tcp_timewait.c revision 190787
1139823Simp/*- 211150Swollman * Copyright (c) 1982, 1986, 1988, 1990, 1993, 1995 31541Srgrimes * The Regents of the University of California. All rights reserved. 41541Srgrimes * 51541Srgrimes * Redistribution and use in source and binary forms, with or without 61541Srgrimes * modification, are permitted provided that the following conditions 71541Srgrimes * are met: 81541Srgrimes * 1. Redistributions of source code must retain the above copyright 91541Srgrimes * notice, this list of conditions and the following disclaimer. 101541Srgrimes * 2. Redistributions in binary form must reproduce the above copyright 111541Srgrimes * notice, this list of conditions and the following disclaimer in the 121541Srgrimes * documentation and/or other materials provided with the distribution. 131541Srgrimes * 4. Neither the name of the University nor the names of its contributors 141541Srgrimes * may be used to endorse or promote products derived from this software 151541Srgrimes * without specific prior written permission. 161541Srgrimes * 171541Srgrimes * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 181541Srgrimes * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 191541Srgrimes * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 201541Srgrimes * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 211541Srgrimes * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 221541Srgrimes * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 231541Srgrimes * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 241541Srgrimes * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 251541Srgrimes * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 261541Srgrimes * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 271541Srgrimes * SUCH DAMAGE. 281541Srgrimes * 2911150Swollman * @(#)tcp_subr.c 8.2 (Berkeley) 5/24/95 301541Srgrimes */ 311541Srgrimes 32172467Ssilby#include <sys/cdefs.h> 33172467Ssilby__FBSDID("$FreeBSD: head/sys/netinet/tcp_timewait.c 190787 2009-04-06 22:29:41Z zec $"); 34172467Ssilby 35125680Sbms#include "opt_inet.h" 3654263Sshin#include "opt_inet6.h" 37101106Srwatson#include "opt_mac.h" 3829514Sjoerg#include "opt_tcpdebug.h" 3929514Sjoerg 401541Srgrimes#include <sys/param.h> 411541Srgrimes#include <sys/systm.h> 4250673Sjlemon#include <sys/callout.h> 4312172Sphk#include <sys/kernel.h> 4412172Sphk#include <sys/sysctl.h> 451541Srgrimes#include <sys/malloc.h> 461541Srgrimes#include <sys/mbuf.h> 47164033Srwatson#include <sys/priv.h> 4848758Sgreen#include <sys/proc.h> 491541Srgrimes#include <sys/socket.h> 501541Srgrimes#include <sys/socketvar.h> 511541Srgrimes#include <sys/protosw.h> 5275619Skris#include <sys/random.h> 53181803Sbz#include <sys/vimage.h> 5434923Sbde 5592760Sjeff#include <vm/uma.h> 561541Srgrimes 571541Srgrimes#include <net/route.h> 581541Srgrimes#include <net/if.h> 591541Srgrimes 601541Srgrimes#include <netinet/in.h> 611541Srgrimes#include <netinet/in_systm.h> 621541Srgrimes#include <netinet/ip.h> 6355679Sshin#ifdef INET6 6455679Sshin#include <netinet/ip6.h> 6555679Sshin#endif 661541Srgrimes#include <netinet/in_pcb.h> 6755679Sshin#ifdef INET6 6855679Sshin#include <netinet6/in6_pcb.h> 6955679Sshin#endif 707090Sbde#include <netinet/in_var.h> 711541Srgrimes#include <netinet/ip_var.h> 7255679Sshin#ifdef INET6 7355679Sshin#include <netinet6/ip6_var.h> 74148385Sume#include <netinet6/scope6_var.h> 75122922Sandre#include <netinet6/nd6.h> 7655679Sshin#endif 77145360Sandre#include <netinet/ip_icmp.h> 781541Srgrimes#include <netinet/tcp.h> 791541Srgrimes#include <netinet/tcp_fsm.h> 801541Srgrimes#include <netinet/tcp_seq.h> 811541Srgrimes#include <netinet/tcp_timer.h> 821541Srgrimes#include <netinet/tcp_var.h> 8355679Sshin#ifdef INET6 8455679Sshin#include <netinet6/tcp6_var.h> 8555679Sshin#endif 861541Srgrimes#include <netinet/tcpip.h> 876283Swollman#ifdef TCPDEBUG 886283Swollman#include <netinet/tcp_debug.h> 896283Swollman#endif 9055679Sshin#include <netinet6/ip6protosw.h> 91185571Sbz#include <netinet/vinet.h> 921541Srgrimes 9358698Sjlemon#include <machine/in_cksum.h> 9458698Sjlemon 95163606Srwatson#include <security/mac/mac_framework.h> 96163606Srwatson 97157478Sglebiusstatic int maxtcptw; 98162767Ssilby 99169608Sandre/* 100169608Sandre * The timed wait queue contains references to each of the TCP sessions 101169608Sandre * currently in the TIME_WAIT state. The queue pointers, including the 102169608Sandre * queue pointers in each tcptw structure, are protected using the global 103169608Sandre * tcbinfo lock, which must be held over queue iteration and modification. 104169608Sandre */ 105185088Szec#ifdef VIMAGE_GLOBALS 106190787Szecstatic uma_zone_t tcptw_zone; 107169608Sandrestatic TAILQ_HEAD(, tcptw) twq_2msl; 108185088Szecint nolocaltimewait; 109185088Szec#endif 110169608Sandre 111169608Sandrestatic void tcp_tw_2msl_reset(struct tcptw *, int); 112169608Sandrestatic void tcp_tw_2msl_stop(struct tcptw *); 113169608Sandre 114162031Sglebiusstatic int 115162767Ssilbytcptw_auto_size(void) 116162767Ssilby{ 117183550Szec INIT_VNET_INET(curvnet); 118162767Ssilby int halfrange; 119162767Ssilby 120162767Ssilby /* 121162768Smaxim * Max out at half the ephemeral port range so that TIME_WAIT 122162768Smaxim * sockets don't tie up too many ephemeral ports. 123162768Smaxim */ 124181803Sbz if (V_ipport_lastauto > V_ipport_firstauto) 125181803Sbz halfrange = (V_ipport_lastauto - V_ipport_firstauto) / 2; 126162767Ssilby else 127181803Sbz halfrange = (V_ipport_firstauto - V_ipport_lastauto) / 2; 128162767Ssilby /* Protect against goofy port ranges smaller than 32. */ 129162767Ssilby return (imin(imax(halfrange, 32), maxsockets / 5)); 130162767Ssilby} 131162767Ssilby 132162767Ssilbystatic int 133162031Sglebiussysctl_maxtcptw(SYSCTL_HANDLER_ARGS) 134162031Sglebius{ 135162031Sglebius int error, new; 136157478Sglebius 137162031Sglebius if (maxtcptw == 0) 138162767Ssilby new = tcptw_auto_size(); 139162031Sglebius else 140162031Sglebius new = maxtcptw; 141170289Sdwmalone error = sysctl_handle_int(oidp, &new, 0, req); 142162767Ssilby if (error == 0 && req->newptr) 143162767Ssilby if (new >= 32) { 144162031Sglebius maxtcptw = new; 145190787Szec uma_zone_set_max(V_tcptw_zone, maxtcptw); 146162767Ssilby } 147162031Sglebius return (error); 148162031Sglebius} 149169541Sandre 150162031SglebiusSYSCTL_PROC(_net_inet_tcp, OID_AUTO, maxtcptw, CTLTYPE_INT|CTLFLAG_RW, 151162031Sglebius &maxtcptw, 0, sysctl_maxtcptw, "IU", 152162031Sglebius "Maximum number of compressed TCP TIME_WAIT entries"); 153162031Sglebius 154185348SzecSYSCTL_V_INT(V_NET, vnet_inet, _net_inet_tcp, OID_AUTO, nolocaltimewait, 155185348Szec CTLFLAG_RW, nolocaltimewait, 0, 156167721Sandre "Do not create compressed TCP TIME_WAIT entries for local connections"); 157162151Sglebius 158169541Sandrevoid 159169541Sandretcp_tw_zone_change(void) 160157927Sps{ 161157927Sps 162162031Sglebius if (maxtcptw == 0) 163190787Szec uma_zone_set_max(V_tcptw_zone, tcptw_auto_size()); 164157927Sps} 165157927Sps 1661541Srgrimesvoid 167169541Sandretcp_tw_init(void) 1681541Srgrimes{ 169183550Szec INIT_VNET_INET(curvnet); 170169454Srwatson 171190787Szec V_tcptw_zone = uma_zcreate("tcptw", sizeof(struct tcptw), 172162031Sglebius NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE); 173157478Sglebius TUNABLE_INT_FETCH("net.inet.tcp.maxtcptw", &maxtcptw); 174157478Sglebius if (maxtcptw == 0) 175190787Szec uma_zone_set_max(V_tcptw_zone, tcptw_auto_size()); 176162031Sglebius else 177190787Szec uma_zone_set_max(V_tcptw_zone, maxtcptw); 178181803Sbz TAILQ_INIT(&V_twq_2msl); 1791541Srgrimes} 1801541Srgrimes 1811541Srgrimes/* 182111145Sjlemon * Move a TCP connection into TIME_WAIT state. 183138410Srwatson * tcbinfo is locked. 184111145Sjlemon * inp is locked, and is unlocked before returning. 185111145Sjlemon */ 186111145Sjlemonvoid 187157431Srwatsontcp_twstart(struct tcpcb *tp) 188111145Sjlemon{ 189183550Szec#if defined(INVARIANTS) || defined(INVARIANT_SUPPORT) 190183550Szec INIT_VNET_INET(tp->t_vnet); 191183550Szec#endif 192111145Sjlemon struct tcptw *tw; 193162151Sglebius struct inpcb *inp = tp->t_inpcb; 194162111Sru int acknow; 195111145Sjlemon struct socket *so; 196111145Sjlemon 197181803Sbz INP_INFO_WLOCK_ASSERT(&V_tcbinfo); /* tcp_tw_2msl_reset(). */ 198178285Srwatson INP_WLOCK_ASSERT(inp); 199138020Srwatson 200181803Sbz if (V_nolocaltimewait && in_localip(inp->inp_faddr)) { 201162151Sglebius tp = tcp_close(tp); 202162151Sglebius if (tp != NULL) 203178285Srwatson INP_WUNLOCK(inp); 204162151Sglebius return; 205162151Sglebius } 206162151Sglebius 207190787Szec tw = uma_zalloc(V_tcptw_zone, M_NOWAIT); 208112009Sjlemon if (tw == NULL) { 209169608Sandre tw = tcp_tw_2msl_scan(1); 210112009Sjlemon if (tw == NULL) { 211157376Srwatson tp = tcp_close(tp); 212157376Srwatson if (tp != NULL) 213178285Srwatson INP_WUNLOCK(inp); 214112009Sjlemon return; 215112009Sjlemon } 216112009Sjlemon } 217111145Sjlemon tw->tw_inpcb = inp; 218111145Sjlemon 219111145Sjlemon /* 220111145Sjlemon * Recover last window size sent. 221111145Sjlemon */ 222111145Sjlemon tw->last_win = (tp->rcv_adv - tp->rcv_nxt) >> tp->rcv_scale; 223111145Sjlemon 224111145Sjlemon /* 225111145Sjlemon * Set t_recent if timestamps are used on the connection. 226111145Sjlemon */ 227133874Srwatson if ((tp->t_flags & (TF_REQ_TSTMP|TF_RCVD_TSTMP|TF_NOOPT)) == 228169477Sandre (TF_REQ_TSTMP|TF_RCVD_TSTMP)) { 229111145Sjlemon tw->t_recent = tp->ts_recent; 230169477Sandre tw->ts_offset = tp->ts_offset; 231169477Sandre } else { 232111145Sjlemon tw->t_recent = 0; 233169477Sandre tw->ts_offset = 0; 234169477Sandre } 235111145Sjlemon 236111145Sjlemon tw->snd_nxt = tp->snd_nxt; 237111145Sjlemon tw->rcv_nxt = tp->rcv_nxt; 238121850Ssilby tw->iss = tp->iss; 239121884Ssilby tw->irs = tp->irs; 240111145Sjlemon tw->t_starttime = tp->t_starttime; 241112009Sjlemon tw->tw_time = 0; 242111145Sjlemon 243111145Sjlemon/* XXX 244111145Sjlemon * If this code will 245111145Sjlemon * be used for fin-wait-2 state also, then we may need 246111145Sjlemon * a ts_recent from the last segment. 247111145Sjlemon */ 248137139Sandre acknow = tp->t_flags & TF_ACKNOW; 249157376Srwatson 250157376Srwatson /* 251157376Srwatson * First, discard tcpcb state, which includes stopping its timers and 252157376Srwatson * freeing it. tcp_discardcb() used to also release the inpcb, but 253157376Srwatson * that work is now done in the caller. 254160925Srwatson * 255160925Srwatson * Note: soisdisconnected() call used to be made in tcp_discardcb(), 256160925Srwatson * and might not be needed here any longer. 257157376Srwatson */ 258111145Sjlemon tcp_discardcb(tp); 259111145Sjlemon so = inp->inp_socket; 260160925Srwatson soisdisconnected(so); 261169347Srwatson tw->tw_cred = crhold(so->so_cred); 262130387Srwatson SOCK_LOCK(so); 263111145Sjlemon tw->tw_so_options = so->so_options; 264157376Srwatson SOCK_UNLOCK(so); 265114794Srwatson if (acknow) 266126351Srwatson tcp_twrespond(tw, TH_ACK); 267157432Srwatson inp->inp_ppcb = tw; 268189848Srwatson inp->inp_flags |= INP_TIMEWAIT; 269169608Sandre tcp_tw_2msl_reset(tw, 0); 270157376Srwatson 271157376Srwatson /* 272157376Srwatson * If the inpcb owns the sole reference to the socket, then we can 273157376Srwatson * detach and free the socket as it is not needed in time wait. 274157376Srwatson */ 275189848Srwatson if (inp->inp_flags & INP_SOCKREF) { 276157376Srwatson KASSERT(so->so_state & SS_PROTOREF, 277157376Srwatson ("tcp_twstart: !SS_PROTOREF")); 278189848Srwatson inp->inp_flags &= ~INP_SOCKREF; 279178285Srwatson INP_WUNLOCK(inp); 280157376Srwatson ACCEPT_LOCK(); 281157376Srwatson SOCK_LOCK(so); 282157376Srwatson so->so_state &= ~SS_PROTOREF; 283157376Srwatson sofree(so); 284157376Srwatson } else 285178285Srwatson INP_WUNLOCK(inp); 286111145Sjlemon} 287111145Sjlemon 288162064Sglebius#if 0 289121850Ssilby/* 290121884Ssilby * The appromixate rate of ISN increase of Microsoft TCP stacks; 291121884Ssilby * the actual rate is slightly higher due to the addition of 292121884Ssilby * random positive increments. 293121884Ssilby * 294121884Ssilby * Most other new OSes use semi-randomized ISN values, so we 295121884Ssilby * do not need to worry about them. 296121884Ssilby */ 297121884Ssilby#define MS_ISN_BYTES_PER_SECOND 250000 298121884Ssilby 299121884Ssilby/* 300121850Ssilby * Determine if the ISN we will generate has advanced beyond the last 301121850Ssilby * sequence number used by the previous connection. If so, indicate 302121850Ssilby * that it is safe to recycle this tw socket by returning 1. 303121850Ssilby */ 304121850Ssilbyint 305121850Ssilbytcp_twrecycleable(struct tcptw *tw) 306121850Ssilby{ 307183550Szec INIT_VNET_INET(curvnet); 308121884Ssilby tcp_seq new_iss = tw->iss; 309121884Ssilby tcp_seq new_irs = tw->irs; 310121850Ssilby 311181803Sbz INP_INFO_WLOCK_ASSERT(&V_tcbinfo); 312121884Ssilby new_iss += (ticks - tw->t_starttime) * (ISN_BYTES_PER_SECOND / hz); 313121884Ssilby new_irs += (ticks - tw->t_starttime) * (MS_ISN_BYTES_PER_SECOND / hz); 314133874Srwatson 315121884Ssilby if (SEQ_GT(new_iss, tw->snd_nxt) && SEQ_GT(new_irs, tw->rcv_nxt)) 316139222Srwatson return (1); 317121850Ssilby else 318139222Srwatson return (0); 319121850Ssilby} 320162064Sglebius#endif 321121850Ssilby 322169608Sandre/* 323169608Sandre * Returns 1 if the TIME_WAIT state was killed and we should start over, 324169608Sandre * looking for a pcb in the listen state. Returns 0 otherwise. 325169608Sandre */ 326169608Sandreint 327169608Sandretcp_twcheck(struct inpcb *inp, struct tcpopt *to, struct tcphdr *th, 328169608Sandre struct mbuf *m, int tlen) 329169608Sandre{ 330183550Szec#if defined(INVARIANTS) || defined(INVARIANT_SUPPORT) 331183550Szec INIT_VNET_INET(curvnet); 332183550Szec#endif 333169608Sandre struct tcptw *tw; 334169608Sandre int thflags; 335169608Sandre tcp_seq seq; 336169608Sandre 337169608Sandre /* tcbinfo lock required for tcp_twclose(), tcp_tw_2msl_reset(). */ 338181803Sbz INP_INFO_WLOCK_ASSERT(&V_tcbinfo); 339178285Srwatson INP_WLOCK_ASSERT(inp); 340169608Sandre 341169608Sandre /* 342169608Sandre * XXXRW: Time wait state for inpcb has been recycled, but inpcb is 343169608Sandre * still present. This is undesirable, but temporarily necessary 344169608Sandre * until we work out how to handle inpcb's who's timewait state has 345169608Sandre * been removed. 346169608Sandre */ 347169608Sandre tw = intotw(inp); 348169608Sandre if (tw == NULL) 349169608Sandre goto drop; 350169608Sandre 351169608Sandre thflags = th->th_flags; 352169608Sandre 353169608Sandre /* 354169608Sandre * NOTE: for FIN_WAIT_2 (to be added later), 355169608Sandre * must validate sequence number before accepting RST 356169608Sandre */ 357169608Sandre 358169608Sandre /* 359169608Sandre * If the segment contains RST: 360169608Sandre * Drop the segment - see Stevens, vol. 2, p. 964 and 361169608Sandre * RFC 1337. 362169608Sandre */ 363169608Sandre if (thflags & TH_RST) 364169608Sandre goto drop; 365169608Sandre 366169608Sandre#if 0 367169608Sandre/* PAWS not needed at the moment */ 368169608Sandre /* 369169608Sandre * RFC 1323 PAWS: If we have a timestamp reply on this segment 370169608Sandre * and it's less than ts_recent, drop it. 371169608Sandre */ 372169608Sandre if ((to.to_flags & TOF_TS) != 0 && tp->ts_recent && 373169608Sandre TSTMP_LT(to.to_tsval, tp->ts_recent)) { 374169608Sandre if ((thflags & TH_ACK) == 0) 375169608Sandre goto drop; 376169608Sandre goto ack; 377169608Sandre } 378169608Sandre /* 379169608Sandre * ts_recent is never updated because we never accept new segments. 380169608Sandre */ 381169608Sandre#endif 382169608Sandre 383169608Sandre /* 384169608Sandre * If a new connection request is received 385169608Sandre * while in TIME_WAIT, drop the old connection 386169608Sandre * and start over if the sequence numbers 387169608Sandre * are above the previous ones. 388169608Sandre */ 389169608Sandre if ((thflags & TH_SYN) && SEQ_GT(th->th_seq, tw->rcv_nxt)) { 390169608Sandre tcp_twclose(tw, 0); 391169608Sandre return (1); 392169608Sandre } 393169608Sandre 394169608Sandre /* 395169608Sandre * Drop the the segment if it does not contain an ACK. 396169608Sandre */ 397169608Sandre if ((thflags & TH_ACK) == 0) 398169608Sandre goto drop; 399169608Sandre 400169608Sandre /* 401169608Sandre * Reset the 2MSL timer if this is a duplicate FIN. 402169608Sandre */ 403169608Sandre if (thflags & TH_FIN) { 404169608Sandre seq = th->th_seq + tlen + (thflags & TH_SYN ? 1 : 0); 405169608Sandre if (seq + 1 == tw->rcv_nxt) 406169608Sandre tcp_tw_2msl_reset(tw, 1); 407169608Sandre } 408169608Sandre 409169608Sandre /* 410169608Sandre * Acknowledge the segment if it has data or is not a duplicate ACK. 411169608Sandre */ 412169608Sandre if (thflags != TH_ACK || tlen != 0 || 413169608Sandre th->th_seq != tw->rcv_nxt || th->th_ack != tw->snd_nxt) 414169608Sandre tcp_twrespond(tw, TH_ACK); 415169608Sandredrop: 416178285Srwatson INP_WUNLOCK(inp); 417169608Sandre m_freem(m); 418169608Sandre return (0); 419169608Sandre} 420169608Sandre 421157376Srwatsonvoid 422112009Sjlemontcp_twclose(struct tcptw *tw, int reuse) 423111145Sjlemon{ 424183550Szec INIT_VNET_INET(curvnet); 425157376Srwatson struct socket *so; 426111145Sjlemon struct inpcb *inp; 427111145Sjlemon 428157376Srwatson /* 429157386Srwatson * At this point, we are in one of two situations: 430157376Srwatson * 431160549Srwatson * (1) We have no socket, just an inpcb<->twtcp pair. We can free 432160549Srwatson * all state. 433157386Srwatson * 434160549Srwatson * (2) We have a socket -- if we own a reference, release it and 435160549Srwatson * notify the socket layer. 436157376Srwatson */ 437111145Sjlemon inp = tw->tw_inpcb; 438189848Srwatson KASSERT((inp->inp_flags & INP_TIMEWAIT), ("tcp_twclose: !timewait")); 439157432Srwatson KASSERT(intotw(inp) == tw, ("tcp_twclose: inp_ppcb != tw")); 440181803Sbz INP_INFO_WLOCK_ASSERT(&V_tcbinfo); /* tcp_tw_2msl_stop(). */ 441178285Srwatson INP_WLOCK_ASSERT(inp); 442138020Srwatson 443111145Sjlemon tw->tw_inpcb = NULL; 444169608Sandre tcp_tw_2msl_stop(tw); 445111145Sjlemon inp->inp_ppcb = NULL; 446158009Srwatson in_pcbdrop(inp); 447157376Srwatson 448157376Srwatson so = inp->inp_socket; 449157386Srwatson if (so != NULL) { 450160549Srwatson /* 451160549Srwatson * If there's a socket, handle two cases: first, we own a 452160549Srwatson * strong reference, which we will now release, or we don't 453160549Srwatson * in which case another reference exists (XXXRW: think 454160549Srwatson * about this more), and we don't need to take action. 455160549Srwatson */ 456189848Srwatson if (inp->inp_flags & INP_SOCKREF) { 457189848Srwatson inp->inp_flags &= ~INP_SOCKREF; 458178285Srwatson INP_WUNLOCK(inp); 459157386Srwatson ACCEPT_LOCK(); 460157386Srwatson SOCK_LOCK(so); 461157386Srwatson KASSERT(so->so_state & SS_PROTOREF, 462157386Srwatson ("tcp_twclose: INP_SOCKREF && !SS_PROTOREF")); 463157386Srwatson so->so_state &= ~SS_PROTOREF; 464157386Srwatson sofree(so); 465157376Srwatson } else { 466157386Srwatson /* 467157386Srwatson * If we don't own the only reference, the socket and 468157386Srwatson * inpcb need to be left around to be handled by 469157386Srwatson * tcp_usr_detach() later. 470157386Srwatson */ 471178285Srwatson INP_WUNLOCK(inp); 472157376Srwatson } 473185370Sbz } else 474185370Sbz in_pcbfree(inp); 475181803Sbz V_tcpstat.tcps_closed++; 476126002Spjd crfree(tw->tw_cred); 477126002Spjd tw->tw_cred = NULL; 478112009Sjlemon if (reuse) 479157376Srwatson return; 480190787Szec uma_zfree(V_tcptw_zone, tw); 481111145Sjlemon} 482111145Sjlemon 483111145Sjlemonint 484126351Srwatsontcp_twrespond(struct tcptw *tw, int flags) 485111145Sjlemon{ 486183550Szec INIT_VNET_INET(curvnet); 487111145Sjlemon struct inpcb *inp = tw->tw_inpcb; 488111145Sjlemon struct tcphdr *th; 489111145Sjlemon struct mbuf *m; 490111145Sjlemon struct ip *ip = NULL; 491111145Sjlemon u_int hdrlen, optlen; 492111145Sjlemon int error; 493168845Sandre struct tcpopt to; 494111145Sjlemon#ifdef INET6 495111145Sjlemon struct ip6_hdr *ip6 = NULL; 496186222Sbz int isipv6 = inp->inp_inc.inc_flags & INC_ISIPV6; 497111145Sjlemon#endif 498111145Sjlemon 499178285Srwatson INP_WLOCK_ASSERT(inp); 500138020Srwatson 501151967Sandre m = m_gethdr(M_DONTWAIT, MT_DATA); 502111145Sjlemon if (m == NULL) 503111145Sjlemon return (ENOBUFS); 504111145Sjlemon m->m_data += max_linkhdr; 505111145Sjlemon 506114794Srwatson#ifdef MAC 507172930Srwatson mac_inpcb_create_mbuf(inp, m); 508114794Srwatson#endif 509114794Srwatson 510111153Sjlemon#ifdef INET6 511111145Sjlemon if (isipv6) { 512111145Sjlemon hdrlen = sizeof(struct ip6_hdr) + sizeof(struct tcphdr); 513111145Sjlemon ip6 = mtod(m, struct ip6_hdr *); 514111145Sjlemon th = (struct tcphdr *)(ip6 + 1); 515111145Sjlemon tcpip_fillheaders(inp, ip6, th); 516111153Sjlemon } else 517111153Sjlemon#endif 518111153Sjlemon { 519111145Sjlemon hdrlen = sizeof(struct tcpiphdr); 520111145Sjlemon ip = mtod(m, struct ip *); 521111145Sjlemon th = (struct tcphdr *)(ip + 1); 522111145Sjlemon tcpip_fillheaders(inp, ip, th); 523111145Sjlemon } 524168845Sandre to.to_flags = 0; 525133874Srwatson 526133874Srwatson /* 527111145Sjlemon * Send a timestamp and echo-reply if both our side and our peer 528111145Sjlemon * have sent timestamps in our SYN's and this is not a RST. 529133874Srwatson */ 530111145Sjlemon if (tw->t_recent && flags == TH_ACK) { 531168845Sandre to.to_flags |= TOF_TS; 532169477Sandre to.to_tsval = ticks + tw->ts_offset; 533168845Sandre to.to_tsecr = tw->t_recent; 534133874Srwatson } 535168845Sandre optlen = tcp_addoptions(&to, (u_char *)(th + 1)); 536111145Sjlemon 537111145Sjlemon m->m_len = hdrlen + optlen; 538111145Sjlemon m->m_pkthdr.len = m->m_len; 539111145Sjlemon 540111145Sjlemon KASSERT(max_linkhdr + m->m_len <= MHLEN, ("tcptw: mbuf too small")); 541111145Sjlemon 542111145Sjlemon th->th_seq = htonl(tw->snd_nxt); 543111145Sjlemon th->th_ack = htonl(tw->rcv_nxt); 544111145Sjlemon th->th_off = (sizeof(struct tcphdr) + optlen) >> 2; 545111145Sjlemon th->th_flags = flags; 546111145Sjlemon th->th_win = htons(tw->last_win); 547111145Sjlemon 548111153Sjlemon#ifdef INET6 549111145Sjlemon if (isipv6) { 550111145Sjlemon th->th_sum = in6_cksum(m, IPPROTO_TCP, sizeof(struct ip6_hdr), 551111145Sjlemon sizeof(struct tcphdr) + optlen); 552122922Sandre ip6->ip6_hlim = in6_selecthlim(inp, NULL); 553122922Sandre error = ip6_output(m, inp->in6p_outputopts, NULL, 554111145Sjlemon (tw->tw_so_options & SO_DONTROUTE), NULL, NULL, inp); 555111153Sjlemon } else 556111153Sjlemon#endif 557111153Sjlemon { 558111145Sjlemon th->th_sum = in_pseudo(ip->ip_src.s_addr, ip->ip_dst.s_addr, 559133874Srwatson htons(sizeof(struct tcphdr) + optlen + IPPROTO_TCP)); 560111145Sjlemon m->m_pkthdr.csum_flags = CSUM_TCP; 561111145Sjlemon m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum); 562111145Sjlemon ip->ip_len = m->m_pkthdr.len; 563181803Sbz if (V_path_mtu_discovery) 564124248Sandre ip->ip_off |= IP_DF; 565122922Sandre error = ip_output(m, inp->inp_options, NULL, 566134793Sjmg ((tw->tw_so_options & SO_DONTROUTE) ? IP_ROUTETOIF : 0), 567134793Sjmg NULL, inp); 568111145Sjlemon } 569111145Sjlemon if (flags & TH_ACK) 570181803Sbz V_tcpstat.tcps_sndacks++; 571111145Sjlemon else 572181803Sbz V_tcpstat.tcps_sndctrl++; 573181803Sbz V_tcpstat.tcps_sndtotal++; 574111145Sjlemon return (error); 575111145Sjlemon} 576169608Sandre 577169608Sandrestatic void 578169608Sandretcp_tw_2msl_reset(struct tcptw *tw, int rearm) 579169608Sandre{ 580183550Szec INIT_VNET_INET(curvnet); 581169608Sandre 582181803Sbz INP_INFO_WLOCK_ASSERT(&V_tcbinfo); 583178285Srwatson INP_WLOCK_ASSERT(tw->tw_inpcb); 584169608Sandre if (rearm) 585181803Sbz TAILQ_REMOVE(&V_twq_2msl, tw, tw_2msl); 586169608Sandre tw->tw_time = ticks + 2 * tcp_msl; 587181803Sbz TAILQ_INSERT_TAIL(&V_twq_2msl, tw, tw_2msl); 588169608Sandre} 589169608Sandre 590169608Sandrestatic void 591169608Sandretcp_tw_2msl_stop(struct tcptw *tw) 592169608Sandre{ 593183550Szec INIT_VNET_INET(curvnet); 594169608Sandre 595181803Sbz INP_INFO_WLOCK_ASSERT(&V_tcbinfo); 596181803Sbz TAILQ_REMOVE(&V_twq_2msl, tw, tw_2msl); 597169608Sandre} 598169608Sandre 599169608Sandrestruct tcptw * 600169608Sandretcp_tw_2msl_scan(int reuse) 601169608Sandre{ 602183550Szec INIT_VNET_INET(curvnet); 603169608Sandre struct tcptw *tw; 604169608Sandre 605181803Sbz INP_INFO_WLOCK_ASSERT(&V_tcbinfo); 606169608Sandre for (;;) { 607181803Sbz tw = TAILQ_FIRST(&V_twq_2msl); 608169608Sandre if (tw == NULL || (!reuse && tw->tw_time > ticks)) 609169608Sandre break; 610178285Srwatson INP_WLOCK(tw->tw_inpcb); 611169608Sandre tcp_twclose(tw, reuse); 612169608Sandre if (reuse) 613169608Sandre return (tw); 614169608Sandre } 615169608Sandre return (NULL); 616169608Sandre} 617