633 lines
20 KiB
C
633 lines
20 KiB
C
/*-
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* Copyright (c) 1982, 1986, 1988, 1990, 1993, 1994, 1995
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* The Regents of the University of California. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @(#)tcp_sack.c 8.12 (Berkeley) 5/24/95
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* $FreeBSD$
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*/
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/*-
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* Copyright (c) 1982, 1986, 1988, 1990, 1993, 1994
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* The Regents of the University of California. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @@(#)COPYRIGHT 1.1 (NRL) 17 January 1995
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*
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* NRL grants permission for redistribution and use in source and binary
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* forms, with or without modification, of the software and documentation
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* created at NRL provided that the following conditions are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgements:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* This product includes software developed at the Information
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* Technology Division, US Naval Research Laboratory.
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* 4. Neither the name of the NRL nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THE SOFTWARE PROVIDED BY NRL IS PROVIDED BY NRL AND CONTRIBUTORS ``AS
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* IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
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* PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL NRL OR
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* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
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* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* The views and conclusions contained in the software and documentation
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* are those of the authors and should not be interpreted as representing
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* official policies, either expressed or implied, of the US Naval
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* Research Laboratory (NRL).
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*/
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#include "opt_inet.h"
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#include "opt_inet6.h"
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#include "opt_ipsec.h"
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#include "opt_tcpdebug.h"
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#include "opt_tcp_input.h"
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#include "opt_tcp_sack.h"
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/kernel.h>
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#include <sys/sysctl.h>
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#include <sys/malloc.h>
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#include <sys/mbuf.h>
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#include <sys/proc.h> /* for proc0 declaration */
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#include <sys/protosw.h>
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#include <sys/socket.h>
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#include <sys/socketvar.h>
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#include <sys/syslog.h>
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#include <sys/systm.h>
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#include <machine/cpu.h> /* before tcp_seq.h, for tcp_random18() */
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#include <vm/uma.h>
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#include <net/if.h>
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#include <net/route.h>
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#include <netinet/in.h>
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#include <netinet/in_systm.h>
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#include <netinet/ip.h>
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#include <netinet/ip_icmp.h> /* for ICMP_BANDLIM */
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#include <netinet/in_var.h>
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#include <netinet/icmp_var.h> /* for ICMP_BANDLIM */
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#include <netinet/in_pcb.h>
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#include <netinet/ip_var.h>
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#include <netinet/ip6.h>
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#include <netinet/icmp6.h>
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#include <netinet6/nd6.h>
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#include <netinet6/ip6_var.h>
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#include <netinet6/in6_pcb.h>
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#include <netinet/tcp.h>
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#include <netinet/tcp_fsm.h>
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#include <netinet/tcp_seq.h>
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#include <netinet/tcp_timer.h>
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#include <netinet/tcp_var.h>
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#include <netinet6/tcp6_var.h>
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#include <netinet/tcpip.h>
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#ifdef TCPDEBUG
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#include <netinet/tcp_debug.h>
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#endif /* TCPDEBUG */
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#ifdef FAST_IPSEC
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#include <netipsec/ipsec.h>
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#include <netipsec/ipsec6.h>
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#endif
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#ifdef IPSEC
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#include <netinet6/ipsec.h>
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#include <netinet6/ipsec6.h>
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#include <netkey/key.h>
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#endif /*IPSEC*/
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#include <machine/in_cksum.h>
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extern struct uma_zone *sack_hole_zone;
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SYSCTL_NODE(_net_inet_tcp, OID_AUTO, sack, CTLFLAG_RW, 0, "TCP SACK");
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int tcp_do_sack = 1;
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SYSCTL_INT(_net_inet_tcp_sack, OID_AUTO, enable, CTLFLAG_RW,
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&tcp_do_sack, 0, "Enable/Disable TCP SACK support");
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TUNABLE_INT("net.inet.tcp.sack.enable", &tcp_do_sack);
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static int tcp_sack_maxholes = 128;
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SYSCTL_INT(_net_inet_tcp_sack, OID_AUTO, maxholes, CTLFLAG_RW,
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&tcp_sack_maxholes, 0,
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"Maximum number of TCP SACK holes allowed per connection");
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static int tcp_sack_globalmaxholes = 65536;
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SYSCTL_INT(_net_inet_tcp_sack, OID_AUTO, globalmaxholes, CTLFLAG_RW,
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&tcp_sack_globalmaxholes, 0,
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"Global maximum number of TCP SACK holes");
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static int tcp_sack_globalholes = 0;
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SYSCTL_INT(_net_inet_tcp_sack, OID_AUTO, globalholes, CTLFLAG_RD,
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&tcp_sack_globalholes, 0,
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"Global number of TCP SACK holes currently allocated");
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/*
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* This function is called upon receipt of new valid data (while not in header
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* prediction mode), and it updates the ordered list of sacks.
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*/
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void
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tcp_update_sack_list(tp, rcv_laststart, rcv_lastend)
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struct tcpcb *tp;
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tcp_seq rcv_laststart, rcv_lastend;
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{
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/*
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* First reported block MUST be the most recent one. Subsequent
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* blocks SHOULD be in the order in which they arrived at the
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* receiver. These two conditions make the implementation fully
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* compliant with RFC 2018.
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*/
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int i, j = 0, count = 0, lastpos = -1;
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struct sackblk sack, firstsack, temp[MAX_SACK_BLKS];
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INP_LOCK_ASSERT(tp->t_inpcb);
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/* First clean up current list of sacks */
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for (i = 0; i < tp->rcv_numsacks; i++) {
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sack = tp->sackblks[i];
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if (sack.start == 0 && sack.end == 0) {
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count++; /* count = number of blocks to be discarded */
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continue;
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}
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if (SEQ_LEQ(sack.end, tp->rcv_nxt)) {
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tp->sackblks[i].start = tp->sackblks[i].end = 0;
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count++;
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} else {
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temp[j].start = tp->sackblks[i].start;
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temp[j++].end = tp->sackblks[i].end;
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}
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}
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tp->rcv_numsacks -= count;
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if (tp->rcv_numsacks == 0) { /* no sack blocks currently (fast path) */
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tcp_clean_sackreport(tp);
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if (SEQ_LT(tp->rcv_nxt, rcv_laststart)) {
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/* ==> need first sack block */
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tp->sackblks[0].start = rcv_laststart;
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tp->sackblks[0].end = rcv_lastend;
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tp->rcv_numsacks = 1;
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}
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return;
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}
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/* Otherwise, sack blocks are already present. */
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for (i = 0; i < tp->rcv_numsacks; i++)
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tp->sackblks[i] = temp[i]; /* first copy back sack list */
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if (SEQ_GEQ(tp->rcv_nxt, rcv_lastend))
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return; /* sack list remains unchanged */
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/*
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* From here, segment just received should be (part of) the 1st sack.
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* Go through list, possibly coalescing sack block entries.
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*/
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firstsack.start = rcv_laststart;
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firstsack.end = rcv_lastend;
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for (i = 0; i < tp->rcv_numsacks; i++) {
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sack = tp->sackblks[i];
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if (SEQ_LT(sack.end, firstsack.start) ||
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SEQ_GT(sack.start, firstsack.end))
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continue; /* no overlap */
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if (sack.start == firstsack.start && sack.end == firstsack.end){
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/*
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* identical block; delete it here since we will
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* move it to the front of the list.
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*/
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tp->sackblks[i].start = tp->sackblks[i].end = 0;
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lastpos = i; /* last posn with a zero entry */
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continue;
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}
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if (SEQ_LEQ(sack.start, firstsack.start))
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firstsack.start = sack.start; /* merge blocks */
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if (SEQ_GEQ(sack.end, firstsack.end))
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firstsack.end = sack.end; /* merge blocks */
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tp->sackblks[i].start = tp->sackblks[i].end = 0;
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lastpos = i; /* last posn with a zero entry */
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}
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if (lastpos != -1) { /* at least one merge */
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for (i = 0, j = 1; i < tp->rcv_numsacks; i++) {
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sack = tp->sackblks[i];
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if (sack.start == 0 && sack.end == 0)
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continue;
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temp[j++] = sack;
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}
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tp->rcv_numsacks = j; /* including first blk (added later) */
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for (i = 1; i < tp->rcv_numsacks; i++) /* now copy back */
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tp->sackblks[i] = temp[i];
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} else { /* no merges -- shift sacks by 1 */
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if (tp->rcv_numsacks < MAX_SACK_BLKS)
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tp->rcv_numsacks++;
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for (i = tp->rcv_numsacks-1; i > 0; i--)
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tp->sackblks[i] = tp->sackblks[i-1];
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}
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tp->sackblks[0] = firstsack;
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return;
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}
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/*
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* Delete all receiver-side SACK information.
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*/
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void
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tcp_clean_sackreport(tp)
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struct tcpcb *tp;
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{
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int i;
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INP_LOCK_ASSERT(tp->t_inpcb);
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tp->rcv_numsacks = 0;
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for (i = 0; i < MAX_SACK_BLKS; i++)
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tp->sackblks[i].start = tp->sackblks[i].end=0;
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}
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/*
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* Process the TCP SACK option. Returns 1 if tcp_dooptions() should continue,
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* and 0 otherwise, if the option was fine. tp->snd_holes is an ordered list
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* of holes (oldest to newest, in terms of the sequence space).
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*/
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int
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tcp_sack_option(struct tcpcb *tp, struct tcphdr *th, u_char *cp, int optlen)
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{
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int tmp_olen;
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u_char *tmp_cp;
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struct sackhole *cur, *p, *temp;
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INP_LOCK_ASSERT(tp->t_inpcb);
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if (!tp->sack_enable)
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return (1);
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if ((th->th_flags & TH_ACK) == 0)
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return (1);
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/* Note: TCPOLEN_SACK must be 2*sizeof(tcp_seq) */
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if (optlen <= 2 || (optlen - 2) % TCPOLEN_SACK != 0)
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return (1);
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/* If ack is outside [snd_una, snd_max], ignore the SACK options */
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if (SEQ_LT(th->th_ack, tp->snd_una) || SEQ_GT(th->th_ack, tp->snd_max))
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return (1);
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tmp_cp = cp + 2;
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tmp_olen = optlen - 2;
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tcpstat.tcps_sack_rcv_blocks++;
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if (tp->snd_numholes < 0) /* XXX panic? */
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tp->snd_numholes = 0;
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if (tp->t_maxseg == 0)
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panic("tcp_sack_option"); /* Should never happen */
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while (tmp_olen > 0) {
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struct sackblk sack;
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bcopy(tmp_cp, (char *) &(sack.start), sizeof(tcp_seq));
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sack.start = ntohl(sack.start);
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bcopy(tmp_cp + sizeof(tcp_seq),
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(char *) &(sack.end), sizeof(tcp_seq));
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sack.end = ntohl(sack.end);
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tmp_olen -= TCPOLEN_SACK;
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tmp_cp += TCPOLEN_SACK;
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if (SEQ_LEQ(sack.end, sack.start))
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continue; /* bad SACK fields */
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if (SEQ_LEQ(sack.end, tp->snd_una))
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continue; /* old block */
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if (SEQ_GT(th->th_ack, tp->snd_una)) {
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if (SEQ_LT(sack.start, th->th_ack))
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continue;
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}
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if (SEQ_GT(sack.end, tp->snd_max))
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continue;
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if (tp->snd_holes == NULL) { /* first hole */
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if (tcp_sack_globalholes >= tcp_sack_globalmaxholes ||
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tcp_sack_maxholes == 0) {
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tcpstat.tcps_sack_sboverflow++;
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continue;
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}
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tp->snd_holes = (struct sackhole *)
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uma_zalloc(sack_hole_zone,M_NOWAIT);
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if (tp->snd_holes == NULL) {
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/* ENOBUFS, so ignore SACKed block for now*/
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continue;
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}
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cur = tp->snd_holes;
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cur->start = th->th_ack;
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cur->end = sack.start;
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cur->rxmit = cur->start;
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cur->next = NULL;
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tp->snd_numholes = 1;
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tcp_sack_globalholes++;
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tp->rcv_lastsack = sack.end;
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continue; /* with next sack block */
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}
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/* Go thru list of holes: p = previous, cur = current */
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p = cur = tp->snd_holes;
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while (cur) {
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if (SEQ_LEQ(sack.end, cur->start))
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/* SACKs data before the current hole */
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break; /* no use going through more holes */
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if (SEQ_GEQ(sack.start, cur->end)) {
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/* SACKs data beyond the current hole */
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p = cur;
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cur = cur->next;
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continue;
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}
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if (SEQ_LEQ(sack.start, cur->start)) {
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/* Data acks at least the beginning of hole */
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if (SEQ_GEQ(sack.end, cur->end)) {
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/* Acks entire hole, so delete hole */
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if (p != cur) {
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p->next = cur->next;
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uma_zfree(sack_hole_zone, cur);
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cur = p->next;
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} else {
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cur = cur->next;
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uma_zfree(sack_hole_zone, p);
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p = cur;
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tp->snd_holes = p;
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}
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tp->snd_numholes--;
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tcp_sack_globalholes--;
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continue;
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}
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/* otherwise, move start of hole forward */
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cur->start = sack.end;
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cur->rxmit = SEQ_MAX(cur->rxmit, cur->start);
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p = cur;
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cur = cur->next;
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continue;
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}
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/* move end of hole backward */
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if (SEQ_GEQ(sack.end, cur->end)) {
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cur->end = sack.start;
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cur->rxmit = SEQ_MIN(cur->rxmit, cur->end);
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p = cur;
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cur = cur->next;
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continue;
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}
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if (SEQ_LT(cur->start, sack.start) &&
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SEQ_GT(cur->end, sack.end)) {
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/*
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* ACKs some data in middle of a hole; need to
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* split current hole
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*/
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if (tp->snd_numholes >= tcp_sack_maxholes ||
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tcp_sack_globalholes >=
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tcp_sack_globalmaxholes) {
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tcpstat.tcps_sack_sboverflow++;
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continue;
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}
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temp = (struct sackhole *)
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uma_zalloc(sack_hole_zone,M_NOWAIT);
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if (temp == NULL)
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continue; /* ENOBUFS */
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temp->next = cur->next;
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temp->start = sack.end;
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temp->end = cur->end;
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temp->rxmit = SEQ_MAX(cur->rxmit, temp->start);
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cur->end = sack.start;
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cur->rxmit = SEQ_MIN(cur->rxmit, cur->end);
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cur->next = temp;
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p = temp;
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cur = p->next;
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tp->snd_numholes++;
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tcp_sack_globalholes++;
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}
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}
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/* At this point, p points to the last hole on the list */
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if (SEQ_LT(tp->rcv_lastsack, sack.start)) {
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/*
|
|
* Need to append new hole at end.
|
|
* Last hole is p (and it's not NULL).
|
|
*/
|
|
if (tp->snd_numholes >= tcp_sack_maxholes ||
|
|
tcp_sack_globalholes >= tcp_sack_globalmaxholes) {
|
|
tcpstat.tcps_sack_sboverflow++;
|
|
continue;
|
|
}
|
|
temp = (struct sackhole *)
|
|
uma_zalloc(sack_hole_zone,M_NOWAIT);
|
|
if (temp == NULL)
|
|
continue; /* ENOBUFS */
|
|
temp->start = tp->rcv_lastsack;
|
|
temp->end = sack.start;
|
|
temp->rxmit = temp->start;
|
|
temp->next = 0;
|
|
p->next = temp;
|
|
tp->rcv_lastsack = sack.end;
|
|
tp->snd_numholes++;
|
|
tcp_sack_globalholes++;
|
|
}
|
|
}
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* Delete stale (i.e, cumulatively ack'd) holes. Hole is deleted only if
|
|
* it is completely acked; otherwise, tcp_sack_option(), called from
|
|
* tcp_dooptions(), will fix up the hole.
|
|
*/
|
|
void
|
|
tcp_del_sackholes(tp, th)
|
|
struct tcpcb *tp;
|
|
struct tcphdr *th;
|
|
{
|
|
INP_LOCK_ASSERT(tp->t_inpcb);
|
|
if (tp->sack_enable && tp->t_state != TCPS_LISTEN) {
|
|
/* max because this could be an older ack just arrived */
|
|
tcp_seq lastack = SEQ_GT(th->th_ack, tp->snd_una) ?
|
|
th->th_ack : tp->snd_una;
|
|
struct sackhole *cur = tp->snd_holes;
|
|
struct sackhole *prev;
|
|
while (cur)
|
|
if (SEQ_LEQ(cur->end, lastack)) {
|
|
prev = cur;
|
|
cur = cur->next;
|
|
uma_zfree(sack_hole_zone, prev);
|
|
tp->snd_numholes--;
|
|
tcp_sack_globalholes--;
|
|
} else if (SEQ_LT(cur->start, lastack)) {
|
|
cur->start = lastack;
|
|
if (SEQ_LT(cur->rxmit, cur->start))
|
|
cur->rxmit = cur->start;
|
|
break;
|
|
} else
|
|
break;
|
|
tp->snd_holes = cur;
|
|
}
|
|
}
|
|
|
|
void
|
|
tcp_free_sackholes(struct tcpcb *tp)
|
|
{
|
|
struct sackhole *p, *q;
|
|
|
|
INP_LOCK_ASSERT(tp->t_inpcb);
|
|
q = tp->snd_holes;
|
|
while (q != NULL) {
|
|
p = q;
|
|
q = q->next;
|
|
uma_zfree(sack_hole_zone, p);
|
|
tcp_sack_globalholes--;
|
|
}
|
|
tp->snd_holes = 0;
|
|
tp->snd_numholes = 0;
|
|
}
|
|
|
|
/*
|
|
* Partial ack handling within a sack recovery episode.
|
|
* Keeping this very simple for now. When a partial ack
|
|
* is received, force snd_cwnd to a value that will allow
|
|
* the sender to transmit no more than 2 segments.
|
|
* If necessary, a better scheme can be adopted at a
|
|
* later point, but for now, the goal is to prevent the
|
|
* sender from bursting a large amount of data in the midst
|
|
* of sack recovery.
|
|
*/
|
|
void
|
|
tcp_sack_partialack(tp, th)
|
|
struct tcpcb *tp;
|
|
struct tcphdr *th;
|
|
{
|
|
INP_LOCK_ASSERT(tp->t_inpcb);
|
|
int num_segs = 1;
|
|
int sack_bytes_rxmt = 0;
|
|
|
|
callout_stop(tp->tt_rexmt);
|
|
tp->t_rtttime = 0;
|
|
/* send one or 2 segments based on how much new data was acked */
|
|
if (((th->th_ack - tp->snd_una) / tp->t_maxseg) > 2)
|
|
num_segs = 2;
|
|
(void)tcp_sack_output(tp, &sack_bytes_rxmt);
|
|
tp->snd_cwnd = sack_bytes_rxmt + (tp->snd_nxt - tp->sack_newdata) +
|
|
num_segs * tp->t_maxseg;
|
|
tp->t_flags |= TF_ACKNOW;
|
|
(void) tcp_output(tp);
|
|
}
|
|
|
|
#ifdef TCP_SACK_DEBUG
|
|
void
|
|
tcp_print_holes(struct tcpcb *tp)
|
|
{
|
|
struct sackhole *p = tp->snd_holes;
|
|
if (p == 0)
|
|
return;
|
|
printf("Hole report: start--end dups rxmit\n");
|
|
while (p) {
|
|
printf("%x--%x r %x\n", p->start, p->end, p->rxmit);
|
|
p = p->next;
|
|
}
|
|
printf("\n");
|
|
}
|
|
#endif /* TCP_SACK_DEBUG */
|
|
|
|
/*
|
|
* Returns pointer to a sackhole if there are any pending retransmissions;
|
|
* NULL otherwise.
|
|
*/
|
|
struct sackhole *
|
|
tcp_sack_output(struct tcpcb *tp, int *sack_bytes_rexmt)
|
|
{
|
|
struct sackhole *p = NULL;
|
|
|
|
INP_LOCK_ASSERT(tp->t_inpcb);
|
|
if (!tp->sack_enable)
|
|
return (NULL);
|
|
*sack_bytes_rexmt = 0;
|
|
for (p = tp->snd_holes; p ; p = p->next) {
|
|
if (SEQ_LT(p->rxmit, p->end)) {
|
|
if (SEQ_LT(p->rxmit, tp->snd_una)) {/* old SACK hole */
|
|
continue;
|
|
}
|
|
#ifdef TCP_SACK_DEBUG
|
|
if (p)
|
|
tcp_print_holes(tp);
|
|
#endif
|
|
*sack_bytes_rexmt += (p->rxmit - p->start);
|
|
break;
|
|
}
|
|
*sack_bytes_rexmt += (p->rxmit - p->start);
|
|
}
|
|
return (p);
|
|
}
|
|
|
|
/*
|
|
* After a timeout, the SACK list may be rebuilt. This SACK information
|
|
* should be used to avoid retransmitting SACKed data. This function
|
|
* traverses the SACK list to see if snd_nxt should be moved forward.
|
|
*/
|
|
void
|
|
tcp_sack_adjust(struct tcpcb *tp)
|
|
{
|
|
INP_LOCK_ASSERT(tp->t_inpcb);
|
|
struct sackhole *cur = tp->snd_holes;
|
|
if (cur == NULL)
|
|
return; /* No holes */
|
|
if (SEQ_GEQ(tp->snd_nxt, tp->rcv_lastsack))
|
|
return; /* We're already beyond any SACKed blocks */
|
|
/*
|
|
* Two cases for which we want to advance snd_nxt:
|
|
* i) snd_nxt lies between end of one hole and beginning of another
|
|
* ii) snd_nxt lies between end of last hole and rcv_lastsack
|
|
*/
|
|
while (cur->next) {
|
|
if (SEQ_LT(tp->snd_nxt, cur->end))
|
|
return;
|
|
if (SEQ_GEQ(tp->snd_nxt, cur->next->start))
|
|
cur = cur->next;
|
|
else {
|
|
tp->snd_nxt = cur->next->start;
|
|
return;
|
|
}
|
|
}
|
|
if (SEQ_LT(tp->snd_nxt, cur->end))
|
|
return;
|
|
tp->snd_nxt = tp->rcv_lastsack;
|
|
return;
|
|
}
|