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tcp_input.c (86744) tcp_input.c (86764)
1/*
2 * Copyright (c) 1982, 1986, 1988, 1990, 1993, 1994, 1995
3 * The Regents of the University of California. All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright

--- 17 unchanged lines hidden (view full) ---

26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 *
33 * @(#)tcp_input.c 8.12 (Berkeley) 5/24/95
1/*
2 * Copyright (c) 1982, 1986, 1988, 1990, 1993, 1994, 1995
3 * The Regents of the University of California. All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright

--- 17 unchanged lines hidden (view full) ---

26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 *
33 * @(#)tcp_input.c 8.12 (Berkeley) 5/24/95
34 * $FreeBSD: head/sys/netinet/tcp_input.c 86744 2001-11-21 18:45:51Z jlemon $
34 * $FreeBSD: head/sys/netinet/tcp_input.c 86764 2001-11-22 04:50:44Z jlemon $
35 */
36
37#include "opt_ipfw.h" /* for ipfw_fwd */
38#include "opt_inet6.h"
39#include "opt_ipsec.h"
40#include "opt_tcpdebug.h"
41#include "opt_tcp_input.h"
42

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115SYSCTL_INT(_net_inet_tcp, OID_AUTO, blackhole, CTLFLAG_RW,
116 &blackhole, 0, "Do not send RST when dropping refused connections");
117
118int tcp_delack_enabled = 1;
119SYSCTL_INT(_net_inet_tcp, OID_AUTO, delayed_ack, CTLFLAG_RW,
120 &tcp_delack_enabled, 0,
121 "Delay ACK to try and piggyback it onto a data packet");
122
35 */
36
37#include "opt_ipfw.h" /* for ipfw_fwd */
38#include "opt_inet6.h"
39#include "opt_ipsec.h"
40#include "opt_tcpdebug.h"
41#include "opt_tcp_input.h"
42

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115SYSCTL_INT(_net_inet_tcp, OID_AUTO, blackhole, CTLFLAG_RW,
116 &blackhole, 0, "Do not send RST when dropping refused connections");
117
118int tcp_delack_enabled = 1;
119SYSCTL_INT(_net_inet_tcp, OID_AUTO, delayed_ack, CTLFLAG_RW,
120 &tcp_delack_enabled, 0,
121 "Delay ACK to try and piggyback it onto a data packet");
122
123int tcp_lq_overflow = 1;
124SYSCTL_INT(_net_inet_tcp, OID_AUTO, tcp_lq_overflow, CTLFLAG_RW,
125 &tcp_lq_overflow, 0,
126 "Listen Queue Overflow");
127
128#ifdef TCP_DROP_SYNFIN
129static int drop_synfin = 0;
130SYSCTL_INT(_net_inet_tcp, OID_AUTO, drop_synfin, CTLFLAG_RW,
131 &drop_synfin, 0, "Drop TCP packets with SYN+FIN set");
132#endif
133
134struct inpcbhead tcb;
135#define tcb6 tcb /* for KAME src sync over BSD*'s */
136struct inpcbinfo tcbinfo;
137
123#ifdef TCP_DROP_SYNFIN
124static int drop_synfin = 0;
125SYSCTL_INT(_net_inet_tcp, OID_AUTO, drop_synfin, CTLFLAG_RW,
126 &drop_synfin, 0, "Drop TCP packets with SYN+FIN set");
127#endif
128
129struct inpcbhead tcb;
130#define tcb6 tcb /* for KAME src sync over BSD*'s */
131struct inpcbinfo tcbinfo;
132
138static void tcp_dooptions __P((struct tcpcb *,
139 u_char *, int, struct tcphdr *, struct tcpopt *));
133static void tcp_dooptions __P((struct tcpopt *, u_char *, int, int));
140static void tcp_pulloutofband __P((struct socket *,
134static void tcp_pulloutofband __P((struct socket *,
141 struct tcphdr *, struct mbuf *, int));
135 struct tcphdr *, struct mbuf *, int));
142static int tcp_reass __P((struct tcpcb *, struct tcphdr *, int *,
143 struct mbuf *));
144static void tcp_xmit_timer __P((struct tcpcb *, int));
145static int tcp_newreno __P((struct tcpcb *, struct tcphdr *));
146
147/* Neighbor Discovery, Neighbor Unreachability Detection Upper layer hint. */
148#ifdef INET6
149#define ND6_HINT(tp) \

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339 u_char *optp = NULL;
340 int optlen = 0;
341 int len, tlen, off;
342 int drop_hdrlen;
343 register struct tcpcb *tp = 0;
344 register int thflags;
345 struct socket *so = 0;
346 int todrop, acked, ourfinisacked, needoutput = 0;
136static int tcp_reass __P((struct tcpcb *, struct tcphdr *, int *,
137 struct mbuf *));
138static void tcp_xmit_timer __P((struct tcpcb *, int));
139static int tcp_newreno __P((struct tcpcb *, struct tcphdr *));
140
141/* Neighbor Discovery, Neighbor Unreachability Detection Upper layer hint. */
142#ifdef INET6
143#define ND6_HINT(tp) \

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333 u_char *optp = NULL;
334 int optlen = 0;
335 int len, tlen, off;
336 int drop_hdrlen;
337 register struct tcpcb *tp = 0;
338 register int thflags;
339 struct socket *so = 0;
340 int todrop, acked, ourfinisacked, needoutput = 0;
347 struct in_addr laddr;
348#ifdef INET6
349 struct in6_addr laddr6;
350#endif
351 int dropsocket = 0;
352 int iss = 0;
353 u_long tiwin;
354 struct tcpopt to; /* options in this segment */
355 struct rmxp_tao *taop; /* pointer to our TAO cache entry */
356 struct rmxp_tao tao_noncached; /* in case there's no cached entry */
357#ifdef TCPDEBUG
358 short ostate = 0;
359#endif

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638 /* Unscale the window into a 32-bit value. */
639 if ((thflags & TH_SYN) == 0)
640 tiwin = th->th_win << tp->snd_scale;
641 else
642 tiwin = th->th_win;
643
644 so = inp->inp_socket;
645 if (so->so_options & (SO_DEBUG|SO_ACCEPTCONN)) {
341 int iss = 0;
342 u_long tiwin;
343 struct tcpopt to; /* options in this segment */
344 struct rmxp_tao *taop; /* pointer to our TAO cache entry */
345 struct rmxp_tao tao_noncached; /* in case there's no cached entry */
346#ifdef TCPDEBUG
347 short ostate = 0;
348#endif

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627 /* Unscale the window into a 32-bit value. */
628 if ((thflags & TH_SYN) == 0)
629 tiwin = th->th_win << tp->snd_scale;
630 else
631 tiwin = th->th_win;
632
633 so = inp->inp_socket;
634 if (so->so_options & (SO_DEBUG|SO_ACCEPTCONN)) {
635 struct in_conninfo inc;
646#ifdef TCPDEBUG
647 if (so->so_options & SO_DEBUG) {
648 ostate = tp->t_state;
649#ifdef INET6
650 if (isipv6)
651 bcopy((char *)ip6, (char *)tcp_saveipgen,
652 sizeof(*ip6));
653 else
654#endif /* INET6 */
655 bcopy((char *)ip, (char *)tcp_saveipgen, sizeof(*ip));
656 tcp_savetcp = *th;
657 }
658#endif
636#ifdef TCPDEBUG
637 if (so->so_options & SO_DEBUG) {
638 ostate = tp->t_state;
639#ifdef INET6
640 if (isipv6)
641 bcopy((char *)ip6, (char *)tcp_saveipgen,
642 sizeof(*ip6));
643 else
644#endif /* INET6 */
645 bcopy((char *)ip, (char *)tcp_saveipgen, sizeof(*ip));
646 tcp_savetcp = *th;
647 }
648#endif
659 if (so->so_options & SO_ACCEPTCONN) {
660 register struct tcpcb *tp0 = tp;
661 struct socket *so2;
662#ifdef IPSEC
663 struct socket *oso;
664#endif
649 /* skip if this isn't a listen socket */
650 if ((so->so_options & SO_ACCEPTCONN) == 0)
651 goto after_listen;
665#ifdef INET6
652#ifdef INET6
666 struct inpcb *oinp = sotoinpcb(so);
653 inc.inc_isipv6 = isipv6;
654 if (isipv6) {
655 inc.inc6_faddr = ip6->ip6_src;
656 inc.inc6_laddr = ip6->ip6_dst;
657 inc.inc6_route.ro_rt = NULL; /* XXX */
658
659 } else
667#endif /* INET6 */
660#endif /* INET6 */
661 {
662 inc.inc_faddr = ip->ip_src;
663 inc.inc_laddr = ip->ip_dst;
664 inc.inc_route.ro_rt = NULL; /* XXX */
665 }
666 inc.inc_fport = th->th_sport;
667 inc.inc_lport = th->th_dport;
668
668
669#ifndef IPSEC
670 /*
671 * Current IPsec implementation makes incorrect IPsec
672 * cache if this check is done here.
673 * So delay this until duplicated socket is created.
674 */
675 if ((thflags & (TH_RST|TH_ACK|TH_SYN)) != TH_SYN) {
676 /*
677 * Note: dropwithreset makes sure we don't
678 * send a RST in response to a RST.
679 */
680 if (thflags & TH_ACK) {
669 /*
670 * If the state is LISTEN then ignore segment if it contains
671 * a RST. If the segment contains an ACK then it is bad and
672 * send a RST. If it does not contain a SYN then it is not
673 * interesting; drop it.
674 *
675 * If the state is SYN_RECEIVED (syncache) and seg contains
676 * an ACK, but not for our SYN/ACK, send a RST. If the seg
677 * contains a RST, check the sequence number to see if it
678 * is a valid reset segment.
679 */
680 if ((thflags & (TH_RST|TH_ACK|TH_SYN)) != TH_SYN) {
681 if ((thflags & (TH_RST|TH_ACK|TH_SYN)) == TH_ACK) {
682 if (!syncache_expand(&inc, th, &so, m)) {
683 /*
684 * No syncache entry, or ACK was not
685 * for our SYN/ACK. Send a RST.
686 */
681 tcpstat.tcps_badsyn++;
682 rstreason = BANDLIM_RST_OPENPORT;
683 goto dropwithreset;
684 }
687 tcpstat.tcps_badsyn++;
688 rstreason = BANDLIM_RST_OPENPORT;
689 goto dropwithreset;
690 }
691 if (so == NULL)
692 /*
693 * Could not complete 3-way handshake,
694 * connection is being closed down, and
695 * syncache will free mbuf.
696 */
697 return;
698 /*
699 * Socket is created in state SYN_RECEIVED.
700 * Continue processing segment.
701 */
702 inp = sotoinpcb(so);
703 tp = intotcpcb(inp);
704 /*
705 * This is what would have happened in
706 * tcp_ouput() when the SYN,ACK was sent.
707 */
708 tp->snd_up = tp->snd_una;
709 tp->snd_max = tp->snd_nxt = tp->iss + 1;
710 tp->last_ack_sent = tp->rcv_nxt;
711/*
712 * XXX possible bug - it doesn't appear that tp->snd_wnd is unscaled
713 * until the _second_ ACK is received:
714 * rcv SYN (set wscale opts) --> send SYN/ACK, set snd_wnd = window.
715 * rcv ACK, calculate tiwin --> process SYN_RECEIVED, determine wscale,
716 * move to ESTAB, set snd_wnd to tiwin.
717 */
718 tp->snd_wnd = tiwin; /* unscaled */
719 goto after_listen;
720 }
721 if (thflags & TH_RST) {
722 syncache_chkrst(&inc, th);
685 goto drop;
686 }
723 goto drop;
724 }
687#endif
725 if (thflags & TH_ACK) {
726 syncache_badack(&inc);
727 tcpstat.tcps_badsyn++;
728 rstreason = BANDLIM_RST_OPENPORT;
729 goto dropwithreset;
730 }
731 goto drop;
732 }
688
733
734 /*
735 * Segment's flags are (SYN) or (SYN|FIN).
736 */
689#ifdef INET6
737#ifdef INET6
690 /*
691 * If deprecated address is forbidden,
692 * we do not accept SYN to deprecated interface
693 * address to prevent any new inbound connection from
694 * getting established.
695 * When we do not accept SYN, we send a TCP RST,
696 * with deprecated source address (instead of dropping
697 * it). We compromise it as it is much better for peer
698 * to send a RST, and RST will be the final packet
699 * for the exchange.
700 *
701 * If we do not forbid deprecated addresses, we accept
702 * the SYN packet. RFC2462 does not suggest dropping
703 * SYN in this case.
704 * If we decipher RFC2462 5.5.4, it says like this:
705 * 1. use of deprecated addr with existing
706 * communication is okay - "SHOULD continue to be
707 * used"
708 * 2. use of it with new communication:
709 * (2a) "SHOULD NOT be used if alternate address
710 * with sufficient scope is available"
711 * (2b) nothing mentioned otherwise.
712 * Here we fall into (2b) case as we have no choice in
713 * our source address selection - we must obey the peer.
714 *
715 * The wording in RFC2462 is confusing, and there are
716 * multiple description text for deprecated address
717 * handling - worse, they are not exactly the same.
718 * I believe 5.5.4 is the best one, so we follow 5.5.4.
719 */
720 if (isipv6 && !ip6_use_deprecated) {
721 struct in6_ifaddr *ia6;
738 /*
739 * If deprecated address is forbidden,
740 * we do not accept SYN to deprecated interface
741 * address to prevent any new inbound connection from
742 * getting established.
743 * When we do not accept SYN, we send a TCP RST,
744 * with deprecated source address (instead of dropping
745 * it). We compromise it as it is much better for peer
746 * to send a RST, and RST will be the final packet
747 * for the exchange.
748 *
749 * If we do not forbid deprecated addresses, we accept
750 * the SYN packet. RFC2462 does not suggest dropping
751 * SYN in this case.
752 * If we decipher RFC2462 5.5.4, it says like this:
753 * 1. use of deprecated addr with existing
754 * communication is okay - "SHOULD continue to be
755 * used"
756 * 2. use of it with new communication:
757 * (2a) "SHOULD NOT be used if alternate address
758 * with sufficient scope is available"
759 * (2b) nothing mentioned otherwise.
760 * Here we fall into (2b) case as we have no choice in
761 * our source address selection - we must obey the peer.
762 *
763 * The wording in RFC2462 is confusing, and there are
764 * multiple description text for deprecated address
765 * handling - worse, they are not exactly the same.
766 * I believe 5.5.4 is the best one, so we follow 5.5.4.
767 */
768 if (isipv6 && !ip6_use_deprecated) {
769 struct in6_ifaddr *ia6;
722
770
723 if ((ia6 = ip6_getdstifaddr(m)) &&
724 (ia6->ia6_flags & IN6_IFF_DEPRECATED)) {
725 tp = NULL;
726 rstreason = BANDLIM_RST_OPENPORT;
727 goto dropwithreset;
728 }
771 if ((ia6 = ip6_getdstifaddr(m)) &&
772 (ia6->ia6_flags & IN6_IFF_DEPRECATED)) {
773 tp = NULL;
774 rstreason = BANDLIM_RST_OPENPORT;
775 goto dropwithreset;
729 }
776 }
777 }
730#endif
778#endif
731
732 so2 = sonewconn(so, 0);
733 if (so2 == 0) {
734 /*
735 * If we were unable to create a new socket
736 * for this SYN, we call sodropablereq to
737 * see if there are any other sockets we
738 * can kick out of the listen queue. If
739 * so, we'll silently drop the socket
740 * sodropablereq told us to drop and
741 * create a new one.
742 *
743 * If sodropablereq returns 0, we'll
744 * simply drop the incoming SYN, as we
745 * can not allocate a socket for it.
746 */
747 tcpstat.tcps_listendrop++;
748 so2 = sodropablereq(so);
749 if (so2) {
750 if (tcp_lq_overflow)
751 sototcpcb(so2)->t_flags |=
752 TF_LQ_OVERFLOW;
753 tcp_close(sototcpcb(so2));
754 so2 = sonewconn(so, 0);
755 }
756 if (!so2)
757 goto drop;
758 }
759#ifdef IPSEC
760 oso = so;
761#endif
762 so = so2;
763 /*
764 * This is ugly, but ....
765 *
766 * Mark socket as temporary until we're
767 * committed to keeping it. The code at
768 * ``drop'' and ``dropwithreset'' check the
769 * flag dropsocket to see if the temporary
770 * socket created here should be discarded.
771 * We mark the socket as discardable until
772 * we're committed to it below in TCPS_LISTEN.
773 */
774 dropsocket++;
775 inp = (struct inpcb *)so->so_pcb;
779 /*
780 * If it is from this socket, drop it, it must be forged.
781 * Don't bother responding if the destination was a broadcast.
782 */
783 if (th->th_dport == th->th_sport) {
776#ifdef INET6
784#ifdef INET6
777 if (isipv6)
778 inp->in6p_laddr = ip6->ip6_dst;
779 else {
780 inp->inp_vflag &= ~INP_IPV6;
781 inp->inp_vflag |= INP_IPV4;
785 if (isipv6) {
786 if (IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst,
787 &ip6->ip6_src))
788 goto drop;
789 } else
782#endif /* INET6 */
790#endif /* INET6 */
783 inp->inp_laddr = ip->ip_dst;
791 if (ip->ip_dst.s_addr == ip->ip_src.s_addr)
792 goto drop;
793 }
794 /*
795 * RFC1122 4.2.3.10, p. 104: discard bcast/mcast SYN
796 * in_broadcast() should never return true on a received
797 * packet with M_BCAST not set.
798 *
799 * Packets with a multicast source address should also
800 * be discarded.
801 */
802 if (m->m_flags & (M_BCAST|M_MCAST))
803 goto drop;
784#ifdef INET6
804#ifdef INET6
785 }
786#endif /* INET6 */
787 inp->inp_lport = th->th_dport;
788 if (in_pcbinshash(inp) != 0) {
805 if (isipv6) {
806 if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst) ||
807 IN6_IS_ADDR_MULTICAST(&ip6->ip6_src))
808 goto drop;
809 } else
810#endif
811 if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr)) ||
812 IN_MULTICAST(ntohl(ip->ip_src.s_addr)) ||
813 ip->ip_src.s_addr == htonl(INADDR_BROADCAST))
814 goto drop;
815 /*
816 * SYN appears to be valid; create compressed TCP state
817 * for syncache, or perform t/tcp connection.
818 */
819 if (so->so_qlen <= so->so_qlimit) {
820 tcp_dooptions(&to, optp, optlen, 1);
821 if (!syncache_add(&inc, &to, th, &so, m))
822 goto drop;
823 if (so == NULL)
789 /*
824 /*
790 * Undo the assignments above if we failed to
791 * put the PCB on the hash lists.
825 * Entry added to syncache, mbuf used to
826 * send SYN,ACK packet.
792 */
827 */
793#ifdef INET6
794 if (isipv6)
795 inp->in6p_laddr = in6addr_any;
796 else
797#endif /* INET6 */
798 inp->inp_laddr.s_addr = INADDR_ANY;
799 inp->inp_lport = 0;
800 goto drop;
801 }
802#ifdef IPSEC
828 return;
803 /*
829 /*
804 * To avoid creating incorrectly cached IPsec
805 * association, this is need to be done here.
806 *
807 * Subject: (KAME-snap 748)
808 * From: Wayne Knowles <w.knowles@niwa.cri.nz>
809 * ftp://ftp.kame.net/pub/mail-list/snap-users/748
830 * Segment passed TAO tests.
810 */
831 */
811 if ((thflags & (TH_RST|TH_ACK|TH_SYN)) != TH_SYN) {
812 /*
813 * Note: dropwithreset makes sure we don't
814 * send a RST in response to a RST.
815 */
816 if (thflags & TH_ACK) {
817 tcpstat.tcps_badsyn++;
818 rstreason = BANDLIM_RST_OPENPORT;
819 goto dropwithreset;
820 }
821 goto drop;
822 }
832 inp = sotoinpcb(so);
833 tp = intotcpcb(inp);
834 tp->snd_wnd = tiwin;
835 tp->t_starttime = ticks;
836 tp->t_state = TCPS_ESTABLISHED;
837
838 /*
839 * If there is a FIN, or if there is data and the
840 * connection is local, then delay SYN,ACK(SYN) in
841 * the hope of piggy-backing it on a response
842 * segment. Otherwise must send ACK now in case
843 * the other side is slow starting.
844 */
845 if (DELAY_ACK(tp) && ((thflags & TH_FIN) ||
846 (tlen != 0 &&
847#ifdef INET6
848 ((isipv6 && in6_localaddr(&inp->in6p_faddr))
849 ||
850 (!isipv6 &&
823#endif
851#endif
852 in_localaddr(inp->inp_faddr)
824#ifdef INET6
853#ifdef INET6
825 if (isipv6) {
826 /*
827 * Inherit socket options from the listening
828 * socket.
829 * Note that in6p_inputopts are not (even
830 * should not be) copied, since it stores
831 * previously received options and is used to
832 * detect if each new option is different than
833 * the previous one and hence should be passed
834 * to a user.
835 * If we copied in6p_inputopts, a user would
836 * not be able to receive options just after
837 * calling the accept system call.
838 */
839 inp->inp_flags |=
840 oinp->inp_flags & INP_CONTROLOPTS;
841 if (oinp->in6p_outputopts)
842 inp->in6p_outputopts =
843 ip6_copypktopts(oinp->in6p_outputopts,
844 M_NOWAIT);
845 } else
846#endif /* INET6 */
847 inp->inp_options = ip_srcroute();
848#ifdef IPSEC
849 /* copy old policy into new socket's */
850 if (ipsec_copy_policy(sotoinpcb(oso)->inp_sp,
851 inp->inp_sp))
852 printf("tcp_input: could not copy policy\n");
854 ))
853#endif
855#endif
854 tp = intotcpcb(inp);
855 tp->t_state = TCPS_LISTEN;
856 tp->t_flags |= tp0->t_flags & (TF_NOPUSH|TF_NOOPT);
856 ))) {
857 callout_reset(tp->tt_delack, tcp_delacktime,
858 tcp_timer_delack, tp);
859 tp->t_flags |= TF_NEEDSYN;
860 } else
861 tp->t_flags |= (TF_ACKNOW | TF_NEEDSYN);
857
862
858 /* Compute proper scaling value from buffer space */
859 while (tp->request_r_scale < TCP_MAX_WINSHIFT &&
860 TCP_MAXWIN << tp->request_r_scale <
861 so->so_rcv.sb_hiwat)
862 tp->request_r_scale++;
863 tcpstat.tcps_connects++;
864 soisconnected(so);
865 goto trimthenstep6;
863 }
866 }
867 goto drop;
864 }
868 }
869after_listen:
865
870
871/* XXX temp debugging */
872 /* should not happen - syncache should pick up these connections */
873 if (tp->t_state == TCPS_LISTEN)
874 panic("tcp_input: TCPS_LISTEN");
875
866 /*
867 * Segment received on connection.
868 * Reset idle time and keep-alive timer.
869 */
870 tp->t_rcvtime = ticks;
871 if (TCPS_HAVEESTABLISHED(tp->t_state))
872 callout_reset(tp->tt_keep, tcp_keepidle, tcp_timer_keep, tp);
873
874 /*
876 /*
877 * Segment received on connection.
878 * Reset idle time and keep-alive timer.
879 */
880 tp->t_rcvtime = ticks;
881 if (TCPS_HAVEESTABLISHED(tp->t_state))
882 callout_reset(tp->tt_keep, tcp_keepidle, tcp_timer_keep, tp);
883
884 /*
875 * Process options if not in LISTEN state,
876 * else do it below (after getting remote address).
885 * Process options.
886 * XXX this is tradtitional behavior, may need to be cleaned up.
877 */
887 */
878 if (tp->t_state != TCPS_LISTEN)
879 tcp_dooptions(tp, optp, optlen, th, &to);
888 tcp_dooptions(&to, optp, optlen, thflags & TH_SYN);
889 if (thflags & TH_SYN) {
890 if (to.to_flags & TOF_SCALE) {
891 tp->t_flags |= TF_RCVD_SCALE;
892 tp->requested_s_scale = to.to_requested_s_scale;
893 }
894 if (to.to_flags & TOF_TS) {
895 tp->t_flags |= TF_RCVD_TSTMP;
896 tp->ts_recent = to.to_tsval;
897 tp->ts_recent_age = ticks;
898 }
899 if (to.to_flags & (TOF_CC|TOF_CCNEW))
900 tp->t_flags |= TF_RCVD_CC;
901 if (to.to_flags & TOF_MSS)
902 tcp_mss(tp, to.to_mss);
903 }
880
881 /*
882 * Header prediction: check for the two common cases
883 * of a uni-directional data xfer. If the packet has
884 * no control flags, is in-sequence, the window didn't
885 * change and we're not retransmitting, it's a
886 * candidate. If the length is zero and the ack moved
887 * forward, we're the sender side of the xfer. Just

--- 5 unchanged lines hidden (view full) ---

893 * the socket buffer and note that we need a delayed ack.
894 * Make sure that the hidden state-flags are also off.
895 * Since we check for TCPS_ESTABLISHED above, it can only
896 * be TH_NEEDSYN.
897 */
898 if (tp->t_state == TCPS_ESTABLISHED &&
899 (thflags & (TH_SYN|TH_FIN|TH_RST|TH_URG|TH_ACK)) == TH_ACK &&
900 ((tp->t_flags & (TF_NEEDSYN|TF_NEEDFIN)) == 0) &&
904
905 /*
906 * Header prediction: check for the two common cases
907 * of a uni-directional data xfer. If the packet has
908 * no control flags, is in-sequence, the window didn't
909 * change and we're not retransmitting, it's a
910 * candidate. If the length is zero and the ack moved
911 * forward, we're the sender side of the xfer. Just

--- 5 unchanged lines hidden (view full) ---

917 * the socket buffer and note that we need a delayed ack.
918 * Make sure that the hidden state-flags are also off.
919 * Since we check for TCPS_ESTABLISHED above, it can only
920 * be TH_NEEDSYN.
921 */
922 if (tp->t_state == TCPS_ESTABLISHED &&
923 (thflags & (TH_SYN|TH_FIN|TH_RST|TH_URG|TH_ACK)) == TH_ACK &&
924 ((tp->t_flags & (TF_NEEDSYN|TF_NEEDFIN)) == 0) &&
901 ((to.to_flag & TOF_TS) == 0 ||
925 ((to.to_flags & TOF_TS) == 0 ||
902 TSTMP_GEQ(to.to_tsval, tp->ts_recent)) &&
903 /*
904 * Using the CC option is compulsory if once started:
905 * the segment is OK if no T/TCP was negotiated or
906 * if the segment has a CC option equal to CCrecv
907 */
908 ((tp->t_flags & (TF_REQ_CC|TF_RCVD_CC)) != (TF_REQ_CC|TF_RCVD_CC) ||
926 TSTMP_GEQ(to.to_tsval, tp->ts_recent)) &&
927 /*
928 * Using the CC option is compulsory if once started:
929 * the segment is OK if no T/TCP was negotiated or
930 * if the segment has a CC option equal to CCrecv
931 */
932 ((tp->t_flags & (TF_REQ_CC|TF_RCVD_CC)) != (TF_REQ_CC|TF_RCVD_CC) ||
909 ((to.to_flag & TOF_CC) != 0 && to.to_cc == tp->cc_recv)) &&
933 ((to.to_flags & TOF_CC) != 0 && to.to_cc == tp->cc_recv)) &&
910 th->th_seq == tp->rcv_nxt &&
911 tiwin && tiwin == tp->snd_wnd &&
912 tp->snd_nxt == tp->snd_max) {
913
914 /*
915 * If last ACK falls within this segment's sequence numbers,
916 * record the timestamp.
917 * NOTE that the test is modified according to the latest
918 * proposal of the tcplw@cray.com list (Braden 1993/04/26).
919 */
934 th->th_seq == tp->rcv_nxt &&
935 tiwin && tiwin == tp->snd_wnd &&
936 tp->snd_nxt == tp->snd_max) {
937
938 /*
939 * If last ACK falls within this segment's sequence numbers,
940 * record the timestamp.
941 * NOTE that the test is modified according to the latest
942 * proposal of the tcplw@cray.com list (Braden 1993/04/26).
943 */
920 if ((to.to_flag & TOF_TS) != 0 &&
944 if ((to.to_flags & TOF_TS) != 0 &&
921 SEQ_LEQ(th->th_seq, tp->last_ack_sent)) {
922 tp->ts_recent_age = ticks;
923 tp->ts_recent = to.to_tsval;
924 }
925
926 if (tlen == 0) {
927 if (SEQ_GT(th->th_ack, tp->snd_una) &&
928 SEQ_LEQ(th->th_ack, tp->snd_max) &&

--- 9 unchanged lines hidden (view full) ---

938 if (tp->t_rxtshift == 1 &&
939 ticks < tp->t_badrxtwin) {
940 tp->snd_cwnd = tp->snd_cwnd_prev;
941 tp->snd_ssthresh =
942 tp->snd_ssthresh_prev;
943 tp->snd_nxt = tp->snd_max;
944 tp->t_badrxtwin = 0;
945 }
945 SEQ_LEQ(th->th_seq, tp->last_ack_sent)) {
946 tp->ts_recent_age = ticks;
947 tp->ts_recent = to.to_tsval;
948 }
949
950 if (tlen == 0) {
951 if (SEQ_GT(th->th_ack, tp->snd_una) &&
952 SEQ_LEQ(th->th_ack, tp->snd_max) &&

--- 9 unchanged lines hidden (view full) ---

962 if (tp->t_rxtshift == 1 &&
963 ticks < tp->t_badrxtwin) {
964 tp->snd_cwnd = tp->snd_cwnd_prev;
965 tp->snd_ssthresh =
966 tp->snd_ssthresh_prev;
967 tp->snd_nxt = tp->snd_max;
968 tp->t_badrxtwin = 0;
969 }
946 if ((to.to_flag & TOF_TS) != 0)
970 if ((to.to_flags & TOF_TS) != 0)
947 tcp_xmit_timer(tp,
948 ticks - to.to_tsecr + 1);
949 else if (tp->t_rtttime &&
950 SEQ_GT(th->th_ack, tp->t_rtseq))
951 tcp_xmit_timer(tp, ticks - tp->t_rtttime);
952 acked = th->th_ack - tp->snd_una;
953 tcpstat.tcps_rcvackpack++;
954 tcpstat.tcps_rcvackbyte += acked;

--- 65 unchanged lines hidden (view full) ---

1020 if (win < 0)
1021 win = 0;
1022 tp->rcv_wnd = imax(win, (int)(tp->rcv_adv - tp->rcv_nxt));
1023 }
1024
1025 switch (tp->t_state) {
1026
1027 /*
971 tcp_xmit_timer(tp,
972 ticks - to.to_tsecr + 1);
973 else if (tp->t_rtttime &&
974 SEQ_GT(th->th_ack, tp->t_rtseq))
975 tcp_xmit_timer(tp, ticks - tp->t_rtttime);
976 acked = th->th_ack - tp->snd_una;
977 tcpstat.tcps_rcvackpack++;
978 tcpstat.tcps_rcvackbyte += acked;

--- 65 unchanged lines hidden (view full) ---

1044 if (win < 0)
1045 win = 0;
1046 tp->rcv_wnd = imax(win, (int)(tp->rcv_adv - tp->rcv_nxt));
1047 }
1048
1049 switch (tp->t_state) {
1050
1051 /*
1028 * If the state is LISTEN then ignore segment if it contains an RST.
1029 * If the segment contains an ACK then it is bad and send a RST.
1030 * If it does not contain a SYN then it is not interesting; drop it.
1031 * If it is from this socket, drop it, it must be forged.
1032 * Don't bother responding if the destination was a broadcast.
1033 * Otherwise initialize tp->rcv_nxt, and tp->irs, select an initial
1034 * tp->iss, and send a segment:
1035 * <SEQ=ISS><ACK=RCV_NXT><CTL=SYN,ACK>
1036 * Also initialize tp->snd_nxt to tp->iss+1 and tp->snd_una to tp->iss.
1037 * Fill in remote peer address fields if not previously specified.
1038 * Enter SYN_RECEIVED state, and process any other fields of this
1039 * segment in this state.
1040 */
1041 case TCPS_LISTEN: {
1042 register struct sockaddr_in *sin;
1043#ifdef INET6
1044 register struct sockaddr_in6 *sin6;
1045#endif
1046
1047 if (thflags & TH_RST)
1048 goto drop;
1049 if (thflags & TH_ACK) {
1050 rstreason = BANDLIM_RST_OPENPORT;
1051 goto dropwithreset;
1052 }
1053 if ((thflags & TH_SYN) == 0)
1054 goto drop;
1055 if (th->th_dport == th->th_sport) {
1056#ifdef INET6
1057 if (isipv6) {
1058 if (IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst,
1059 &ip6->ip6_src))
1060 goto drop;
1061 } else
1062#endif /* INET6 */
1063 if (ip->ip_dst.s_addr == ip->ip_src.s_addr)
1064 goto drop;
1065 }
1066 /*
1067 * RFC1122 4.2.3.10, p. 104: discard bcast/mcast SYN
1068 * in_broadcast() should never return true on a received
1069 * packet with M_BCAST not set.
1070 *
1071 * Packets with a multicast source address should also
1072 * be discarded.
1073 */
1074 if (m->m_flags & (M_BCAST|M_MCAST))
1075 goto drop;
1076#ifdef INET6
1077 if (isipv6) {
1078 if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst) ||
1079 IN6_IS_ADDR_MULTICAST(&ip6->ip6_src))
1080 goto drop;
1081 } else
1082#endif
1083 if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr)) ||
1084 IN_MULTICAST(ntohl(ip->ip_src.s_addr)) ||
1085 ip->ip_src.s_addr == htonl(INADDR_BROADCAST))
1086 goto drop;
1087#ifdef INET6
1088 if (isipv6) {
1089 MALLOC(sin6, struct sockaddr_in6 *, sizeof *sin6,
1090 M_SONAME, M_NOWAIT | M_ZERO);
1091 if (sin6 == NULL)
1092 goto drop;
1093 sin6->sin6_family = AF_INET6;
1094 sin6->sin6_len = sizeof(*sin6);
1095 sin6->sin6_addr = ip6->ip6_src;
1096 sin6->sin6_port = th->th_sport;
1097 laddr6 = inp->in6p_laddr;
1098 if (IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_laddr))
1099 inp->in6p_laddr = ip6->ip6_dst;
1100 if (in6_pcbconnect(inp, (struct sockaddr *)sin6,
1101 thread0)) {
1102 inp->in6p_laddr = laddr6;
1103 FREE(sin6, M_SONAME);
1104 goto drop;
1105 }
1106 FREE(sin6, M_SONAME);
1107 } else
1108#endif
1109 {
1110 MALLOC(sin, struct sockaddr_in *, sizeof *sin, M_SONAME,
1111 M_NOWAIT);
1112 if (sin == NULL)
1113 goto drop;
1114 sin->sin_family = AF_INET;
1115 sin->sin_len = sizeof(*sin);
1116 sin->sin_addr = ip->ip_src;
1117 sin->sin_port = th->th_sport;
1118 bzero((caddr_t)sin->sin_zero, sizeof(sin->sin_zero));
1119 laddr = inp->inp_laddr;
1120 if (inp->inp_laddr.s_addr == INADDR_ANY)
1121 inp->inp_laddr = ip->ip_dst;
1122 if (in_pcbconnect(inp, (struct sockaddr *)sin, thread0)) {
1123 inp->inp_laddr = laddr;
1124 FREE(sin, M_SONAME);
1125 goto drop;
1126 }
1127 FREE(sin, M_SONAME);
1128 }
1129 if ((taop = tcp_gettaocache(inp)) == NULL) {
1130 taop = &tao_noncached;
1131 bzero(taop, sizeof(*taop));
1132 }
1133 tcp_dooptions(tp, optp, optlen, th, &to);
1134 if (iss)
1135 tp->iss = iss;
1136 else {
1137 tp->iss = tcp_new_isn(tp);
1138 }
1139 tp->irs = th->th_seq;
1140 tcp_sendseqinit(tp);
1141 tcp_rcvseqinit(tp);
1142 /*
1143 * Initialization of the tcpcb for transaction;
1144 * set SND.WND = SEG.WND,
1145 * initialize CCsend and CCrecv.
1146 */
1147 tp->snd_wnd = tiwin; /* initial send-window */
1148 tp->cc_send = CC_INC(tcp_ccgen);
1149 tp->cc_recv = to.to_cc;
1150 /*
1151 * Perform TAO test on incoming CC (SEG.CC) option, if any.
1152 * - compare SEG.CC against cached CC from the same host,
1153 * if any.
1154 * - if SEG.CC > chached value, SYN must be new and is accepted
1155 * immediately: save new CC in the cache, mark the socket
1156 * connected, enter ESTABLISHED state, turn on flag to
1157 * send a SYN in the next segment.
1158 * A virtual advertised window is set in rcv_adv to
1159 * initialize SWS prevention. Then enter normal segment
1160 * processing: drop SYN, process data and FIN.
1161 * - otherwise do a normal 3-way handshake.
1162 */
1163 if ((to.to_flag & TOF_CC) != 0) {
1164 if (((tp->t_flags & TF_NOPUSH) != 0) &&
1165 taop->tao_cc != 0 && CC_GT(to.to_cc, taop->tao_cc)) {
1166
1167 taop->tao_cc = to.to_cc;
1168 tp->t_starttime = ticks;
1169 tp->t_state = TCPS_ESTABLISHED;
1170
1171 /*
1172 * If there is a FIN, or if there is data and the
1173 * connection is local, then delay SYN,ACK(SYN) in
1174 * the hope of piggy-backing it on a response
1175 * segment. Otherwise must send ACK now in case
1176 * the other side is slow starting.
1177 */
1178 if (DELAY_ACK(tp) && ((thflags & TH_FIN) ||
1179 (tlen != 0 &&
1180#ifdef INET6
1181 ((isipv6 && in6_localaddr(&inp->in6p_faddr))
1182 ||
1183 (!isipv6 &&
1184#endif
1185 in_localaddr(inp->inp_faddr)
1186#ifdef INET6
1187 ))
1188#endif
1189 ))) {
1190 callout_reset(tp->tt_delack, tcp_delacktime,
1191 tcp_timer_delack, tp);
1192 tp->t_flags |= TF_NEEDSYN;
1193 } else
1194 tp->t_flags |= (TF_ACKNOW | TF_NEEDSYN);
1195
1196 /*
1197 * Limit the `virtual advertised window' to TCP_MAXWIN
1198 * here. Even if we requested window scaling, it will
1199 * become effective only later when our SYN is acked.
1200 */
1201 tp->rcv_adv += min(tp->rcv_wnd, TCP_MAXWIN);
1202 tcpstat.tcps_connects++;
1203 soisconnected(so);
1204 callout_reset(tp->tt_keep, tcp_keepinit,
1205 tcp_timer_keep, tp);
1206 dropsocket = 0; /* committed to socket */
1207 tcpstat.tcps_accepts++;
1208 goto trimthenstep6;
1209 }
1210 /* else do standard 3-way handshake */
1211 } else {
1212 /*
1213 * No CC option, but maybe CC.NEW:
1214 * invalidate cached value.
1215 */
1216 taop->tao_cc = 0;
1217 }
1218 /*
1219 * TAO test failed or there was no CC option,
1220 * do a standard 3-way handshake.
1221 */
1222 tp->t_flags |= TF_ACKNOW;
1223 tp->t_state = TCPS_SYN_RECEIVED;
1224 callout_reset(tp->tt_keep, tcp_keepinit, tcp_timer_keep, tp);
1225 dropsocket = 0; /* committed to socket */
1226 tcpstat.tcps_accepts++;
1227 goto trimthenstep6;
1228 }
1229
1230 /*
1231 * If the state is SYN_RECEIVED:
1232 * if seg contains an ACK, but not for our SYN/ACK, send a RST.
1233 */
1234 case TCPS_SYN_RECEIVED:
1235 if ((thflags & TH_ACK) &&
1236 (SEQ_LEQ(th->th_ack, tp->snd_una) ||
1237 SEQ_GT(th->th_ack, tp->snd_max))) {
1238 rstreason = BANDLIM_RST_OPENPORT;

--- 9 unchanged lines hidden (view full) ---

1248 * Otherwise this is an acceptable SYN segment
1249 * initialize tp->rcv_nxt and tp->irs
1250 * if seg contains ack then advance tp->snd_una
1251 * if SYN has been acked change to ESTABLISHED else SYN_RCVD state
1252 * arrange for segment to be acked (eventually)
1253 * continue processing rest of data/controls, beginning with URG
1254 */
1255 case TCPS_SYN_SENT:
1052 * If the state is SYN_RECEIVED:
1053 * if seg contains an ACK, but not for our SYN/ACK, send a RST.
1054 */
1055 case TCPS_SYN_RECEIVED:
1056 if ((thflags & TH_ACK) &&
1057 (SEQ_LEQ(th->th_ack, tp->snd_una) ||
1058 SEQ_GT(th->th_ack, tp->snd_max))) {
1059 rstreason = BANDLIM_RST_OPENPORT;

--- 9 unchanged lines hidden (view full) ---

1069 * Otherwise this is an acceptable SYN segment
1070 * initialize tp->rcv_nxt and tp->irs
1071 * if seg contains ack then advance tp->snd_una
1072 * if SYN has been acked change to ESTABLISHED else SYN_RCVD state
1073 * arrange for segment to be acked (eventually)
1074 * continue processing rest of data/controls, beginning with URG
1075 */
1076 case TCPS_SYN_SENT:
1256 if ((taop = tcp_gettaocache(inp)) == NULL) {
1077 if ((taop = tcp_gettaocache(&inp->inp_inc)) == NULL) {
1257 taop = &tao_noncached;
1258 bzero(taop, sizeof(*taop));
1259 }
1260
1261 if ((thflags & TH_ACK) &&
1262 (SEQ_LEQ(th->th_ack, tp->iss) ||
1263 SEQ_GT(th->th_ack, tp->snd_max))) {
1264 /*

--- 27 unchanged lines hidden (view full) ---

1292 /*
1293 * Our SYN was acked. If segment contains CC.ECHO
1294 * option, check it to make sure this segment really
1295 * matches our SYN. If not, just drop it as old
1296 * duplicate, but send an RST if we're still playing
1297 * by the old rules. If no CC.ECHO option, make sure
1298 * we don't get fooled into using T/TCP.
1299 */
1078 taop = &tao_noncached;
1079 bzero(taop, sizeof(*taop));
1080 }
1081
1082 if ((thflags & TH_ACK) &&
1083 (SEQ_LEQ(th->th_ack, tp->iss) ||
1084 SEQ_GT(th->th_ack, tp->snd_max))) {
1085 /*

--- 27 unchanged lines hidden (view full) ---

1113 /*
1114 * Our SYN was acked. If segment contains CC.ECHO
1115 * option, check it to make sure this segment really
1116 * matches our SYN. If not, just drop it as old
1117 * duplicate, but send an RST if we're still playing
1118 * by the old rules. If no CC.ECHO option, make sure
1119 * we don't get fooled into using T/TCP.
1120 */
1300 if (to.to_flag & TOF_CCECHO) {
1121 if (to.to_flags & TOF_CCECHO) {
1301 if (tp->cc_send != to.to_ccecho) {
1302 if (taop->tao_ccsent != 0)
1303 goto drop;
1304 else {
1305 rstreason = BANDLIM_UNLIMITED;
1306 goto dropwithreset;
1307 }
1308 }

--- 45 unchanged lines hidden (view full) ---

1354 * a cached CC, apply TAO test; if it succeeds, connection is
1355 * half-synchronized. Otherwise, do 3-way handshake:
1356 * SYN-SENT -> SYN-RECEIVED
1357 * SYN-SENT* -> SYN-RECEIVED*
1358 * If there was no CC option, clear cached CC value.
1359 */
1360 tp->t_flags |= TF_ACKNOW;
1361 callout_stop(tp->tt_rexmt);
1122 if (tp->cc_send != to.to_ccecho) {
1123 if (taop->tao_ccsent != 0)
1124 goto drop;
1125 else {
1126 rstreason = BANDLIM_UNLIMITED;
1127 goto dropwithreset;
1128 }
1129 }

--- 45 unchanged lines hidden (view full) ---

1175 * a cached CC, apply TAO test; if it succeeds, connection is
1176 * half-synchronized. Otherwise, do 3-way handshake:
1177 * SYN-SENT -> SYN-RECEIVED
1178 * SYN-SENT* -> SYN-RECEIVED*
1179 * If there was no CC option, clear cached CC value.
1180 */
1181 tp->t_flags |= TF_ACKNOW;
1182 callout_stop(tp->tt_rexmt);
1362 if (to.to_flag & TOF_CC) {
1183 if (to.to_flags & TOF_CC) {
1363 if (taop->tao_cc != 0 &&
1364 CC_GT(to.to_cc, taop->tao_cc)) {
1365 /*
1366 * update cache and make transition:
1367 * SYN-SENT -> ESTABLISHED*
1368 * SYN-SENT* -> FIN-WAIT-1*
1369 */
1370 taop->tao_cc = to.to_cc;

--- 58 unchanged lines hidden (view full) ---

1429 *
1430 * else must be old SYN; drop it.
1431 * else do normal processing.
1432 */
1433 case TCPS_LAST_ACK:
1434 case TCPS_CLOSING:
1435 case TCPS_TIME_WAIT:
1436 if ((thflags & TH_SYN) &&
1184 if (taop->tao_cc != 0 &&
1185 CC_GT(to.to_cc, taop->tao_cc)) {
1186 /*
1187 * update cache and make transition:
1188 * SYN-SENT -> ESTABLISHED*
1189 * SYN-SENT* -> FIN-WAIT-1*
1190 */
1191 taop->tao_cc = to.to_cc;

--- 58 unchanged lines hidden (view full) ---

1250 *
1251 * else must be old SYN; drop it.
1252 * else do normal processing.
1253 */
1254 case TCPS_LAST_ACK:
1255 case TCPS_CLOSING:
1256 case TCPS_TIME_WAIT:
1257 if ((thflags & TH_SYN) &&
1437 (to.to_flag & TOF_CC) && tp->cc_recv != 0) {
1258 (to.to_flags & TOF_CC) && tp->cc_recv != 0) {
1438 if (tp->t_state == TCPS_TIME_WAIT &&
1439 (ticks - tp->t_starttime) > tcp_msl) {
1440 rstreason = BANDLIM_UNLIMITED;
1441 goto dropwithreset;
1442 }
1443 if (CC_GT(to.to_cc, tp->cc_recv)) {
1444 tp = tcp_close(tp);
1445 goto findpcb;

--- 91 unchanged lines hidden (view full) ---

1537 }
1538 goto drop;
1539 }
1540
1541 /*
1542 * RFC 1323 PAWS: If we have a timestamp reply on this segment
1543 * and it's less than ts_recent, drop it.
1544 */
1259 if (tp->t_state == TCPS_TIME_WAIT &&
1260 (ticks - tp->t_starttime) > tcp_msl) {
1261 rstreason = BANDLIM_UNLIMITED;
1262 goto dropwithreset;
1263 }
1264 if (CC_GT(to.to_cc, tp->cc_recv)) {
1265 tp = tcp_close(tp);
1266 goto findpcb;

--- 91 unchanged lines hidden (view full) ---

1358 }
1359 goto drop;
1360 }
1361
1362 /*
1363 * RFC 1323 PAWS: If we have a timestamp reply on this segment
1364 * and it's less than ts_recent, drop it.
1365 */
1545 if ((to.to_flag & TOF_TS) != 0 && tp->ts_recent &&
1366 if ((to.to_flags & TOF_TS) != 0 && tp->ts_recent &&
1546 TSTMP_LT(to.to_tsval, tp->ts_recent)) {
1547
1548 /* Check to see if ts_recent is over 24 days old. */
1549 if ((int)(ticks - tp->ts_recent_age) > TCP_PAWS_IDLE) {
1550 /*
1551 * Invalidate ts_recent. If this segment updates
1552 * ts_recent, the age will be reset later and ts_recent
1553 * will get a valid value. If it does not, setting

--- 15 unchanged lines hidden (view full) ---

1569
1570 /*
1571 * T/TCP mechanism
1572 * If T/TCP was negotiated and the segment doesn't have CC,
1573 * or if its CC is wrong then drop the segment.
1574 * RST segments do not have to comply with this.
1575 */
1576 if ((tp->t_flags & (TF_REQ_CC|TF_RCVD_CC)) == (TF_REQ_CC|TF_RCVD_CC) &&
1367 TSTMP_LT(to.to_tsval, tp->ts_recent)) {
1368
1369 /* Check to see if ts_recent is over 24 days old. */
1370 if ((int)(ticks - tp->ts_recent_age) > TCP_PAWS_IDLE) {
1371 /*
1372 * Invalidate ts_recent. If this segment updates
1373 * ts_recent, the age will be reset later and ts_recent
1374 * will get a valid value. If it does not, setting

--- 15 unchanged lines hidden (view full) ---

1390
1391 /*
1392 * T/TCP mechanism
1393 * If T/TCP was negotiated and the segment doesn't have CC,
1394 * or if its CC is wrong then drop the segment.
1395 * RST segments do not have to comply with this.
1396 */
1397 if ((tp->t_flags & (TF_REQ_CC|TF_RCVD_CC)) == (TF_REQ_CC|TF_RCVD_CC) &&
1577 ((to.to_flag & TOF_CC) == 0 || tp->cc_recv != to.to_cc))
1398 ((to.to_flags & TOF_CC) == 0 || tp->cc_recv != to.to_cc))
1578 goto dropafterack;
1579
1580 /*
1581 * In the SYN-RECEIVED state, validate that the packet belongs to
1582 * this connection before trimming the data to fit the receive
1583 * window. Check the sequence number versus IRS since we know
1584 * the sequence numbers haven't wrapped. This is a partial fix
1585 * for the "LAND" DoS attack.

--- 103 unchanged lines hidden (view full) ---

1689 }
1690
1691 /*
1692 * If last ACK falls within this segment's sequence numbers,
1693 * record its timestamp.
1694 * NOTE that the test is modified according to the latest
1695 * proposal of the tcplw@cray.com list (Braden 1993/04/26).
1696 */
1399 goto dropafterack;
1400
1401 /*
1402 * In the SYN-RECEIVED state, validate that the packet belongs to
1403 * this connection before trimming the data to fit the receive
1404 * window. Check the sequence number versus IRS since we know
1405 * the sequence numbers haven't wrapped. This is a partial fix
1406 * for the "LAND" DoS attack.

--- 103 unchanged lines hidden (view full) ---

1510 }
1511
1512 /*
1513 * If last ACK falls within this segment's sequence numbers,
1514 * record its timestamp.
1515 * NOTE that the test is modified according to the latest
1516 * proposal of the tcplw@cray.com list (Braden 1993/04/26).
1517 */
1697 if ((to.to_flag & TOF_TS) != 0 &&
1518 if ((to.to_flags & TOF_TS) != 0 &&
1698 SEQ_LEQ(th->th_seq, tp->last_ack_sent)) {
1699 tp->ts_recent_age = ticks;
1700 tp->ts_recent = to.to_tsval;
1701 }
1702
1703 /*
1704 * If a SYN is in the window, then this is an
1705 * error and we send an RST and drop the connection.

--- 37 unchanged lines hidden (view full) ---

1743 tp->snd_scale = tp->requested_s_scale;
1744 tp->rcv_scale = tp->request_r_scale;
1745 }
1746 /*
1747 * Upon successful completion of 3-way handshake,
1748 * update cache.CC if it was undefined, pass any queued
1749 * data to the user, and advance state appropriately.
1750 */
1519 SEQ_LEQ(th->th_seq, tp->last_ack_sent)) {
1520 tp->ts_recent_age = ticks;
1521 tp->ts_recent = to.to_tsval;
1522 }
1523
1524 /*
1525 * If a SYN is in the window, then this is an
1526 * error and we send an RST and drop the connection.

--- 37 unchanged lines hidden (view full) ---

1564 tp->snd_scale = tp->requested_s_scale;
1565 tp->rcv_scale = tp->request_r_scale;
1566 }
1567 /*
1568 * Upon successful completion of 3-way handshake,
1569 * update cache.CC if it was undefined, pass any queued
1570 * data to the user, and advance state appropriately.
1571 */
1751 if ((taop = tcp_gettaocache(inp)) != NULL &&
1572 if ((taop = tcp_gettaocache(&inp->inp_inc)) != NULL &&
1752 taop->tao_cc == 0)
1753 taop->tao_cc = tp->cc_recv;
1754
1755 /*
1756 * Make transitions:
1757 * SYN-RECEIVED -> ESTABLISHED
1758 * SYN-RECEIVED* -> FIN-WAIT-1
1759 */

--- 175 unchanged lines hidden (view full) ---

1935 * If we have a timestamp reply, update smoothed
1936 * round trip time. If no timestamp is present but
1937 * transmit timer is running and timed sequence
1938 * number was acked, update smoothed round trip time.
1939 * Since we now have an rtt measurement, cancel the
1940 * timer backoff (cf., Phil Karn's retransmit alg.).
1941 * Recompute the initial retransmit timer.
1942 */
1573 taop->tao_cc == 0)
1574 taop->tao_cc = tp->cc_recv;
1575
1576 /*
1577 * Make transitions:
1578 * SYN-RECEIVED -> ESTABLISHED
1579 * SYN-RECEIVED* -> FIN-WAIT-1
1580 */

--- 175 unchanged lines hidden (view full) ---

1756 * If we have a timestamp reply, update smoothed
1757 * round trip time. If no timestamp is present but
1758 * transmit timer is running and timed sequence
1759 * number was acked, update smoothed round trip time.
1760 * Since we now have an rtt measurement, cancel the
1761 * timer backoff (cf., Phil Karn's retransmit alg.).
1762 * Recompute the initial retransmit timer.
1763 */
1943 if (to.to_flag & TOF_TS)
1764 if (to.to_flags & TOF_TS)
1944 tcp_xmit_timer(tp, ticks - to.to_tsecr + 1);
1945 else if (tp->t_rtttime && SEQ_GT(th->th_ack, tp->t_rtseq))
1946 tcp_xmit_timer(tp, ticks - tp->t_rtttime);
1947
1948 /*
1949 * If all outstanding data is acked, stop retransmit
1950 * timer and remember to restart (more output or persist).
1951 * If there is more data to be acked, restart retransmit

--- 414 unchanged lines hidden (view full) ---

2366 TH_RST);
2367 else {
2368 if (thflags & TH_SYN)
2369 tlen++;
2370 /* mtod() below is safe as long as hdr dropping is delayed */
2371 tcp_respond(tp, mtod(m, void *), th, m, th->th_seq+tlen,
2372 (tcp_seq)0, TH_RST|TH_ACK);
2373 }
1765 tcp_xmit_timer(tp, ticks - to.to_tsecr + 1);
1766 else if (tp->t_rtttime && SEQ_GT(th->th_ack, tp->t_rtseq))
1767 tcp_xmit_timer(tp, ticks - tp->t_rtttime);
1768
1769 /*
1770 * If all outstanding data is acked, stop retransmit
1771 * timer and remember to restart (more output or persist).
1772 * If there is more data to be acked, restart retransmit

--- 414 unchanged lines hidden (view full) ---

2187 TH_RST);
2188 else {
2189 if (thflags & TH_SYN)
2190 tlen++;
2191 /* mtod() below is safe as long as hdr dropping is delayed */
2192 tcp_respond(tp, mtod(m, void *), th, m, th->th_seq+tlen,
2193 (tcp_seq)0, TH_RST|TH_ACK);
2194 }
2374 /* destroy temporarily created socket */
2375 if (dropsocket)
2376 (void) soabort(so);
2377 return;
2378
2379drop:
2380 /*
2381 * Drop space held by incoming segment and return.
2382 */
2383#ifdef TCPDEBUG
2384 if (tp == 0 || (tp->t_inpcb->inp_socket->so_options & SO_DEBUG))
2385 tcp_trace(TA_DROP, ostate, tp, (void *)tcp_saveipgen,
2386 &tcp_savetcp, 0);
2387#endif
2388 m_freem(m);
2195 return;
2196
2197drop:
2198 /*
2199 * Drop space held by incoming segment and return.
2200 */
2201#ifdef TCPDEBUG
2202 if (tp == 0 || (tp->t_inpcb->inp_socket->so_options & SO_DEBUG))
2203 tcp_trace(TA_DROP, ostate, tp, (void *)tcp_saveipgen,
2204 &tcp_savetcp, 0);
2205#endif
2206 m_freem(m);
2389 /* destroy temporarily created socket */
2390 if (dropsocket)
2391 (void) soabort(so);
2392 return;
2393}
2394
2207 return;
2208}
2209
2210/*
2211 * Parse TCP options and place in tcpopt.
2212 */
2395static void
2213static void
2396tcp_dooptions(tp, cp, cnt, th, to)
2397 struct tcpcb *tp;
2214tcp_dooptions(to, cp, cnt, is_syn)
2215 struct tcpopt *to;
2398 u_char *cp;
2399 int cnt;
2216 u_char *cp;
2217 int cnt;
2400 struct tcphdr *th;
2401 struct tcpopt *to;
2402{
2218{
2403 u_short mss = 0;
2404 int opt, optlen;
2405
2219 int opt, optlen;
2220
2221 to->to_flags = 0;
2406 for (; cnt > 0; cnt -= optlen, cp += optlen) {
2407 opt = cp[0];
2408 if (opt == TCPOPT_EOL)
2409 break;
2410 if (opt == TCPOPT_NOP)
2411 optlen = 1;
2412 else {
2413 if (cnt < 2)
2414 break;
2415 optlen = cp[1];
2416 if (optlen < 2 || optlen > cnt)
2417 break;
2418 }
2419 switch (opt) {
2222 for (; cnt > 0; cnt -= optlen, cp += optlen) {
2223 opt = cp[0];
2224 if (opt == TCPOPT_EOL)
2225 break;
2226 if (opt == TCPOPT_NOP)
2227 optlen = 1;
2228 else {
2229 if (cnt < 2)
2230 break;
2231 optlen = cp[1];
2232 if (optlen < 2 || optlen > cnt)
2233 break;
2234 }
2235 switch (opt) {
2420
2421 default:
2422 continue;
2423
2424 case TCPOPT_MAXSEG:
2425 if (optlen != TCPOLEN_MAXSEG)
2426 continue;
2236 case TCPOPT_MAXSEG:
2237 if (optlen != TCPOLEN_MAXSEG)
2238 continue;
2427 if (!(th->th_flags & TH_SYN))
2239 if (!is_syn)
2428 continue;
2240 continue;
2429 bcopy((char *) cp + 2, (char *) &mss, sizeof(mss));
2430 NTOHS(mss);
2241 to->to_flags |= TOF_MSS;
2242 bcopy((char *)cp + 2,
2243 (char *)&to->to_mss, sizeof(to->to_mss));
2244 NTOHS(to->to_mss);
2431 break;
2245 break;
2432
2433 case TCPOPT_WINDOW:
2434 if (optlen != TCPOLEN_WINDOW)
2435 continue;
2246 case TCPOPT_WINDOW:
2247 if (optlen != TCPOLEN_WINDOW)
2248 continue;
2436 if (!(th->th_flags & TH_SYN))
2249 if (! is_syn)
2437 continue;
2250 continue;
2438 tp->t_flags |= TF_RCVD_SCALE;
2439 tp->requested_s_scale = min(cp[2], TCP_MAX_WINSHIFT);
2251 to->to_flags |= TOF_SCALE;
2252 to->to_requested_s_scale = min(cp[2], TCP_MAX_WINSHIFT);
2440 break;
2253 break;
2441
2442 case TCPOPT_TIMESTAMP:
2443 if (optlen != TCPOLEN_TIMESTAMP)
2444 continue;
2254 case TCPOPT_TIMESTAMP:
2255 if (optlen != TCPOLEN_TIMESTAMP)
2256 continue;
2445 to->to_flag |= TOF_TS;
2257 to->to_flags |= TOF_TS;
2446 bcopy((char *)cp + 2,
2447 (char *)&to->to_tsval, sizeof(to->to_tsval));
2448 NTOHL(to->to_tsval);
2449 bcopy((char *)cp + 6,
2450 (char *)&to->to_tsecr, sizeof(to->to_tsecr));
2451 NTOHL(to->to_tsecr);
2258 bcopy((char *)cp + 2,
2259 (char *)&to->to_tsval, sizeof(to->to_tsval));
2260 NTOHL(to->to_tsval);
2261 bcopy((char *)cp + 6,
2262 (char *)&to->to_tsecr, sizeof(to->to_tsecr));
2263 NTOHL(to->to_tsecr);
2452
2453 /*
2454 * A timestamp received in a SYN makes
2455 * it ok to send timestamp requests and replies.
2456 */
2457 if (th->th_flags & TH_SYN) {
2458 tp->t_flags |= TF_RCVD_TSTMP;
2459 tp->ts_recent = to->to_tsval;
2460 tp->ts_recent_age = ticks;
2461 }
2462 break;
2463 case TCPOPT_CC:
2464 if (optlen != TCPOLEN_CC)
2465 continue;
2264 break;
2265 case TCPOPT_CC:
2266 if (optlen != TCPOLEN_CC)
2267 continue;
2466 to->to_flag |= TOF_CC;
2268 to->to_flags |= TOF_CC;
2467 bcopy((char *)cp + 2,
2468 (char *)&to->to_cc, sizeof(to->to_cc));
2469 NTOHL(to->to_cc);
2269 bcopy((char *)cp + 2,
2270 (char *)&to->to_cc, sizeof(to->to_cc));
2271 NTOHL(to->to_cc);
2470 /*
2471 * A CC or CC.new option received in a SYN makes
2472 * it ok to send CC in subsequent segments.
2473 */
2474 if (th->th_flags & TH_SYN)
2475 tp->t_flags |= TF_RCVD_CC;
2476 break;
2477 case TCPOPT_CCNEW:
2478 if (optlen != TCPOLEN_CC)
2479 continue;
2272 break;
2273 case TCPOPT_CCNEW:
2274 if (optlen != TCPOLEN_CC)
2275 continue;
2480 if (!(th->th_flags & TH_SYN))
2276 if (!is_syn)
2481 continue;
2277 continue;
2482 to->to_flag |= TOF_CCNEW;
2278 to->to_flags |= TOF_CCNEW;
2483 bcopy((char *)cp + 2,
2484 (char *)&to->to_cc, sizeof(to->to_cc));
2485 NTOHL(to->to_cc);
2279 bcopy((char *)cp + 2,
2280 (char *)&to->to_cc, sizeof(to->to_cc));
2281 NTOHL(to->to_cc);
2486 /*
2487 * A CC or CC.new option received in a SYN makes
2488 * it ok to send CC in subsequent segments.
2489 */
2490 tp->t_flags |= TF_RCVD_CC;
2491 break;
2492 case TCPOPT_CCECHO:
2493 if (optlen != TCPOLEN_CC)
2494 continue;
2282 break;
2283 case TCPOPT_CCECHO:
2284 if (optlen != TCPOLEN_CC)
2285 continue;
2495 if (!(th->th_flags & TH_SYN))
2286 if (!is_syn)
2496 continue;
2287 continue;
2497 to->to_flag |= TOF_CCECHO;
2288 to->to_flags |= TOF_CCECHO;
2498 bcopy((char *)cp + 2,
2499 (char *)&to->to_ccecho, sizeof(to->to_ccecho));
2500 NTOHL(to->to_ccecho);
2501 break;
2289 bcopy((char *)cp + 2,
2290 (char *)&to->to_ccecho, sizeof(to->to_ccecho));
2291 NTOHL(to->to_ccecho);
2292 break;
2293 default:
2294 continue;
2502 }
2503 }
2295 }
2296 }
2504 if (th->th_flags & TH_SYN)
2505 tcp_mss(tp, mss); /* sets t_maxseg */
2506}
2507
2508/*
2509 * Pull out of band byte out of a segment so
2510 * it doesn't appear in the user's data queue.
2511 * It is still reflected in the segment length for
2512 * sequencing purposes.
2513 */

--- 156 unchanged lines hidden (view full) ---

2670 isipv6 = ((inp->inp_vflag & INP_IPV6) != 0) ? 1 : 0;
2671 min_protoh = isipv6 ? sizeof (struct ip6_hdr) + sizeof (struct tcphdr)
2672 : sizeof (struct tcpiphdr);
2673#else
2674#define min_protoh (sizeof (struct tcpiphdr))
2675#endif
2676#ifdef INET6
2677 if (isipv6)
2297}
2298
2299/*
2300 * Pull out of band byte out of a segment so
2301 * it doesn't appear in the user's data queue.
2302 * It is still reflected in the segment length for
2303 * sequencing purposes.
2304 */

--- 156 unchanged lines hidden (view full) ---

2461 isipv6 = ((inp->inp_vflag & INP_IPV6) != 0) ? 1 : 0;
2462 min_protoh = isipv6 ? sizeof (struct ip6_hdr) + sizeof (struct tcphdr)
2463 : sizeof (struct tcpiphdr);
2464#else
2465#define min_protoh (sizeof (struct tcpiphdr))
2466#endif
2467#ifdef INET6
2468 if (isipv6)
2678 rt = tcp_rtlookup6(inp);
2469 rt = tcp_rtlookup6(&inp->inp_inc);
2679 else
2680#endif
2470 else
2471#endif
2681 rt = tcp_rtlookup(inp);
2472 rt = tcp_rtlookup(&inp->inp_inc);
2682 if (rt == NULL) {
2683 tp->t_maxopd = tp->t_maxseg =
2684#ifdef INET6
2685 isipv6 ? tcp_v6mssdflt :
2686#endif /* INET6 */
2687 tcp_mssdflt;
2688 return;
2689 }

--- 189 unchanged lines hidden (view full) ---

2879 isipv6 = ((tp->t_inpcb->inp_vflag & INP_IPV6) != 0) ? 1 : 0;
2880 min_protoh = isipv6 ? sizeof (struct ip6_hdr) + sizeof (struct tcphdr)
2881 : sizeof (struct tcpiphdr);
2882#else
2883#define min_protoh (sizeof (struct tcpiphdr))
2884#endif
2885#ifdef INET6
2886 if (isipv6)
2473 if (rt == NULL) {
2474 tp->t_maxopd = tp->t_maxseg =
2475#ifdef INET6
2476 isipv6 ? tcp_v6mssdflt :
2477#endif /* INET6 */
2478 tcp_mssdflt;
2479 return;
2480 }

--- 189 unchanged lines hidden (view full) ---

2670 isipv6 = ((tp->t_inpcb->inp_vflag & INP_IPV6) != 0) ? 1 : 0;
2671 min_protoh = isipv6 ? sizeof (struct ip6_hdr) + sizeof (struct tcphdr)
2672 : sizeof (struct tcpiphdr);
2673#else
2674#define min_protoh (sizeof (struct tcpiphdr))
2675#endif
2676#ifdef INET6
2677 if (isipv6)
2887 rt = tcp_rtlookup6(tp->t_inpcb);
2678 rt = tcp_rtlookup6(&tp->t_inpcb->inp_inc);
2888 else
2889#endif /* INET6 */
2679 else
2680#endif /* INET6 */
2890 rt = tcp_rtlookup(tp->t_inpcb);
2681 rt = tcp_rtlookup(&tp->t_inpcb->inp_inc);
2891 if (rt == NULL)
2892 return
2893#ifdef INET6
2894 isipv6 ? tcp_v6mssdflt :
2895#endif /* INET6 */
2896 tcp_mssdflt;
2897
2898 return rt->rt_ifp->if_mtu - min_protoh;

--- 40 unchanged lines hidden --- 		2682 if (rt == NULL)
2683 return
2684#ifdef INET6
2685 isipv6 ? tcp_v6mssdflt :
2686#endif /* INET6 */
2687 tcp_mssdflt;
2688
2689 return rt->rt_ifp->if_mtu - min_protoh;

--- 40 unchanged lines hidden ---