sin6_port, 0, NULL);
	if (inp == NULL || inp->inp_socket == NULL) {
		error = ENOENT;
		goto out;
	}
	error = SYSCTL_OUT(req, inp->inp_socket->so_cred, sizeof(struct ucred));
out:
	crit_exit();
	return (error);
}

SYSCTL_PROC(_net_inet6_tcp6, OID_AUTO, getcred, (CTLTYPE_OPAQUE | CTLFLAG_RW),
	    0, 0,
	    tcp6_getcred, "S,ucred", "Get the ucred of a TCP6 connection");
#endif

struct netmsg_tcp_notify {
	struct netmsg_base base;
	inp_notify_t	nm_notify;
	struct in_addr	nm_faddr;
	int		nm_arg;
};

static void
tcp_notifyall_oncpu(netmsg_t msg)
{
	struct netmsg_tcp_notify *nm = (struct netmsg_tcp_notify *)msg;
	int nextcpu;

	ASSERT_NETISR_NCPUS(mycpuid);

	in_pcbnotifyall(&tcbinfo[mycpuid], nm->nm_faddr,
			nm->nm_arg, nm->nm_notify);

	nextcpu = mycpuid + 1;
	if (nextcpu < netisr_ncpus)
		lwkt_forwardmsg(netisr_cpuport(nextcpu), &nm->base.lmsg);
	else
		lwkt_replymsg(&nm->base.lmsg, 0);
}

inp_notify_t
tcp_get_inpnotify(int cmd, const struct sockaddr *sa,
    int *arg, struct ip **ip0, int *cpuid)
{
	struct ip *ip = *ip0;
	struct in_addr faddr;
	inp_notify_t notify = tcp_notify;

	faddr = ((const struct sockaddr_in *)sa)->sin_addr;
	if (sa->sa_family != AF_INET || faddr.s_addr == INADDR_ANY)
		return NULL;

	*arg = inetctlerrmap[cmd];
	if (cmd == PRC_QUENCH) {
		notify = tcp_quench;
	} else if (icmp_may_rst &&
		   (cmd == PRC_UNREACH_ADMIN_PROHIB ||
		    cmd == PRC_UNREACH_PORT ||
		    cmd == PRC_TIMXCEED_INTRANS) &&
		   ip != NULL) {
		notify = tcp_drop_syn_sent;
	} else if (cmd == PRC_MSGSIZE) {
		const struct icmp *icmp = (const struct icmp *)
		    ((caddr_t)ip - offsetof(struct icmp, icmp_ip));

		*arg = ntohs(icmp->icmp_nextmtu);
		notify = tcp_mtudisc;
	} else if (PRC_IS_REDIRECT(cmd)) {
		ip = NULL;
		notify = in_rtchange;
	} else if (cmd == PRC_HOSTDEAD) {
		ip = NULL;
	} else if ((unsigned)cmd >= PRC_NCMDS || inetctlerrmap[cmd] == 0) {
		return NULL;
	}

	if (cpuid != NULL) {
		if (ip == NULL) {
			/* Go through all effective netisr CPUs. */
			*cpuid = netisr_ncpus;
		} else {
			const struct tcphdr *th;

			th = (const struct tcphdr *)
			    ((caddr_t)ip + (IP_VHL_HL(ip->ip_vhl) << 2));
			*cpuid = tcp_addrcpu(faddr.s_addr, th->th_dport,
			    ip->ip_src.s_addr, th->th_sport);
		}
	}

	*ip0 = ip;
	return notify;
}

void
tcp_ctlinput(netmsg_t msg)
{
	int cmd = msg->ctlinput.nm_cmd;
	struct sockaddr *sa = msg->ctlinput.nm_arg;
	struct ip *ip = msg->ctlinput.nm_extra;
	struct in_addr faddr;
	inp_notify_t notify;
	int arg, cpuid;

	ASSERT_NETISR_NCPUS(mycpuid);

	notify = tcp_get_inpnotify(cmd, sa, &arg, &ip, &cpuid);
	if (notify == NULL)
		goto done;

	faddr = ((struct sockaddr_in *)sa)->sin_addr;
	if (ip != NULL) {
		const struct tcphdr *th;
		struct inpcb *inp;

		if (cpuid != mycpuid)
			goto done;

		th = (const struct tcphdr *)
		    ((caddr_t)ip + (IP_VHL_HL(ip->ip_vhl) << 2));
		inp = in_pcblookup_hash(&tcbinfo[mycpuid], faddr, th->th_dport,
					ip->ip_src, th->th_sport, 0, NULL);
		if (inp != NULL && inp->inp_socket != NULL) {
			tcp_seq icmpseq = htonl(th->th_seq);
			struct tcpcb *tp = intotcpcb(inp);

			if (SEQ_GEQ(icmpseq, tp->snd_una) &&
			    SEQ_LT(icmpseq, tp->snd_max))
				notify(inp, arg);
		} else {
			struct in_conninfo inc;

			inc.inc_fport = th->th_dport;
			inc.inc_lport = th->th_sport;
			inc.inc_faddr = faddr;
			inc.inc_laddr = ip->ip_src;
#ifdef INET6
			inc.inc_isipv6 = 0;
#endif
			syncache_unreach(&inc, th);
		}
	} else if (msg->ctlinput.nm_direct) {
		if (cpuid != netisr_ncpus && cpuid != mycpuid)
			goto done;

		in_pcbnotifyall(&tcbinfo[mycpuid], faddr, arg, notify);
	} else {
		struct netmsg_tcp_notify *nm;

		ASSERT_NETISR0;
		nm = kmalloc(sizeof(*nm), M_LWKTMSG, M_INTWAIT);
		netmsg_init(&nm->base, NULL, &netisr_afree_rport,
			    0, tcp_notifyall_oncpu);
		nm->nm_faddr = faddr;
		nm->nm_arg = arg;
		nm->nm_notify = notify;

		lwkt_sendmsg(netisr_cpuport(0), &nm->base.lmsg);
	}
done:
	lwkt_replymsg(&msg->lmsg, 0);
}

#ifdef INET6

void
tcp6_ctlinput(netmsg_t msg)
{
	int cmd = msg->ctlinput.nm_cmd;
	struct sockaddr *sa = msg->ctlinput.nm_arg;
	void *d = msg->ctlinput.nm_extra;
	struct tcphdr th;
	inp_notify_t notify = tcp_notify;
	struct ip6_hdr *ip6;
	struct mbuf *m;
	struct ip6ctlparam *ip6cp = NULL;
	const struct sockaddr_in6 *sa6_src = NULL;
	int off;
	struct tcp_portonly {
		u_int16_t th_sport;
		u_int16_t th_dport;
	} *thp;
	int arg;

	if (sa->sa_family != AF_INET6 ||
	    sa->sa_len != sizeof(struct sockaddr_in6)) {
		goto out;
	}

	arg = 0;
	if (cmd == PRC_QUENCH)
		notify = tcp_quench;
	else if (cmd == PRC_MSGSIZE) {
		/*
		 * The MTU can be passed via an icmp6 packet or directly
		 * via ip6c_cmdarg.
		 */
		struct ip6ctlparam *ip6cp = d;

		if (ip6cp->ip6c_icmp6) {
			struct icmp6_hdr *icmp6 = ip6cp->ip6c_icmp6;
			arg = ntohl(icmp6->icmp6_mtu);
		} else if (ip6cp->ip6c_cmdarg) {
			arg = *(uint32_t *)ip6cp->ip6c_cmdarg;
		} else {
			goto out;
		}
		notify = tcp_mtudisc;
	} else if (!PRC_IS_REDIRECT(cmd) &&
		 ((unsigned)cmd > PRC_NCMDS || inet6ctlerrmap[cmd] == 0)) {
		goto out;
	}

	/*
	 * If the parameter is from icmp6, decode it.  Note that in the
	 * mtu shortcut case, the rest of the ip6ctlparam content is
	 * 0 or NULL.
	 */
	if (d != NULL) {
		ip6cp = (struct ip6ctlparam *)d;
		m = ip6cp->ip6c_m;
		ip6 = ip6cp->ip6c_ip6;
		off = ip6cp->ip6c_off;
		sa6_src = ip6cp->ip6c_src;
	} else {
		m = NULL;
		ip6 = NULL;
		off = 0;	/* fool gcc */
		sa6_src = &sa6_any;
	}

	if (ip6 != NULL) {
		struct in_conninfo inc;
		/*
		 * XXX: We assume that when IPV6 is non NULL,
		 * M and OFF are valid.
		 */

		/* check if we can safely examine src and dst ports */
		if (m->m_pkthdr.len < off + sizeof *thp)
			goto out;

		bzero(&th, sizeof th);
		m_copydata(m, off, sizeof *thp, &th);

		in6_pcbnotify(&tcbinfo[0], sa, th.th_dport,
		    (struct sockaddr *)ip6cp->ip6c_src,
		    th.th_sport, cmd, arg, notify);

		inc.inc_fport = th.th_dport;
		inc.inc_lport = th.th_sport;
		inc.inc6_faddr = ((struct sockaddr_in6 *)sa)->sin6_addr;
		inc.inc6_laddr = ip6cp->ip6c_src->sin6_addr;
		inc.inc_isipv6 = 1;
		syncache_unreach(&inc, &th);
	} else {
		in6_pcbnotify(&tcbinfo[0], sa, 0,
		    (const struct sockaddr *)sa6_src, 0, cmd, arg, notify);
	}
out:
	lwkt_replymsg(&msg->ctlinput.base.lmsg, 0);
}

#endif

/*
 * Following is where TCP initial sequence number generation occurs.
 *
 * There are two places where we must use initial sequence numbers:
 * 1.  In SYN-ACK packets.
 * 2.  In SYN packets.
 *
 * All ISNs for SYN-ACK packets are generated by the syncache.  See
 * tcp_syncache.c for details.
 *
 * The ISNs in SYN packets must be monotonic; TIME_WAIT recycling
 * depends on this property.  In addition, these ISNs should be
 * unguessable so as to prevent connection hijacking.  To satisfy
 * the requirements of this situation, the algorithm outlined in
 * RFC 1948 is used to generate sequence numbers.
 *
 * Implementation details:
 *
 * net.inet.tcp.isn_reseed_interval controls the number of seconds
 * between the seeding of isn_secret.  On every reseed we jump the
 * ISN by a lot.
 */
struct tcp_isn {
	u_char	secret[16];
	MD5_CTX ctx;
	int	last_reseed;
	int	last_offset;
} __cachealign;

struct tcp_isn tcp_isn_ary[MAXCPU];

tcp_seq
tcp_new_isn(struct tcpcb *tp)
{
	struct tcp_isn *isn;
	tcp_seq new_isn;
	tcp_seq digest[16 / sizeof(tcp_seq)];
	int n;

	isn = &tcp_isn_ary[mycpuid];

	/*
	 * Reseed every 20 seconds.  6 reseeds per 2-minute interval in
	 * order to retain our monotonic offset.
	 *
	 * The initial seed randomizes last_offset with all 32 bits.
	 *
	 * Note that the md5 digest is masked with 0x0FFFFFFF, so we must
	 * add 1/16 of our full range (1/8 of our signed range) to ensure
	 * monotonic operation.
	 */
	if (isn->last_reseed == 0 ||
	    (u_int)(ticks - isn->last_reseed) > tcp_isn_reseed_interval * hz) {
		if (isn->last_reseed == 0) {
			read_random(&isn->last_offset,
				    sizeof(isn->last_offset), 1);
		}
		read_random(&isn->secret, sizeof(isn->secret), 1);
		isn->last_reseed = ticks;
		isn->last_offset += 0x10000000;
	}

	/*
	 * Compute the md5 hash, giving us a deterministic result for the
	 * port/address pair for any given secret.
	 */
	MD5Init(&isn->ctx);
	MD5Update(&isn->ctx, isn->secret, sizeof(isn->secret));
	MD5Update(&isn->ctx, (u_char *)&tp->t_inpcb->inp_fport, 2);
	MD5Update(&isn->ctx, (u_char *)&tp->t_inpcb->inp_lport, 2);
#ifdef INET6
	if (INP_ISIPV6(tp->t_inpcb)) {
		MD5Update(&isn->ctx, (u_char *)&tp->t_inpcb->in6p_faddr,
			  sizeof(struct in6_addr));
		MD5Update(&isn->ctx, (u_char *)&tp->t_inpcb->in6p_laddr,
			  sizeof(struct in6_addr));
	} else
#endif
	{
		MD5Update(&isn->ctx, (u_char *)&tp->t_inpcb->inp_faddr,
			  sizeof(struct in_addr));
		MD5Update(&isn->ctx, (u_char *)&tp->t_inpcb->inp_laddr,
			  sizeof(struct in_addr));
	}
	MD5Final((char *)digest, &isn->ctx);

	/*
	 * Add a random component 0-1048575 plus advance by 1048576.
	 *
	 * The sequence space is simply too small, in modern times we also
	 * must depend on the receive-side being a bit smarter when recycling
	 * ports in TIME_WAIT.
	 */
	read_random(&n, sizeof(n), 1);
	isn->last_offset += (n & 0x000FFFFF) + 0x00100000;
	new_isn = (digest[0] & 0x0FFFFFFF) + isn->last_offset;

	return (new_isn);
}

/*
 * When a source quench is received, close congestion window
 * to one segment.  We will gradually open it again as we proceed.
 */
void
tcp_quench(struct inpcb *inp, int error)
{
	struct tcpcb *tp = intotcpcb(inp);

	KASSERT(tp != NULL, ("tcp_quench: tp is NULL"));
	tp->snd_cwnd = tp->t_maxseg;
	tp->snd_wacked = 0;
}

/*
 * When a specific ICMP unreachable message is received and the
 * connection state is SYN-SENT, drop the connection.  This behavior
 * is controlled by the icmp_may_rst sysctl.
 */
void
tcp_drop_syn_sent(struct inpcb *inp, int error)
{
	struct tcpcb *tp = intotcpcb(inp);

	KASSERT(tp != NULL, ("tcp_drop_syn_sent: tp is NULL"));
	if (tp->t_state == TCPS_SYN_SENT)
		tcp_drop(tp, error);
}

/*
 * When a `need fragmentation' ICMP is received, update our idea of the MSS
 * based on the new value in the route.  Also nudge TCP to send something,
 * since we know the packet we just sent was dropped.
 * This duplicates some code in the tcp_mss() function in tcp_input.c.
 */
void
tcp_mtudisc(struct inpcb *inp, int mtu)
{
	struct tcpcb *tp = intotcpcb(inp);
	struct rtentry *rt;
	struct socket *so = inp->inp_socket;
	int maxopd, mss;
#ifdef INET6
	boolean_t isipv6 = INP_ISIPV6(inp);
#else
	const boolean_t isipv6 = FALSE;
#endif

	KASSERT(tp != NULL, ("tcp_mtudisc: tp is NULL"));

	/*
	 * If no MTU is provided in the ICMP message, use the
	 * next lower likely value, as specified in RFC 1191.
	 */
	if (mtu == 0) {
		int oldmtu;

		oldmtu = tp->t_maxopd + 
		    (isipv6 ?
		     sizeof(struct ip6_hdr) + sizeof(struct tcphdr) :
		     sizeof(struct tcpiphdr));
		mtu = ip_next_mtu(oldmtu, 0);
	}

	if (isipv6)
		rt = tcp_rtlookup6(&inp->inp_inc);
	else
		rt = tcp_rtlookup(&inp->inp_inc);
	if (rt != NULL) {
		if (rt->rt_rmx.rmx_mtu != 0 && rt->rt_rmx.rmx_mtu < mtu)
			mtu = rt->rt_rmx.rmx_mtu;

		maxopd = mtu -
		    (isipv6 ?
		     sizeof(struct ip6_hdr) + sizeof(struct tcphdr) :
		     sizeof(struct tcpiphdr));

		/*
		 * XXX - The following conditional probably violates the TCP
		 * spec.  The problem is that, since we don't know the
		 * other end's MSS, we are supposed to use a conservative
		 * default.  But, if we do that, then MTU discovery will
		 * never actually take place, because the conservative
		 * default is much less than the MTUs typically seen
		 * on the Internet today.  For the moment, we'll sweep
		 * this under the carpet.
		 *
		 * The conservative default might not actually be a problem
		 * if the only case this occurs is when sending an initial
		 * SYN with options and data to a host we've never talked
		 * to before.  Then, they will reply with an MSS value which
		 * will get recorded and the new parameters should get
		 * recomputed.  For Further Study.
		 */
		if (rt->rt_rmx.rmx_mssopt  && rt->rt_rmx.rmx_mssopt < maxopd)
			maxopd = rt->rt_rmx.rmx_mssopt;
	} else
		maxopd = mtu -
		    (isipv6 ?
		     sizeof(struct ip6_hdr) + sizeof(struct tcphdr) :
		     sizeof(struct tcpiphdr));

	if (tp->t_maxopd <= maxopd)
		return;
	tp->t_maxopd = maxopd;

	mss = maxopd;
	if ((tp->t_flags & (TF_REQ_TSTMP | TF_RCVD_TSTMP | TF_NOOPT)) ==
			   (TF_REQ_TSTMP | TF_RCVD_TSTMP))
		mss -= TCPOLEN_TSTAMP_APPA;

	/* round down to multiple of MCLBYTES */
#if	(MCLBYTES & (MCLBYTES - 1)) == 0    /* test if MCLBYTES power of 2 */
	if (mss > MCLBYTES)
		mss &= ~(MCLBYTES - 1);	
#else
	if (mss > MCLBYTES)
		mss = rounddown(mss, MCLBYTES);
#endif

	if (so->so_snd.ssb_hiwat < mss)
		mss = so->so_snd.ssb_hiwat;

	tp->t_maxseg = mss;
	tp->t_rtttime = 0;
	tp->snd_nxt = tp->snd_una;
	tcp_output(tp);
	tcpstat.tcps_mturesent++;
}

/*
 * Look-up the routing entry to the peer of this inpcb.  If no route
 * is found and it cannot be allocated the return NULL.  This routine
 * is called by TCP routines that access the rmx structure and by tcp_mss
 * to get the interface MTU.
 */
struct rtentry *
tcp_rtlookup(struct in_conninfo *inc)
{
	struct route *ro = &inc->inc_route;

	if (ro->ro_rt == NULL || !(ro->ro_rt->rt_flags & RTF_UP)) {
		/* No route yet, so try to acquire one */
		if (inc->inc_faddr.s_addr != INADDR_ANY) {
			/*
			 * unused portions of the structure MUST be zero'd
			 * out because rtalloc() treats it as opaque data
			 */
			bzero(&ro->ro_dst, sizeof(struct sockaddr_in));
			ro->ro_dst.sa_family = AF_INET;
			ro->ro_dst.sa_len = sizeof(struct sockaddr_in);
			((struct sockaddr_in *) &ro->ro_dst)->sin_addr =
			    inc->inc_faddr;
			rtalloc(ro);
		}
	}
	return (ro->ro_rt);
}

#ifdef INET6
struct rtentry *
tcp_rtlookup6(struct in_conninfo *inc)
{
	struct route_in6 *ro6 = &inc->inc6_route;

	if (ro6->ro_rt == NULL || !(ro6->ro_rt->rt_flags & RTF_UP)) {
		/* No route yet, so try to acquire one */
		if (!IN6_IS_ADDR_UNSPECIFIED(&inc->inc6_faddr)) {
			/*
			 * unused portions of the structure MUST be zero'd
			 * out because rtalloc() treats it as opaque data
			 */
			bzero(&ro6->ro_dst, sizeof(struct sockaddr_in6));
			ro6->ro_dst.sin6_family = AF_INET6;
			ro6->ro_dst.sin6_len = sizeof(struct sockaddr_in6);
			ro6->ro_dst.sin6_addr = inc->inc6_faddr;
			rtalloc((struct route *)ro6);
		}
	}
	return (ro6->ro_rt);
}
#endif

/*
 * TCP BANDWIDTH DELAY PRODUCT WINDOW LIMITING
 *
 * This code attempts to calculate the bandwidth-delay product as a
 * means of determining the optimal window size to maximize bandwidth,
 * minimize RTT, and avoid the over-allocation of buffers on interfaces and
 * routers.  This code also does a fairly good job keeping RTTs in check
 * across slow links like modems.  We implement an algorithm which is very
 * similar (but not meant to be) TCP/Vegas.  The code operates on the
 * transmitter side of a TCP connection and so only effects the transmit
 * side of the connection.
 *
 * BACKGROUND:  TCP makes no provision for the management of buffer space
 * at the end points or at the intermediate routers and switches.  A TCP
 * stream, whether using NewReno or not, will eventually buffer as
 * many packets as it is able and the only reason this typically works is
 * due to the fairly small default buffers made available for a connection
 * (typicaly 16K or 32K).  As machines use larger windows and/or window
 * scaling it is now fairly easy for even a single TCP connection to blow-out
 * all available buffer space not only on the local interface, but on
 * intermediate routers and switches as well.  NewReno makes a misguided
 * attempt to 'solve' this problem by waiting for an actual failure to occur,
 * then backing off, then steadily increasing the window again until another
 * failure occurs, ad-infinitum.  This results in terrible oscillation that
 * is only made worse as network loads increase and the idea of intentionally
 * blowing out network buffers is, frankly, a terrible way to manage network
 * resources.
 *
 * It is far better to limit the transmit window prior to the failure
 * condition being achieved.  There are two general ways to do this:  First
 * you can 'scan' through different transmit window sizes and locate the
 * point where the RTT stops increasing, indicating that you have filled the
 * pipe, then scan backwards until you note that RTT stops decreasing, then
 * repeat ad-infinitum.  This method works in principle but has severe
 * implementation issues due to RTT variances, timer granularity, and
 * instability in the algorithm which can lead to many false positives and
 * create oscillations as well as interact badly with other TCP streams
 * implementing the same algorithm.
 *
 * The second method is to limit the window to the bandwidth delay product
 * of the link.  This is the method we implement.  RTT variances and our
 * own manipulation of the congestion window, bwnd, can potentially
 * destabilize the algorithm.  For this reason we have to stabilize the
 * elements used to calculate the window.  We do this by using the minimum
 * observed RTT, the long term average of the observed bandwidth, and
 * by adding two segments worth of slop.  It isn't perfect but it is able
 * to react to changing conditions and gives us a very stable basis on
 * which to extend the algorithm.
 */
void
tcp_xmit_bandwidth_limit(struct tcpcb *tp, tcp_seq ack_seq)
{
	u_long bw;
	u_long ibw;
	u_long bwnd;
	int save_ticks;
	int delta_ticks;

	/*
	 * If inflight_enable is disabled in the middle of a tcp connection,
	 * make sure snd_bwnd is effectively disabled.
	 */
	if (!tcp_inflight_enable) {
		tp->snd_bwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT;
		tp->snd_bandwidth = 0;
		return;
	}

	/*
	 * Validate the delta time.  If a connection is new or has been idle
	 * a long time we have to reset the bandwidth calculator.
	 */
	save_ticks = ticks;
	cpu_ccfence();
	delta_ticks = save_ticks - tp->t_bw_rtttime;
	if (tp->t_bw_rtttime == 0 || delta_ticks < 0 || delta_ticks > hz * 10) {
		tp->t_bw_rtttime = save_ticks;
		tp->t_bw_rtseq = ack_seq;
		if (tp->snd_bandwidth == 0)
			tp->snd_bandwidth = tcp_inflight_start;
		return;
	}

	/*
	 * A delta of at least 1 tick is required.  Waiting 2 ticks will
	 * result in better (bw) accuracy.  More than that and the ramp-up
	 * will be too slow.
	 */
	if (delta_ticks == 0 || delta_ticks == 1)
		return;

	/*
	 * Sanity check, plus ignore pure window update acks.
	 */
	if ((int)(ack_seq - tp->t_bw_rtseq) <= 0)
		return;

	/*
	 * Figure out the bandwidth.  Due to the tick granularity this
	 * is a very rough number and it MUST be averaged over a fairly
	 * long period of time.  XXX we need to take into account a link
	 * that is not using all available bandwidth, but for now our
	 * slop will ramp us up if this case occurs and the bandwidth later
	 * increases.
	 */
	ibw = (int64_t)(ack_seq - tp->t_bw_rtseq) * hz / delta_ticks;
	tp->t_bw_rtttime = save_ticks;
	tp->t_bw_rtseq = ack_seq;
	bw = ((int64_t)tp->snd_bandwidth * 15 + ibw) >> 4;

	tp->snd_bandwidth = bw;

	/*
	 * Calculate the semi-static bandwidth delay product, plus two maximal
	 * segments.  The additional slop puts us squarely in the sweet
	 * spot and also handles the bandwidth run-up case.  Without the
	 * slop we could be locking ourselves into a lower bandwidth.
	 *
	 * At very high speeds the bw calculation can become overly sensitive
	 * and error prone when delta_ticks is low (e.g. usually 1).  To deal
	 * with the problem the stab must be scaled to the bw.  A stab of 50
	 * (the default) increases the bw for the purposes of the bwnd
	 * calculation by 5%.
	 *
	 * Situations Handled:
	 *	(1) Prevents over-queueing of packets on LANs, especially on
	 *	    high speed LANs, allowing larger TCP buffers to be
	 *	    specified, and also does a good job preventing
	 *	    over-queueing of packets over choke points like modems
	 *	    (at least for the transmit side).
	 *
	 *	(2) Is able to handle changing network loads (bandwidth
	 *	    drops so bwnd drops, bandwidth increases so bwnd
	 *	    increases).
	 *
	 *	(3) Theoretically should stabilize in the face of multiple
	 *	    connections implementing the same algorithm (this may need
	 *	    a little work).
	 *
	 *	(4) Stability value (defaults to 20 = 2 maximal packets) can
	 *	    be adjusted with a sysctl but typically only needs to be on
	 *	    very slow connections.  A value no smaller then 5 should
	 *	    be used, but only reduce this default if you have no other
	 *	    choice.
	 */

#define	USERTT	((tp->t_srtt + tp->t_rttvar) + tcp_inflight_adjrtt)
	bw += bw * tcp_inflight_stab / 1000;
	bwnd = (int64_t)bw * USERTT / (hz << TCP_RTT_SHIFT) +
	       (int)tp->t_maxseg * 2;
#undef USERTT

	if (tcp_inflight_debug > 0) {
		static int ltime;
		if ((u_int)(save_ticks - ltime) >= hz / tcp_inflight_debug) {
			ltime = save_ticks;
			kprintf("%p ibw %ld bw %ld rttvar %d srtt %d "
				"bwnd %ld delta %d snd_win %ld\n",
				tp, ibw, bw, tp->t_rttvar, tp->t_srtt,
				bwnd, delta_ticks, tp->snd_wnd);
		}
	}
	if ((long)bwnd < tcp_inflight_min)
		bwnd = tcp_inflight_min;
	if (bwnd > tcp_inflight_max)
		bwnd = tcp_inflight_max;
	if ((long)bwnd < tp->t_maxseg * 2)
		bwnd = tp->t_maxseg * 2;
	tp->snd_bwnd = bwnd;
}

static void
tcp_rmx_iwsegs(struct tcpcb *tp, u_long *maxsegs, u_long *capsegs)
{
	struct rtentry *rt;
	struct inpcb *inp = tp->t_inpcb;
#ifdef INET6
	boolean_t isipv6 = INP_ISIPV6(inp);
#else
	const boolean_t isipv6 = FALSE;
#endif

	/* XXX */
	if (tcp_iw_maxsegs < TCP_IW_MAXSEGS_DFLT)
		tcp_iw_maxsegs = TCP_IW_MAXSEGS_DFLT;
	if (tcp_iw_capsegs < TCP_IW_CAPSEGS_DFLT)
		tcp_iw_capsegs = TCP_IW_CAPSEGS_DFLT;

	if (isipv6)
		rt = tcp_rtlookup6(&inp->inp_inc);
	else
		rt = tcp_rtlookup(&inp->inp_inc);
	if (rt == NULL ||
	    rt->rt_rmx.rmx_iwmaxsegs < TCP_IW_MAXSEGS_DFLT ||
	    rt->rt_rmx.rmx_iwcapsegs < TCP_IW_CAPSEGS_DFLT) {
		*maxsegs = tcp_iw_maxsegs;
		*capsegs = tcp_iw_capsegs;
		return;
	}
	*maxsegs = rt->rt_rmx.rmx_iwmaxsegs;
	*capsegs = rt->rt_rmx.rmx_iwcapsegs;
}

u_long
tcp_initial_window(struct tcpcb *tp)
{
	if (tcp_do_rfc3390) {
		/*
		 * RFC3390:
		 * "If the SYN or SYN/ACK is lost, the initial window
		 *  used by a sender after a correctly transmitted SYN
		 *  MUST be one segment consisting of MSS bytes."
		 *
		 * However, we do something a little bit more aggressive
		 * then RFC3390 here:
		 * - Only if time spent in the SYN or SYN|ACK retransmition
		 *   >= 3 seconds, the IW is reduced.  We do this mainly
		 *   because when RFC3390 is published, the initial RTO is
		 *   still 3 seconds (the threshold we test here), while
		 *   after RFC6298, the initial RTO is 1 second.  This
		 *   behaviour probably still falls within the spirit of
		 *   RFC3390.
		 * - When IW is reduced, 2*MSS is used instead of 1*MSS.
		 *   Mainly to avoid sender and receiver deadlock until
		 *   delayed ACK timer expires.  And even RFC2581 does not
		 *   try to reduce IW upon SYN or SYN|ACK retransmition
		 *   timeout.
		 *
		 * See also:
		 * http://tools.ietf.org/html/draft-ietf-tcpm-initcwnd-03
		 */
		if (tp->t_rxtsyn >= TCPTV_RTOBASE3) {
			return (2 * tp->t_maxseg);
		} else {
			u_long maxsegs, capsegs;

			tcp_rmx_iwsegs(tp, &maxsegs, &capsegs);
			return min(maxsegs * tp->t_maxseg,
				   max(2 * tp->t_maxseg, capsegs * 1460));
		}
	} else {
		/*
		 * Even RFC2581 (back to 1999) allows 2*SMSS IW.
		 *
		 * Mainly to avoid sender and receiver deadlock
		 * until delayed ACK timer expires.
		 */
		return (2 * tp->t_maxseg);
	}
}

#ifdef TCP_SIGNATURE
/*
 * Compute TCP-MD5 hash of a TCP segment. (RFC2385)
 *
 * We do this over ip, tcphdr, segment data, and the key in the SADB.
 * When called from tcp_input(), we can be sure that th_sum has been
 * zeroed out and verified already.
 *
 * Return 0 if successful, otherwise return -1.
 *
 * XXX The key is retrieved from the system's PF_KEY SADB, by keying a
 * search with the destination IP address, and a 'magic SPI' to be
 * determined by the application. This is hardcoded elsewhere to 1179
 * right now. Another branch of this code exists which uses the SPD to
 * specify per-application flows but it is unstable.
 */
int
tcpsignature_compute(
	struct mbuf *m,		/* mbuf chain */
	int len,		/* length of TCP data */
	int optlen,		/* length of TCP options */
	u_char *buf,		/* storage for MD5 digest */
	u_int direction)	/* direction of flow */
{
	struct ippseudo ippseudo;
	MD5_CTX ctx;
	int doff;
	struct ip *ip;
	struct ipovly *ipovly;
	struct secasvar *sav;
	struct tcphdr *th;
#ifdef INET6
	struct ip6_hdr *ip6;
	struct in6_addr in6;
	uint32_t plen;
	uint16_t nhdr;
#endif /* INET6 */
	u_short savecsum;

	KASSERT(m != NULL, ("passed NULL mbuf. Game over."));
	KASSERT(buf != NULL, ("passed NULL storage pointer for MD5 signature"));
	/*
	 * Extract the destination from the IP header in the mbuf.
	 */
	ip = mtod(m, struct ip *);
#ifdef INET6
	ip6 = NULL;     /* Make the compiler happy. */
#endif /* INET6 */
	/*
	 * Look up an SADB entry which matches the address found in
	 * the segment.
	 */
	switch (IP_VHL_V(ip->ip_vhl)) {
	case IPVERSION:
		sav = key_allocsa(AF_INET, (caddr_t)&ip->ip_src, (caddr_t)&ip->ip_dst,
				IPPROTO_TCP, htonl(TCP_SIG_SPI));
		break;
#ifdef INET6
	case (IPV6_VERSION >> 4):
		ip6 = mtod(m, struct ip6_hdr *);
		sav = key_allocsa(AF_INET6, (caddr_t)&ip6->ip6_src, (caddr_t)&ip6->ip6_dst,
				IPPROTO_TCP, htonl(TCP_SIG_SPI));
		break;
#endif /* INET6 */
	default:
		return (EINVAL);
		/* NOTREACHED */
		break;
	}
	if (sav == NULL) {
		kprintf("%s: SADB lookup failed\n", __func__);
		return (EINVAL);
	}
	MD5Init(&ctx);

	/*
	 * Step 1: Update MD5 hash with IP pseudo-header.
	 *
	 * XXX The ippseudo header MUST be digested in network byte order,
	 * or else we'll fail the regression test. Assume all fields we've
	 * been doing arithmetic on have been in host byte order.
	 * XXX One cannot depend on ipovly->ih_len here. When called from
	 * tcp_output(), the underlying ip_len member has not yet been set.
	 */
	switch (IP_VHL_V(ip->ip_vhl)) {
	case IPVERSION:
		ipovly = (struct ipovly *)ip;
		ippseudo.ippseudo_src = ipovly->ih_src;
		ippseudo.ippseudo_dst = ipovly->ih_dst;
		ippseudo.ippseudo_pad = 0;
		ippseudo.ippseudo_p = IPPROTO_TCP;
		ippseudo.ippseudo_len = htons(len + sizeof(struct tcphdr) + optlen);
		MD5Update(&ctx, (char *)&ippseudo, sizeof(struct ippseudo));
		th = (struct tcphdr *)((u_char *)ip + sizeof(struct ip));
		doff = sizeof(struct ip) + sizeof(struct tcphdr) + optlen;
		break;
#ifdef INET6
	/*
	 * RFC 2385, 2.0  Proposal
	 * For IPv6, the pseudo-header is as described in RFC 2460, namely the
	 * 128-bit source IPv6 address, 128-bit destination IPv6 address, zero-
	 * extended next header value (to form 32 bits), and 32-bit segment
	 * length.
	 * Note: Upper-Layer Packet Length comes before Next Header.
	 */
	case (IPV6_VERSION >> 4):
		in6 = ip6->ip6_src;
		in6_clearscope(&in6);
		MD5Update(&ctx, (char *)&in6, sizeof(struct in6_addr));
		in6 = ip6->ip6_dst;
		in6_clearscope(&in6);
		MD5Update(&ctx, (char *)&in6, sizeof(struct in6_addr));
		plen = htonl(len + sizeof(struct tcphdr) + optlen);
		MD5Update(&ctx, (char *)&plen, sizeof(uint32_t));
		nhdr = 0;
		MD5Update(&ctx, (char *)&nhdr, sizeof(uint8_t));
		MD5Update(&ctx, (char *)&nhdr, sizeof(uint8_t));
		MD5Update(&ctx, (char *)&nhdr, sizeof(uint8_t));
		nhdr = IPPROTO_TCP;
		MD5Update(&ctx, (char *)&nhdr, sizeof(uint8_t));
		th = (struct tcphdr *)((u_char *)ip6 + sizeof(struct ip6_hdr));
		doff = sizeof(struct ip6_hdr) + sizeof(struct tcphdr) + optlen;
		break;
#endif /* INET6 */
	default:
		return (EINVAL);
		/* NOTREACHED */
		break;
	}
	/*
	 * Step 2: Update MD5 hash with TCP header, excluding options.
	 * The TCP checksum must be set to zero.
	 */
	savecsum = th->th_sum;
	th->th_sum = 0;
	MD5Update(&ctx, (char *)th, sizeof(struct tcphdr));
	th->th_sum = savecsum;
	/*
	 * Step 3: Update MD5 hash with TCP segment data.
	 *         Use m_apply() to avoid an early m_pullup().
	 */
	if (len > 0)
		m_apply(m, doff, len, tcpsignature_apply, &ctx);
	/*
	 * Step 4: Update MD5 hash with shared secret.
	 */
	MD5Update(&ctx, _KEYBUF(sav->key_auth), _KEYLEN(sav->key_auth));
	MD5Final(buf, &ctx);
	key_sa_recordxfer(sav, m);
	key_freesav(sav);
	return (0);
}

int
tcpsignature_apply(void *fstate, void *data, unsigned int len)
{

	MD5Update((MD5_CTX *)fstate, (unsigned char *)data, len);
	return (0);
}
#endif /* TCP_SIGNATURE */

static void
tcp_drop_sysctl_dispatch(netmsg_t nmsg)
{
	struct lwkt_msg *lmsg = &nmsg->lmsg;
	/* addrs[0] is a foreign socket, addrs[1] is a local one. */
	struct sockaddr_storage *addrs = lmsg->u.ms_resultp;
	int error;
	struct sockaddr_in *fin, *lin;
#ifdef INET6
	struct sockaddr_in6 *fin6, *lin6;
	struct in6_addr f6, l6;
#endif
	struct inpcb *inp;

	switch (addrs[0].ss_family) {
#ifdef INET6
	case AF_INET6:
		fin6 = (struct sockaddr_in6 *)&addrs[0];
		lin6 = (struct sockaddr_in6 *)&addrs[1];
		error = in6_embedscope(&f6, fin6, NULL, NULL);
		if (error)
			goto done;
		error = in6_embedscope(&l6, lin6, NULL, NULL);
		if (error)
			goto done;
		inp = in6_pcblookup_hash(&tcbinfo[mycpuid], &f6,
		    fin6->sin6_port, &l6, lin6->sin6_port, FALSE, NULL);
		break;
#endif
#ifdef INET
	case AF_INET:
		fin = (struct sockaddr_in *)&addrs[0];
		lin = (struct sockaddr_in *)&addrs[1];
		inp = in_pcblookup_hash(&tcbinfo[mycpuid], fin->sin_addr,
		    fin->sin_port, lin->sin_addr, lin->sin_port, FALSE, NULL);
		break;
#endif
	default:
		/*
		 * Must not reach here, since the address family was
		 * checked in sysctl handler.
		 */
		panic("unknown address family %d", addrs[0].ss_family);
	}
	if (inp != NULL) {
		struct tcpcb *tp = intotcpcb(inp);

		KASSERT((inp->inp_flags & INP_WILDCARD) == 0,
		    ("in wildcard hash"));
		KASSERT(tp != NULL, ("tcp_drop_sysctl_dispatch: tp is NULL"));
		KASSERT((tp->t_flags & TF_LISTEN) == 0, ("listen socket"));
		tcp_drop(tp, ECONNABORTED);
		error = 0;
	} else {
		error = ESRCH;
	}
#ifdef INET6
done:
#endif
	lwkt_replymsg(lmsg, error);
}

static int
sysctl_tcp_drop(SYSCTL_HANDLER_ARGS)
{
	/* addrs[0] is a foreign socket, addrs[1] is a local one. */
	struct sockaddr_storage addrs[2];
	struct sockaddr_in *fin, *lin;
#ifdef INET6
	struct sockaddr_in6 *fin6, *lin6;
#endif
	struct netmsg_base nmsg;
	struct lwkt_msg *lmsg = &nmsg.lmsg;
	struct lwkt_port *port = NULL;
	int error;

	fin = lin = NULL;
#ifdef INET6
	fin6 = lin6 = NULL;
#endif
	error = 0;

	if (req->oldptr != NULL || req->oldlen != 0)
		return (EINVAL);
	if (req->newptr == NULL)
		return (EPERM);
	if (req->newlen < sizeof(addrs))
		return (ENOMEM);
	error = SYSCTL_IN(req, &addrs, sizeof(addrs));
	if (error)
		return (error);

	switch (addrs[0].ss_family) {
#ifdef INET6
	case AF_INET6:
		fin6 = (struct sockaddr_in6 *)&addrs[0];
		lin6 = (struct sockaddr_in6 *)&addrs[1];
		if (fin6->sin6_len != sizeof(struct sockaddr_in6) ||
		    lin6->sin6_len != sizeof(struct sockaddr_in6))
			return (EINVAL);
		if (IN6_IS_ADDR_V4MAPPED(&fin6->sin6_addr) ||
		    IN6_IS_ADDR_V4MAPPED(&lin6->sin6_addr))
			return (EADDRNOTAVAIL);
#if 0
		error = sa6_embedscope(fin6, V_ip6_use_defzone);
		if (error)
			return (error);
		error = sa6_embedscope(lin6, V_ip6_use_defzone);
		if (error)
			return (error);
#endif
		port = tcp6_addrport();
		break;
#endif
#ifdef INET
	case AF_INET:
		fin = (struct sockaddr_in *)&addrs[0];
		lin = (struct sockaddr_in *)&addrs[1];
		if (fin->sin_len != sizeof(struct sockaddr_in) ||
		    lin->sin_len != sizeof(struct sockaddr_in))
			return (EINVAL);
		port = tcp_addrport(fin->sin_addr.s_addr, fin->sin_port,
		    lin->sin_addr.s_addr, lin->sin_port);
		break;
#endif
	default:
		return (EINVAL);
	}

	netmsg_init(&nmsg, NULL, &curthread->td_msgport, 0,
	    tcp_drop_sysctl_dispatch);
	lmsg->u.ms_resultp = addrs;
	return lwkt_domsg(port, lmsg, 0);
}

SYSCTL_PROC(_net_inet_tcp, OID_AUTO, drop,
    CTLTYPE_STRUCT | CTLFLAG_WR | CTLFLAG_SKIP, NULL,
    0, sysctl_tcp_drop, "", "Drop TCP connection");

static int
sysctl_tcps_count(SYSCTL_HANDLER_ARGS)
{
	u_long state_count[TCP_NSTATES];
	int cpu;

	memset(state_count, 0, sizeof(state_count));
	for (cpu = 0; cpu < netisr_ncpus; ++cpu) {
		int i;

		for (i = 0; i < TCP_NSTATES; ++i)
			state_count[i] += tcpstate_count[cpu].tcps_count[i];
	}

	return sysctl_handle_opaque(oidp, state_count, sizeof(state_count), req);
}
SYSCTL_PROC(_net_inet_tcp, OID_AUTO, state_count,
    CTLTYPE_OPAQUE | CTLFLAG_RD, NULL, 0,
    sysctl_tcps_count, "LU", "TCP connection counts by state");

void
tcp_pcbport_create(struct tcpcb *tp)
{
	int cpu;

	KASSERT((tp->t_flags & TF_LISTEN) && tp->t_state == TCPS_LISTEN,
	    ("not a listen tcpcb"));

	KASSERT(tp->t_pcbport == NULL, ("tcpcb port cache was created"));
	tp->t_pcbport =
		kmalloc(sizeof(struct tcp_pcbport) * netisr_ncpus,
			M_PCB,
			M_WAITOK | M_CACHEALIGN);

	for (cpu = 0; cpu < netisr_ncpus; ++cpu) {
		struct inpcbport *phd;

		phd = &tp->t_pcbport[cpu].t_phd;
		LIST_INIT(&phd->phd_pcblist);
		/* Though, not used ... */
		phd->phd_port = tp->t_inpcb->inp_lport;
	}
}

void
tcp_pcbport_merge_oncpu(struct tcpcb *tp)
{
	struct inpcbport *phd;
	struct inpcb *inp;
	int cpu = mycpuid;

	KASSERT(cpu < netisr_ncpus, ("invalid cpu%d", cpu));
	phd = &tp->t_pcbport[cpu].t_phd;

	while ((inp = LIST_FIRST(&phd->phd_pcblist)) != NULL) {
		KASSERT(inp->inp_phd == phd && inp->inp_porthash == NULL,
		    ("not on tcpcb port cache"));
		LIST_REMOVE(inp, inp_portlist);
		in_pcbinsporthash_lport(inp);
		KASSERT(inp->inp_phd == tp->t_inpcb->inp_phd &&
		    inp->inp_porthash == tp->t_inpcb->inp_porthash,
		    ("tcpcb port cache merge failed"));
	}
}

void
tcp_pcbport_destroy(struct tcpcb *tp)
{
#ifdef INVARIANTS
	int cpu;

	for (cpu = 0; cpu < netisr_ncpus; ++cpu) {
		KASSERT(LIST_EMPTY(&tp->t_pcbport[cpu].t_phd.phd_pcblist),
		    ("tcpcb port cache is not empty"));
	}
#endif
	kfree(tp->t_pcbport, M_PCB);
	tp->t_pcbport = NULL;
}