File Manager

003 File Manager

Current Path: /usr/src/sys/netinet

📁 ..
📄 accf_data.c(1.95 KB)
📄 accf_dns.c(3.37 KB)
📄 accf_http.c(8.35 KB)
📁 cc
📄 dccp.h(2.48 KB)
📄 icmp6.h(26.97 KB)
📄 icmp_var.h(3.78 KB)
📄 if_ether.c(41.26 KB)
📄 if_ether.h(4.62 KB)
📄 igmp.c(98.93 KB)
📄 igmp.h(5.36 KB)
📄 igmp_var.h(8.69 KB)
📄 in.c(43.68 KB)
📄 in.h(25.81 KB)
📄 in_cksum.c(4.09 KB)
📄 in_debug.c(3.48 KB)
📄 in_fib.c(8.62 KB)
📄 in_fib.h(2.59 KB)
📄 in_fib_algo.c(18.68 KB)
📄 in_gif.c(11.76 KB)
📄 in_jail.c(10.31 KB)
📄 in_kdtrace.c(5.61 KB)
📄 in_kdtrace.h(3.31 KB)
📄 in_mcast.c(79.22 KB)
📄 in_pcb.c(90.89 KB)
📄 in_pcb.h(34.46 KB)
📄 in_pcbgroup.c(17.28 KB)
📄 in_prot.c(2.35 KB)
📄 in_proto.c(9.36 KB)
📄 in_rmx.c(4.99 KB)
📄 in_rss.c(11.27 KB)
📄 in_rss.h(2.42 KB)
📄 in_systm.h(2.57 KB)
📄 in_var.h(15.4 KB)
📄 ip.h(7.37 KB)
📄 ip6.h(8.93 KB)
📄 ip_carp.c(53.25 KB)
📄 ip_carp.h(6.79 KB)
📄 ip_divert.c(21.74 KB)
📄 ip_divert.h(2.32 KB)
📄 ip_dummynet.h(8.94 KB)
📄 ip_ecn.c(5.83 KB)
📄 ip_ecn.h(2.1 KB)
📄 ip_encap.c(10.59 KB)
📄 ip_encap.h(3.13 KB)
📄 ip_fastfwd.c(13.79 KB)
📄 ip_fw.h(34.29 KB)
📄 ip_gre.c(15.28 KB)
📄 ip_icmp.c(31.15 KB)
📄 ip_icmp.h(8.52 KB)
📄 ip_id.c(9.78 KB)
📄 ip_input.c(37.16 KB)
📄 ip_mroute.c(75.86 KB)
📄 ip_mroute.h(13.66 KB)
📄 ip_options.c(19.9 KB)
📄 ip_options.h(2.61 KB)
📄 ip_output.c(40.67 KB)
📄 ip_reass.c(22.42 KB)
📄 ip_var.h(11.48 KB)
📁 khelp
📁 libalias
📁 netdump
📄 pim.h(4.25 KB)
📄 pim_var.h(3.14 KB)
📄 raw_ip.c(28.58 KB)
📄 sctp.h(22.97 KB)
📄 sctp_asconf.c(100.05 KB)
📄 sctp_asconf.h(3.31 KB)
📄 sctp_auth.c(50.44 KB)
📄 sctp_auth.h(8.52 KB)
📄 sctp_bsd_addr.c(13.89 KB)
📄 sctp_bsd_addr.h(2.45 KB)
📄 sctp_cc_functions.c(68.75 KB)
📄 sctp_constants.h(34.12 KB)
📄 sctp_crc32.c(4.5 KB)
📄 sctp_crc32.h(2.07 KB)
📄 sctp_header.h(17.48 KB)
📄 sctp_indata.c(175.36 KB)
📄 sctp_indata.h(4.18 KB)
📄 sctp_input.c(183.57 KB)
📄 sctp_input.h(2.43 KB)
📄 sctp_kdtrace.c(7.51 KB)
📄 sctp_kdtrace.h(3.6 KB)
📄 sctp_lock_bsd.h(15.64 KB)
📄 sctp_module.c(5.16 KB)
📄 sctp_os.h(2.73 KB)
📄 sctp_os_bsd.h(15.04 KB)
📄 sctp_output.c(362.89 KB)
📄 sctp_output.h(6.38 KB)
📄 sctp_pcb.c(198.87 KB)
📄 sctp_pcb.h(19.31 KB)
📄 sctp_peeloff.c(5.74 KB)
📄 sctp_peeloff.h(2.05 KB)
📄 sctp_ss_functions.c(30.72 KB)
📄 sctp_structs.h(38.29 KB)
📄 sctp_syscalls.c(13.94 KB)
📄 sctp_sysctl.c(37.45 KB)
📄 sctp_sysctl.h(22.9 KB)
📄 sctp_timer.c(47.92 KB)
📄 sctp_timer.h(3.07 KB)
📄 sctp_uio.h(38.07 KB)
📄 sctp_usrreq.c(216.08 KB)
📄 sctp_var.h(12.21 KB)
📄 sctputil.c(212.13 KB)
📄 sctputil.h(11.69 KB)
📄 siftr.c(45.2 KB)
📄 tcp.h(18.3 KB)
📄 tcp_debug.c(5.9 KB)
📄 tcp_debug.h(2.65 KB)
📄 tcp_fastopen.c(37.98 KB)
📄 tcp_fastopen.h(3.7 KB)
📄 tcp_fsm.h(4.25 KB)
📄 tcp_hostcache.c(21.43 KB)
📄 tcp_hostcache.h(2.92 KB)
📄 tcp_hpts.c(57.55 KB)
📄 tcp_hpts.h(9.89 KB)
📄 tcp_input.c(115.95 KB)
📄 tcp_log_buf.c(76.37 KB)
📄 tcp_log_buf.h(14.88 KB)
📄 tcp_lro.c(36.38 KB)
📄 tcp_lro.h(4.43 KB)
📄 tcp_offload.c(5.48 KB)
📄 tcp_offload.h(2.09 KB)
📄 tcp_output.c(60.16 KB)
📄 tcp_pcap.c(12.67 KB)
📄 tcp_pcap.h(1.76 KB)
📄 tcp_ratelimit.c(43.8 KB)
📄 tcp_ratelimit.h(5.07 KB)
📄 tcp_reass.c(30.75 KB)
📄 tcp_sack.c(26.74 KB)
📄 tcp_seq.h(3.57 KB)
📁 tcp_stacks
📄 tcp_stats.c(8.47 KB)
📄 tcp_subr.c(92.74 KB)
📄 tcp_syncache.c(73 KB)
📄 tcp_syncache.h(5.16 KB)
📄 tcp_timer.c(31.04 KB)
📄 tcp_timer.h(9.29 KB)
📄 tcp_timewait.c(19.06 KB)
📄 tcp_usrreq.c(71.35 KB)
📄 tcp_var.h(43.48 KB)
📄 tcpip.h(2.29 KB)
📄 toecore.c(13.51 KB)
📄 toecore.h(5.13 KB)
📄 udp.h(2.49 KB)
📄 udp_usrreq.c(44.57 KB)
📄 udp_var.h(6.48 KB)
📄 udplite.h(1.91 KB)

Editing: tcp_timewait.c

/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * 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
 */

#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");

#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/mbuf.h>
#include <sys/priv.h>
#include <sys/proc.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#ifndef INVARIANTS
#include <sys/syslog.h>
#endif
#include <sys/protosw.h>
#include <sys/random.h>

#include <vm/uma.h>

#include <net/route.h>
#include <net/if.h>
#include <net/if_var.h>
#include <net/vnet.h>

#include <netinet/in.h>
#include <netinet/in_kdtrace.h>
#include <netinet/in_pcb.h>
#include <netinet/in_systm.h>
#include <netinet/in_var.h>
#include <netinet/ip.h>
#include <netinet/ip_icmp.h>
#include <netinet/ip_var.h>
#ifdef INET6
#include <netinet/ip6.h>
#include <netinet6/in6_pcb.h>
#include <netinet6/ip6_var.h>
#include <netinet6/scope6_var.h>
#include <netinet6/nd6.h>
#endif
#include <netinet/tcp.h>
#include <netinet/tcp_fsm.h>
#include <netinet/tcp_seq.h>
#include <netinet/tcp_timer.h>
#include <netinet/tcp_var.h>
#ifdef INET6
#include <netinet6/tcp6_var.h>
#endif
#include <netinet/tcpip.h>
#ifdef TCPDEBUG
#include <netinet/tcp_debug.h>
#endif
#ifdef INET6
#include <netinet6/ip6protosw.h>
#endif

#include <machine/in_cksum.h>

#include <security/mac/mac_framework.h>

VNET_DEFINE_STATIC(uma_zone_t, tcptw_zone);
#define	V_tcptw_zone		VNET(tcptw_zone)
static int	maxtcptw;

/*
 * The timed wait queue contains references to each of the TCP sessions
 * currently in the TIME_WAIT state.  The queue pointers, including the
 * queue pointers in each tcptw structure, are protected using the global
 * timewait lock, which must be held over queue iteration and modification.
 *
 * Rules on tcptw usage:
 *  - a inpcb is always freed _after_ its tcptw
 *  - a tcptw relies on its inpcb reference counting for memory stability
 *  - a tcptw is dereferenceable only while its inpcb is locked
 */
VNET_DEFINE_STATIC(TAILQ_HEAD(, tcptw), twq_2msl);
#define	V_twq_2msl		VNET(twq_2msl)

/* Global timewait lock */
VNET_DEFINE_STATIC(struct rwlock, tw_lock);
#define	V_tw_lock		VNET(tw_lock)

#define	TW_LOCK_INIT(tw, d)	rw_init_flags(&(tw), (d), 0)
#define	TW_LOCK_DESTROY(tw)	rw_destroy(&(tw))
#define	TW_RLOCK(tw)		rw_rlock(&(tw))
#define	TW_WLOCK(tw)		rw_wlock(&(tw))
#define	TW_RUNLOCK(tw)		rw_runlock(&(tw))
#define	TW_WUNLOCK(tw)		rw_wunlock(&(tw))
#define	TW_LOCK_ASSERT(tw)	rw_assert(&(tw), RA_LOCKED)
#define	TW_RLOCK_ASSERT(tw)	rw_assert(&(tw), RA_RLOCKED)
#define	TW_WLOCK_ASSERT(tw)	rw_assert(&(tw), RA_WLOCKED)
#define	TW_UNLOCK_ASSERT(tw)	rw_assert(&(tw), RA_UNLOCKED)

static void	tcp_tw_2msl_reset(struct tcptw *, int);
static void	tcp_tw_2msl_stop(struct tcptw *, int);
static int	tcp_twrespond(struct tcptw *, int);

static int
tcptw_auto_size(void)
{
	int halfrange;

/*
	 * Max out at half the ephemeral port range so that TIME_WAIT
	 * sockets don't tie up too many ephemeral ports.
	 */
	if (V_ipport_lastauto > V_ipport_firstauto)
		halfrange = (V_ipport_lastauto - V_ipport_firstauto) / 2;
	else
		halfrange = (V_ipport_firstauto - V_ipport_lastauto) / 2;
	/* Protect against goofy port ranges smaller than 32. */
	return (imin(imax(halfrange, 32), maxsockets / 5));
}

static int
sysctl_maxtcptw(SYSCTL_HANDLER_ARGS)
{
	int error, new;

if (maxtcptw == 0)
		new = tcptw_auto_size();
	else
		new = maxtcptw;
	error = sysctl_handle_int(oidp, &new, 0, req);
	if (error == 0 && req->newptr)
		if (new >= 32) {
			maxtcptw = new;
			uma_zone_set_max(V_tcptw_zone, maxtcptw);
		}
	return (error);
}

SYSCTL_PROC(_net_inet_tcp, OID_AUTO, maxtcptw,
    CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_NEEDGIANT,
    &maxtcptw, 0, sysctl_maxtcptw, "IU",
    "Maximum number of compressed TCP TIME_WAIT entries");

VNET_DEFINE_STATIC(int, nolocaltimewait) = 0;
#define	V_nolocaltimewait	VNET(nolocaltimewait)
SYSCTL_INT(_net_inet_tcp, OID_AUTO, nolocaltimewait, CTLFLAG_VNET | CTLFLAG_RW,
    &VNET_NAME(nolocaltimewait), 0,
    "Do not create compressed TCP TIME_WAIT entries for local connections");

void
tcp_tw_zone_change(void)
{

if (maxtcptw == 0)
		uma_zone_set_max(V_tcptw_zone, tcptw_auto_size());
}

void
tcp_tw_init(void)
{

V_tcptw_zone = uma_zcreate("tcptw", sizeof(struct tcptw),
	    NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0);
	TUNABLE_INT_FETCH("net.inet.tcp.maxtcptw", &maxtcptw);
	if (maxtcptw == 0)
		uma_zone_set_max(V_tcptw_zone, tcptw_auto_size());
	else
		uma_zone_set_max(V_tcptw_zone, maxtcptw);
	TAILQ_INIT(&V_twq_2msl);
	TW_LOCK_INIT(V_tw_lock, "tcptw");
}

#ifdef VIMAGE
void
tcp_tw_destroy(void)
{
	struct tcptw *tw;
	struct epoch_tracker et;

NET_EPOCH_ENTER(et);
	while ((tw = TAILQ_FIRST(&V_twq_2msl)) != NULL)
		tcp_twclose(tw, 0);
	NET_EPOCH_EXIT(et);

TW_LOCK_DESTROY(V_tw_lock);
	uma_zdestroy(V_tcptw_zone);
}
#endif

/*
 * Move a TCP connection into TIME_WAIT state.
 *    tcbinfo is locked.
 *    inp is locked, and is unlocked before returning.
 */
void
tcp_twstart(struct tcpcb *tp)
{
	struct tcptw twlocal, *tw;
	struct inpcb *inp = tp->t_inpcb;
	struct socket *so;
	uint32_t recwin;
	bool acknow, local;
#ifdef INET6
	bool isipv6 = inp->inp_inc.inc_flags & INC_ISIPV6;
#endif

NET_EPOCH_ASSERT();
	INP_WLOCK_ASSERT(inp);

/* A dropped inp should never transition to TIME_WAIT state. */
	KASSERT((inp->inp_flags & INP_DROPPED) == 0, ("tcp_twstart: "
	    "(inp->inp_flags & INP_DROPPED) != 0"));

if (V_nolocaltimewait) {
#ifdef INET6
		if (isipv6)
			local = in6_localaddr(&inp->in6p_faddr);
		else
#endif
#ifdef INET
			local = in_localip(inp->inp_faddr);
#else
			local = false;
#endif
	} else
		local = false;

/*
	 * For use only by DTrace.  We do not reference the state
	 * after this point so modifying it in place is not a problem.
	 */
	tcp_state_change(tp, TCPS_TIME_WAIT);

if (local)
		tw = &twlocal;
	else
		tw = uma_zalloc(V_tcptw_zone, M_NOWAIT);
	if (tw == NULL) {
		/*
		 * Reached limit on total number of TIMEWAIT connections
		 * allowed. Remove a connection from TIMEWAIT queue in LRU
		 * fashion to make room for this connection.
		 *
		 * XXX:  Check if it possible to always have enough room
		 * in advance based on guarantees provided by uma_zalloc().
		 */
		tw = tcp_tw_2msl_scan(1);
		if (tw == NULL) {
			tp = tcp_close(tp);
			if (tp != NULL)
				INP_WUNLOCK(inp);
			return;
		}
	}
	/*
	 * For !local case the tcptw will hold a reference on its inpcb
	 * until tcp_twclose is called.
	 */
	tw->tw_inpcb = inp;

/*
	 * Recover last window size sent.
	 */
	so = inp->inp_socket;
	recwin = lmin(lmax(sbspace(&so->so_rcv), 0),
	    (long)TCP_MAXWIN << tp->rcv_scale);
	if (recwin < (so->so_rcv.sb_hiwat / 4) &&
	    recwin < tp->t_maxseg)
		recwin = 0;
	if (SEQ_GT(tp->rcv_adv, tp->rcv_nxt) &&
	    recwin < (tp->rcv_adv - tp->rcv_nxt))
		recwin = (tp->rcv_adv - tp->rcv_nxt);
	tw->last_win = (u_short)(recwin >> tp->rcv_scale);

/*
	 * Set t_recent if timestamps are used on the connection.
	 */
	if ((tp->t_flags & (TF_REQ_TSTMP|TF_RCVD_TSTMP|TF_NOOPT)) ==
	    (TF_REQ_TSTMP|TF_RCVD_TSTMP)) {
		tw->t_recent = tp->ts_recent;
		tw->ts_offset = tp->ts_offset;
	} else {
		tw->t_recent = 0;
		tw->ts_offset = 0;
	}

tw->snd_nxt = tp->snd_nxt;
	tw->rcv_nxt = tp->rcv_nxt;
	tw->iss     = tp->iss;
	tw->irs     = tp->irs;
	tw->t_starttime = tp->t_starttime;
	tw->tw_time = 0;

/* XXX
 * If this code will
 * be used for fin-wait-2 state also, then we may need
 * a ts_recent from the last segment.
 */
	acknow = tp->t_flags & TF_ACKNOW;

/*
	 * First, discard tcpcb state, which includes stopping its timers and
	 * freeing it.  tcp_discardcb() used to also release the inpcb, but
	 * that work is now done in the caller.
	 *
	 * Note: soisdisconnected() call used to be made in tcp_discardcb(),
	 * and might not be needed here any longer.
	 */
	tcp_discardcb(tp);
	soisdisconnected(so);
	tw->tw_so_options = so->so_options;
	inp->inp_flags |= INP_TIMEWAIT;
	if (acknow)
		tcp_twrespond(tw, TH_ACK);
	if (local)
		in_pcbdrop(inp);
	else {
		in_pcbref(inp);	/* Reference from tw */
		tw->tw_cred = crhold(so->so_cred);
		inp->inp_ppcb = tw;
		TCPSTATES_INC(TCPS_TIME_WAIT);
		tcp_tw_2msl_reset(tw, 0);
	}

/*
	 * If the inpcb owns the sole reference to the socket, then we can
	 * detach and free the socket as it is not needed in time wait.
	 */
	if (inp->inp_flags & INP_SOCKREF) {
		KASSERT(so->so_state & SS_PROTOREF,
		    ("tcp_twstart: !SS_PROTOREF"));
		inp->inp_flags &= ~INP_SOCKREF;
		INP_WUNLOCK(inp);
		SOCK_LOCK(so);
		so->so_state &= ~SS_PROTOREF;
		sofree(so);
	} else
		INP_WUNLOCK(inp);
}

/*
 * Returns 1 if the TIME_WAIT state was killed and we should start over,
 * looking for a pcb in the listen state.  Returns 0 otherwise.
 * It be called with to == NULL only for pure SYN-segments.
 */
int
tcp_twcheck(struct inpcb *inp, struct tcpopt *to, struct tcphdr *th,
    struct mbuf *m, int tlen)
{
	struct tcptw *tw;
	int thflags;
	tcp_seq seq;

NET_EPOCH_ASSERT();
	INP_WLOCK_ASSERT(inp);

/*
	 * XXXRW: Time wait state for inpcb has been recycled, but inpcb is
	 * still present.  This is undesirable, but temporarily necessary
	 * until we work out how to handle inpcb's who's timewait state has
	 * been removed.
	 */
	tw = intotw(inp);
	if (tw == NULL)
		goto drop;

thflags = th->th_flags;
	KASSERT(to != NULL || (thflags & (TH_SYN | TH_ACK)) == TH_SYN,
	        ("tcp_twcheck: called without options on a non-SYN segment"));

/*
	 * NOTE: for FIN_WAIT_2 (to be added later),
	 * must validate sequence number before accepting RST
	 */

/*
	 * If the segment contains RST:
	 *	Drop the segment - see Stevens, vol. 2, p. 964 and
	 *      RFC 1337.
	 */
	if (thflags & TH_RST)
		goto drop;

#if 0
/* PAWS not needed at the moment */
	/*
	 * RFC 1323 PAWS: If we have a timestamp reply on this segment
	 * and it's less than ts_recent, drop it.
	 */
	if ((to.to_flags & TOF_TS) != 0 && tp->ts_recent &&
	    TSTMP_LT(to.to_tsval, tp->ts_recent)) {
		if ((thflags & TH_ACK) == 0)
			goto drop;
		goto ack;
	}
	/*
	 * ts_recent is never updated because we never accept new segments.
	 */
#endif

/*
	 * If a new connection request is received
	 * while in TIME_WAIT, drop the old connection
	 * and start over if the sequence numbers
	 * are above the previous ones.
	 */
	if ((thflags & TH_SYN) && SEQ_GT(th->th_seq, tw->rcv_nxt)) {
		tcp_twclose(tw, 0);
		return (1);
	}

/*
	 * Drop the segment if it does not contain an ACK.
	 */
	if ((thflags & TH_ACK) == 0)
		goto drop;

/*
	 * If timestamps were negotiated during SYN/ACK and a
	 * segment without a timestamp is received, silently drop
	 * the segment, unless the missing timestamps are tolerated.
	 * See section 3.2 of RFC 7323.
	 */
	if (((to->to_flags & TOF_TS) == 0) && (tw->t_recent != 0) &&
	    (V_tcp_tolerate_missing_ts == 0)) {
		goto drop;
	}

/*
	 * Reset the 2MSL timer if this is a duplicate FIN.
	 */
	if (thflags & TH_FIN) {
		seq = th->th_seq + tlen + (thflags & TH_SYN ? 1 : 0);
		if (seq + 1 == tw->rcv_nxt)
			tcp_tw_2msl_reset(tw, 1);
	}

/*
	 * Acknowledge the segment if it has data or is not a duplicate ACK.
	 */
	if (thflags != TH_ACK || tlen != 0 ||
	    th->th_seq != tw->rcv_nxt || th->th_ack != tw->snd_nxt) {
		TCP_PROBE5(receive, NULL, NULL, m, NULL, th);
		tcp_twrespond(tw, TH_ACK);
		goto dropnoprobe;
	}
drop:
	TCP_PROBE5(receive, NULL, NULL, m, NULL, th);
dropnoprobe:
	INP_WUNLOCK(inp);
	m_freem(m);
	return (0);
}

void
tcp_twclose(struct tcptw *tw, int reuse)
{
	struct socket *so;
	struct inpcb *inp;

/*
	 * At this point, we are in one of two situations:
	 *
	 * (1) We have no socket, just an inpcb<->twtcp pair.  We can free
	 *     all state.
	 *
	 * (2) We have a socket -- if we own a reference, release it and
	 *     notify the socket layer.
	 */
	inp = tw->tw_inpcb;
	KASSERT((inp->inp_flags & INP_TIMEWAIT), ("tcp_twclose: !timewait"));
	KASSERT(intotw(inp) == tw, ("tcp_twclose: inp_ppcb != tw"));
	NET_EPOCH_ASSERT();
	INP_WLOCK_ASSERT(inp);

tcp_tw_2msl_stop(tw, reuse);
	inp->inp_ppcb = NULL;
	in_pcbdrop(inp);

so = inp->inp_socket;
	if (so != NULL) {
		/*
		 * If there's a socket, handle two cases: first, we own a
		 * strong reference, which we will now release, or we don't
		 * in which case another reference exists (XXXRW: think
		 * about this more), and we don't need to take action.
		 */
		if (inp->inp_flags & INP_SOCKREF) {
			inp->inp_flags &= ~INP_SOCKREF;
			INP_WUNLOCK(inp);
			SOCK_LOCK(so);
			KASSERT(so->so_state & SS_PROTOREF,
			    ("tcp_twclose: INP_SOCKREF && !SS_PROTOREF"));
			so->so_state &= ~SS_PROTOREF;
			sofree(so);
		} else {
			/*
			 * If we don't own the only reference, the socket and
			 * inpcb need to be left around to be handled by
			 * tcp_usr_detach() later.
			 */
			INP_WUNLOCK(inp);
		}
	} else {
		/*
		 * The socket has been already cleaned-up for us, only free the
		 * inpcb.
		 */
		in_pcbfree(inp);
	}
	TCPSTAT_INC(tcps_closed);
}

static int
tcp_twrespond(struct tcptw *tw, int flags)
{
	struct inpcb *inp = tw->tw_inpcb;
#if defined(INET6) || defined(INET)
	struct tcphdr *th = NULL;
#endif
	struct mbuf *m;
#ifdef INET
	struct ip *ip = NULL;
#endif
	u_int hdrlen, optlen;
	int error = 0;			/* Keep compiler happy */
	struct tcpopt to;
#ifdef INET6
	struct ip6_hdr *ip6 = NULL;
	int isipv6 = inp->inp_inc.inc_flags & INC_ISIPV6;
#endif
	hdrlen = 0;                     /* Keep compiler happy */

INP_WLOCK_ASSERT(inp);

m = m_gethdr(M_NOWAIT, MT_DATA);
	if (m == NULL)
		return (ENOBUFS);
	m->m_data += max_linkhdr;

#ifdef MAC
	mac_inpcb_create_mbuf(inp, m);
#endif

#ifdef INET6
	if (isipv6) {
		hdrlen = sizeof(struct ip6_hdr) + sizeof(struct tcphdr);
		ip6 = mtod(m, struct ip6_hdr *);
		th = (struct tcphdr *)(ip6 + 1);
		tcpip_fillheaders(inp, ip6, th);
	}
#endif
#if defined(INET6) && defined(INET)
	else
#endif
#ifdef INET
	{
		hdrlen = sizeof(struct tcpiphdr);
		ip = mtod(m, struct ip *);
		th = (struct tcphdr *)(ip + 1);
		tcpip_fillheaders(inp, ip, th);
	}
#endif
	to.to_flags = 0;

/*
	 * Send a timestamp and echo-reply if both our side and our peer
	 * have sent timestamps in our SYN's and this is not a RST.
	 */
	if (tw->t_recent && flags == TH_ACK) {
		to.to_flags |= TOF_TS;
		to.to_tsval = tcp_ts_getticks() + tw->ts_offset;
		to.to_tsecr = tw->t_recent;
	}
	optlen = tcp_addoptions(&to, (u_char *)(th + 1));

m->m_len = hdrlen + optlen;
	m->m_pkthdr.len = m->m_len;

KASSERT(max_linkhdr + m->m_len <= MHLEN, ("tcptw: mbuf too small"));

th->th_seq = htonl(tw->snd_nxt);
	th->th_ack = htonl(tw->rcv_nxt);
	th->th_off = (sizeof(struct tcphdr) + optlen) >> 2;
	th->th_flags = flags;
	th->th_win = htons(tw->last_win);

m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum);
#ifdef INET6
	if (isipv6) {
		m->m_pkthdr.csum_flags = CSUM_TCP_IPV6;
		th->th_sum = in6_cksum_pseudo(ip6,
		    sizeof(struct tcphdr) + optlen, IPPROTO_TCP, 0);
		ip6->ip6_hlim = in6_selecthlim(inp, NULL);
		TCP_PROBE5(send, NULL, NULL, ip6, NULL, th);
		error = ip6_output(m, inp->in6p_outputopts, NULL,
		    (tw->tw_so_options & SO_DONTROUTE), NULL, NULL, inp);
	}
#endif
#if defined(INET6) && defined(INET)
	else
#endif
#ifdef INET
	{
		m->m_pkthdr.csum_flags = CSUM_TCP;
		th->th_sum = in_pseudo(ip->ip_src.s_addr, ip->ip_dst.s_addr,
		    htons(sizeof(struct tcphdr) + optlen + IPPROTO_TCP));
		ip->ip_len = htons(m->m_pkthdr.len);
		if (V_path_mtu_discovery)
			ip->ip_off |= htons(IP_DF);
		TCP_PROBE5(send, NULL, NULL, ip, NULL, th);
		error = ip_output(m, inp->inp_options, NULL,
		    ((tw->tw_so_options & SO_DONTROUTE) ? IP_ROUTETOIF : 0),
		    NULL, inp);
	}
#endif
	if (flags & TH_ACK)
		TCPSTAT_INC(tcps_sndacks);
	else
		TCPSTAT_INC(tcps_sndctrl);
	TCPSTAT_INC(tcps_sndtotal);
	return (error);
}

static void
tcp_tw_2msl_reset(struct tcptw *tw, int rearm)
{

NET_EPOCH_ASSERT();
	INP_WLOCK_ASSERT(tw->tw_inpcb);

TW_WLOCK(V_tw_lock);
	if (rearm)
		TAILQ_REMOVE(&V_twq_2msl, tw, tw_2msl);
	tw->tw_time = ticks + 2 * tcp_msl;
	TAILQ_INSERT_TAIL(&V_twq_2msl, tw, tw_2msl);
	TW_WUNLOCK(V_tw_lock);
}

static void
tcp_tw_2msl_stop(struct tcptw *tw, int reuse)
{
	struct ucred *cred;
	struct inpcb *inp;
	int released __unused;

NET_EPOCH_ASSERT();

TW_WLOCK(V_tw_lock);
	inp = tw->tw_inpcb;
	tw->tw_inpcb = NULL;

TAILQ_REMOVE(&V_twq_2msl, tw, tw_2msl);
	cred = tw->tw_cred;
	tw->tw_cred = NULL;
	TW_WUNLOCK(V_tw_lock);

if (cred != NULL)
		crfree(cred);

released = in_pcbrele_wlocked(inp);
	KASSERT(!released, ("%s: inp should not be released here", __func__));

if (!reuse)
		uma_zfree(V_tcptw_zone, tw);
	TCPSTATES_DEC(TCPS_TIME_WAIT);
}

struct tcptw *
tcp_tw_2msl_scan(int reuse)
{
	struct tcptw *tw;
	struct inpcb *inp;

NET_EPOCH_ASSERT();

for (;;) {
		TW_RLOCK(V_tw_lock);
		tw = TAILQ_FIRST(&V_twq_2msl);
		if (tw == NULL || (!reuse && (tw->tw_time - ticks) > 0)) {
			TW_RUNLOCK(V_tw_lock);
			break;
		}
		KASSERT(tw->tw_inpcb != NULL, ("%s: tw->tw_inpcb == NULL",
		    __func__));

inp = tw->tw_inpcb;
		in_pcbref(inp);
		TW_RUNLOCK(V_tw_lock);

INP_WLOCK(inp);
		tw = intotw(inp);
		if (in_pcbrele_wlocked(inp)) {
			if (__predict_true(tw == NULL)) {
				continue;
			} else {
				/* This should not happen as in TIMEWAIT
				 * state the inp should not be destroyed
				 * before its tcptw. If INVARIANTS is
				 * defined panic.
				 */
#ifdef INVARIANTS
				panic("%s: Panic before an infinite "
					  "loop: INP_TIMEWAIT && (INP_FREED "
					  "|| inp last reference) && tw != "
					  "NULL", __func__);
#else
				log(LOG_ERR, "%s: Avoid an infinite "
					"loop: INP_TIMEWAIT && (INP_FREED "
					"|| inp last reference) && tw != "
					"NULL", __func__);
#endif
				break;
			}
		}

if (tw == NULL) {
			/* tcp_twclose() has already been called */
			INP_WUNLOCK(inp);
			continue;
		}

tcp_twclose(tw, reuse);
		if (reuse)
			return tw;
	}

return NULL;
}

003 File Manager

Editing: tcp_timewait.c

Upload File

Create Folder