a6b350eb35
Discussed with: glebius
2460 lines
72 KiB
C
2460 lines
72 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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* Copyright (c) 2007-2008,2010
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* Swinburne University of Technology, Melbourne, Australia.
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* Copyright (c) 2009-2010 Lawrence Stewart <lstewart@freebsd.org>
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* Copyright (c) 2010 The FreeBSD Foundation
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* Copyright (c) 2010-2011 Juniper Networks, Inc.
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* Copyright (c) 2015 Netflix Inc.
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* All rights reserved.
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*
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* Portions of this software were developed at the Centre for Advanced Internet
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* Architectures, Swinburne University of Technology, by Lawrence Stewart,
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* James Healy and David Hayes, made possible in part by a grant from the Cisco
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* University Research Program Fund at Community Foundation Silicon Valley.
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*
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* Portions of this software were developed at the Centre for Advanced
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* Internet Architectures, Swinburne University of Technology, Melbourne,
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* Australia by David Hayes under sponsorship from the FreeBSD Foundation.
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*
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* Portions of this software were developed by Robert N. M. Watson under
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* contract to Juniper Networks, Inc.
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*
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* Portions of this software were developed by Randall R. Stewart while
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* working for Netflix Inc.
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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_input.c 8.12 (Berkeley) 5/24/95
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include "opt_ipfw.h" /* for ipfw_fwd */
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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_kdtrace.h"
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#include "opt_tcpdebug.h"
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#include <sys/param.h>
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#include <sys/module.h>
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#include <sys/kernel.h>
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#include <sys/hhook.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/sdt.h>
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#include <sys/signalvar.h>
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#include <sys/socket.h>
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#include <sys/socketvar.h>
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#include <sys/sysctl.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/if_var.h>
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#include <net/route.h>
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#include <net/vnet.h>
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#define TCPSTATES /* for logging */
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#include <netinet/cc.h>
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#include <netinet/in.h>
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#include <netinet/in_kdtrace.h>
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#include <netinet/in_pcb.h>
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#include <netinet/in_systm.h>
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#include <netinet/in_var.h>
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#include <netinet/ip.h>
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#include <netinet/ip_icmp.h> /* required for icmp_var.h */
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#include <netinet/icmp_var.h> /* for ICMP_BANDLIM */
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#include <netinet/ip_var.h>
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#include <netinet/ip_options.h>
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#include <netinet/ip6.h>
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#include <netinet/icmp6.h>
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#include <netinet6/in6_pcb.h>
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#include <netinet6/ip6_var.h>
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#include <netinet6/nd6.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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#include <netinet/tcp_syncache.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 TCP_OFFLOAD
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#include <netinet/tcp_offload.h>
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#endif
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#ifdef IPSEC
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#include <netipsec/ipsec.h>
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#include <netipsec/ipsec6.h>
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#endif /*IPSEC*/
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#include <machine/in_cksum.h>
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#include <security/mac/mac_framework.h>
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const int tcprexmtthresh;
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VNET_DECLARE(int, tcp_autorcvbuf_inc);
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#define V_tcp_autorcvbuf_inc VNET(tcp_autorcvbuf_inc)
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VNET_DECLARE(int, tcp_autorcvbuf_max);
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#define V_tcp_autorcvbuf_max VNET(tcp_autorcvbuf_max)
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VNET_DECLARE(int, tcp_do_rfc3042);
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#define V_tcp_do_rfc3042 VNET(tcp_do_rfc3042)
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VNET_DECLARE(int, tcp_do_autorcvbuf);
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#define V_tcp_do_autorcvbuf VNET(tcp_do_autorcvbuf)
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VNET_DECLARE(int, tcp_insecure_rst);
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#define V_tcp_insecure_rst VNET(tcp_insecure_rst)
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VNET_DECLARE(int, tcp_insecure_syn);
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#define V_tcp_insecure_syn VNET(tcp_insecure_syn)
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static void tcp_do_segment_fastslow(struct mbuf *, struct tcphdr *,
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struct socket *, struct tcpcb *, int, int, uint8_t,
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int);
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static void tcp_do_segment_fastack(struct mbuf *, struct tcphdr *,
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struct socket *, struct tcpcb *, int, int, uint8_t,
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int);
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/*
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* Indicate whether this ack should be delayed. We can delay the ack if
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* following conditions are met:
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* - There is no delayed ack timer in progress.
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* - Our last ack wasn't a 0-sized window. We never want to delay
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* the ack that opens up a 0-sized window.
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* - LRO wasn't used for this segment. We make sure by checking that the
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* segment size is not larger than the MSS.
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*/
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#define DELAY_ACK(tp, tlen) \
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((!tcp_timer_active(tp, TT_DELACK) && \
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(tp->t_flags & TF_RXWIN0SENT) == 0) && \
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(tlen <= tp->t_maxseg) && \
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(V_tcp_delack_enabled || (tp->t_flags & TF_NEEDSYN)))
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/*
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* So how is this faster than the normal fast ack?
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* It basically allows us to also stay in the fastpath
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* when a window-update ack also arrives. In testing
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* we saw only 25-30% of connections doing fastpath
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* due to the fact that along with moving forward
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* in sequence the window was also updated.
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*/
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static void
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tcp_do_fastack(struct mbuf *m, struct tcphdr *th, struct socket *so,
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struct tcpcb *tp, struct tcpopt *to, int drop_hdrlen, int tlen,
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int ti_locked, u_long tiwin)
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{
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int acked;
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int winup_only=0;
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#ifdef TCPDEBUG
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/*
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* The size of tcp_saveipgen must be the size of the max ip header,
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* now IPv6.
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*/
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u_char tcp_saveipgen[IP6_HDR_LEN];
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struct tcphdr tcp_savetcp;
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short ostate = 0;
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#endif
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/*
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* The following if statment will be true if
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* we are doing the win_up_in_fp <and>
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* - We have more new data (SEQ_LT(tp->snd_wl1, th->th_seq)) <or>
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* - No more new data, but we have an ack for new data
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* (tp->snd_wl1 == th->th_seq && SEQ_LT(tp->snd_wl2, th->th_ack))
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* - No more new data, the same ack point but the window grew
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* (tp->snd_wl1 == th->th_seq && tp->snd_wl2 == th->th_ack && twin > tp->snd_wnd)
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*/
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if ((SEQ_LT(tp->snd_wl1, th->th_seq) ||
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(tp->snd_wl1 == th->th_seq && (SEQ_LT(tp->snd_wl2, th->th_ack) ||
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(tp->snd_wl2 == th->th_ack && tiwin > tp->snd_wnd))))) {
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/* keep track of pure window updates */
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if (tp->snd_wl2 == th->th_ack && tiwin > tp->snd_wnd) {
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winup_only = 1;
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TCPSTAT_INC(tcps_rcvwinupd);
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}
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tp->snd_wnd = tiwin;
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tp->snd_wl1 = th->th_seq;
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tp->snd_wl2 = th->th_ack;
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if (tp->snd_wnd > tp->max_sndwnd)
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tp->max_sndwnd = tp->snd_wnd;
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}
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/*
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* If last ACK falls within this segment's sequence numbers,
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* record the timestamp.
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* NOTE that the test is modified according to the latest
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* proposal of the tcplw@cray.com list (Braden 1993/04/26).
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*/
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if ((to->to_flags & TOF_TS) != 0 &&
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SEQ_LEQ(th->th_seq, tp->last_ack_sent)) {
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tp->ts_recent_age = tcp_ts_getticks();
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tp->ts_recent = to->to_tsval;
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}
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/*
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* This is a pure ack for outstanding data.
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*/
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if (ti_locked == TI_RLOCKED) {
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INP_INFO_RUNLOCK(&V_tcbinfo);
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}
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ti_locked = TI_UNLOCKED;
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TCPSTAT_INC(tcps_predack);
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/*
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* "bad retransmit" recovery.
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*/
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if (tp->t_rxtshift == 1 &&
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tp->t_flags & TF_PREVVALID &&
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(int)(ticks - tp->t_badrxtwin) < 0) {
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cc_cong_signal(tp, th, CC_RTO_ERR);
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}
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/*
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* Recalculate the transmit timer / rtt.
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*
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* Some boxes send broken timestamp replies
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* during the SYN+ACK phase, ignore
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* timestamps of 0 or we could calculate a
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* huge RTT and blow up the retransmit timer.
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*/
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if ((to->to_flags & TOF_TS) != 0 &&
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to->to_tsecr) {
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u_int t;
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t = tcp_ts_getticks() - to->to_tsecr;
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if (!tp->t_rttlow || tp->t_rttlow > t)
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tp->t_rttlow = t;
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tcp_xmit_timer(tp,
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TCP_TS_TO_TICKS(t) + 1);
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} else if (tp->t_rtttime &&
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SEQ_GT(th->th_ack, tp->t_rtseq)) {
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if (!tp->t_rttlow ||
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tp->t_rttlow > ticks - tp->t_rtttime)
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tp->t_rttlow = ticks - tp->t_rtttime;
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tcp_xmit_timer(tp,
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ticks - tp->t_rtttime);
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}
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if (winup_only == 0) {
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acked = BYTES_THIS_ACK(tp, th);
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/* Run HHOOK_TCP_ESTABLISHED_IN helper hooks. */
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hhook_run_tcp_est_in(tp, th, to);
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TCPSTAT_ADD(tcps_rcvackbyte, acked);
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sbdrop(&so->so_snd, acked);
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if (SEQ_GT(tp->snd_una, tp->snd_recover) &&
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SEQ_LEQ(th->th_ack, tp->snd_recover))
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tp->snd_recover = th->th_ack - 1;
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/*
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* Let the congestion control algorithm update
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* congestion control related information. This
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* typically means increasing the congestion
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* window.
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*/
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cc_ack_received(tp, th, CC_ACK);
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tp->snd_una = th->th_ack;
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/*
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* Pull snd_wl2 up to prevent seq wrap relative
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* to th_ack.
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*/
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tp->snd_wl2 = th->th_ack;
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tp->t_dupacks = 0;
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m_freem(m);
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/*
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* If all outstanding data are acked, stop
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* retransmit timer, otherwise restart timer
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* using current (possibly backed-off) value.
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* If process is waiting for space,
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* wakeup/selwakeup/signal. If data
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* are ready to send, let tcp_output
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* decide between more output or persist.
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*/
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#ifdef TCPDEBUG
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if (so->so_options & SO_DEBUG)
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tcp_trace(TA_INPUT, ostate, tp,
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(void *)tcp_saveipgen,
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&tcp_savetcp, 0);
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#endif
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if (tp->snd_una == tp->snd_max)
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tcp_timer_activate(tp, TT_REXMT, 0);
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else if (!tcp_timer_active(tp, TT_PERSIST))
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tcp_timer_activate(tp, TT_REXMT,
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tp->t_rxtcur);
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} else {
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/*
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* Window update only, just free the mbufs and
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* send out whatever we can.
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*/
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m_freem(m);
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}
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sowwakeup(so);
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if (sbavail(&so->so_snd))
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(void) tcp_output(tp);
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KASSERT(ti_locked == TI_UNLOCKED, ("%s: check_delack ti_locked %d",
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__func__, ti_locked));
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INP_INFO_UNLOCK_ASSERT(&V_tcbinfo);
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INP_WLOCK_ASSERT(tp->t_inpcb);
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if (tp->t_flags & TF_DELACK) {
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tp->t_flags &= ~TF_DELACK;
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tcp_timer_activate(tp, TT_DELACK, tcp_delacktime);
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}
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INP_WUNLOCK(tp->t_inpcb);
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}
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/*
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* Here nothing is really faster, its just that we
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* have broken out the fast-data path also just like
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* the fast-ack.
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*/
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static void
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tcp_do_fastnewdata(struct mbuf *m, struct tcphdr *th, struct socket *so,
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struct tcpcb *tp, struct tcpopt *to, int drop_hdrlen, int tlen,
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int ti_locked, u_long tiwin)
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{
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int newsize = 0; /* automatic sockbuf scaling */
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#ifdef TCPDEBUG
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/*
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* The size of tcp_saveipgen must be the size of the max ip header,
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* now IPv6.
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*/
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u_char tcp_saveipgen[IP6_HDR_LEN];
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struct tcphdr tcp_savetcp;
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short ostate = 0;
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#endif
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/*
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* If last ACK falls within this segment's sequence numbers,
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* record the timestamp.
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* NOTE that the test is modified according to the latest
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* proposal of the tcplw@cray.com list (Braden 1993/04/26).
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*/
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if ((to->to_flags & TOF_TS) != 0 &&
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SEQ_LEQ(th->th_seq, tp->last_ack_sent)) {
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tp->ts_recent_age = tcp_ts_getticks();
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tp->ts_recent = to->to_tsval;
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}
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/*
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* This is a pure, in-sequence data packet with
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* nothing on the reassembly queue and we have enough
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* buffer space to take it.
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*/
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if (ti_locked == TI_RLOCKED) {
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INP_INFO_RUNLOCK(&V_tcbinfo);
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}
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ti_locked = TI_UNLOCKED;
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/* Clean receiver SACK report if present */
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if ((tp->t_flags & TF_SACK_PERMIT) && tp->rcv_numsacks)
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tcp_clean_sackreport(tp);
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TCPSTAT_INC(tcps_preddat);
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tp->rcv_nxt += tlen;
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/*
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* Pull snd_wl1 up to prevent seq wrap relative to
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* th_seq.
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*/
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tp->snd_wl1 = th->th_seq;
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/*
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* Pull rcv_up up to prevent seq wrap relative to
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* rcv_nxt.
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*/
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tp->rcv_up = tp->rcv_nxt;
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TCPSTAT_ADD(tcps_rcvbyte, tlen);
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#ifdef TCPDEBUG
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if (so->so_options & SO_DEBUG)
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tcp_trace(TA_INPUT, ostate, tp,
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(void *)tcp_saveipgen, &tcp_savetcp, 0);
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#endif
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/*
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* Automatic sizing of receive socket buffer. Often the send
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* buffer size is not optimally adjusted to the actual network
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* conditions at hand (delay bandwidth product). Setting the
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* buffer size too small limits throughput on links with high
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* bandwidth and high delay (eg. trans-continental/oceanic links).
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*
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* On the receive side the socket buffer memory is only rarely
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* used to any significant extent. This allows us to be much
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* more aggressive in scaling the receive socket buffer. For
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* the case that the buffer space is actually used to a large
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* extent and we run out of kernel memory we can simply drop
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* the new segments; TCP on the sender will just retransmit it
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* later. Setting the buffer size too big may only consume too
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* much kernel memory if the application doesn't read() from
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* the socket or packet loss or reordering makes use of the
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* reassembly queue.
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*
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* The criteria to step up the receive buffer one notch are:
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* 1. Application has not set receive buffer size with
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* SO_RCVBUF. Setting SO_RCVBUF clears SB_AUTOSIZE.
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* 2. the number of bytes received during the time it takes
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* one timestamp to be reflected back to us (the RTT);
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* 3. received bytes per RTT is within seven eighth of the
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* current socket buffer size;
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* 4. receive buffer size has not hit maximal automatic size;
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*
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* This algorithm does one step per RTT at most and only if
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* we receive a bulk stream w/o packet losses or reorderings.
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* Shrinking the buffer during idle times is not necessary as
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* it doesn't consume any memory when idle.
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*
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* TODO: Only step up if the application is actually serving
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* the buffer to better manage the socket buffer resources.
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*/
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if (V_tcp_do_autorcvbuf &&
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(to->to_flags & TOF_TS) &&
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to->to_tsecr &&
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(so->so_rcv.sb_flags & SB_AUTOSIZE)) {
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if (TSTMP_GT(to->to_tsecr, tp->rfbuf_ts) &&
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to->to_tsecr - tp->rfbuf_ts < hz) {
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if (tp->rfbuf_cnt >
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(so->so_rcv.sb_hiwat / 8 * 7) &&
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so->so_rcv.sb_hiwat <
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V_tcp_autorcvbuf_max) {
|
|
newsize =
|
|
min(so->so_rcv.sb_hiwat +
|
|
V_tcp_autorcvbuf_inc,
|
|
V_tcp_autorcvbuf_max);
|
|
}
|
|
/* Start over with next RTT. */
|
|
tp->rfbuf_ts = 0;
|
|
tp->rfbuf_cnt = 0;
|
|
} else
|
|
tp->rfbuf_cnt += tlen; /* add up */
|
|
}
|
|
|
|
/* Add data to socket buffer. */
|
|
SOCKBUF_LOCK(&so->so_rcv);
|
|
if (so->so_rcv.sb_state & SBS_CANTRCVMORE) {
|
|
m_freem(m);
|
|
} else {
|
|
/*
|
|
* Set new socket buffer size.
|
|
* Give up when limit is reached.
|
|
*/
|
|
if (newsize)
|
|
if (!sbreserve_locked(&so->so_rcv,
|
|
newsize, so, NULL))
|
|
so->so_rcv.sb_flags &= ~SB_AUTOSIZE;
|
|
m_adj(m, drop_hdrlen); /* delayed header drop */
|
|
sbappendstream_locked(&so->so_rcv, m, 0);
|
|
}
|
|
/* NB: sorwakeup_locked() does an implicit unlock. */
|
|
sorwakeup_locked(so);
|
|
if (DELAY_ACK(tp, tlen)) {
|
|
tp->t_flags |= TF_DELACK;
|
|
} else {
|
|
tp->t_flags |= TF_ACKNOW;
|
|
tcp_output(tp);
|
|
}
|
|
KASSERT(ti_locked == TI_UNLOCKED, ("%s: check_delack ti_locked %d",
|
|
__func__, ti_locked));
|
|
INP_INFO_UNLOCK_ASSERT(&V_tcbinfo);
|
|
INP_WLOCK_ASSERT(tp->t_inpcb);
|
|
|
|
if (tp->t_flags & TF_DELACK) {
|
|
tp->t_flags &= ~TF_DELACK;
|
|
tcp_timer_activate(tp, TT_DELACK, tcp_delacktime);
|
|
}
|
|
INP_WUNLOCK(tp->t_inpcb);
|
|
}
|
|
|
|
/*
|
|
* The slow-path is the clone of the long long part
|
|
* of tcp_do_segment past all the fast-path stuff. We
|
|
* use it here by two different callers, the fast/slow and
|
|
* the fastack only.
|
|
*/
|
|
static void
|
|
tcp_do_slowpath(struct mbuf *m, struct tcphdr *th, struct socket *so,
|
|
struct tcpcb *tp, struct tcpopt *to, int drop_hdrlen, int tlen,
|
|
int ti_locked, u_long tiwin, int thflags)
|
|
{
|
|
int acked, ourfinisacked, needoutput = 0;
|
|
int rstreason, todrop, win;
|
|
char *s;
|
|
struct in_conninfo *inc;
|
|
struct mbuf *mfree = NULL;
|
|
#ifdef TCPDEBUG
|
|
/*
|
|
* The size of tcp_saveipgen must be the size of the max ip header,
|
|
* now IPv6.
|
|
*/
|
|
u_char tcp_saveipgen[IP6_HDR_LEN];
|
|
struct tcphdr tcp_savetcp;
|
|
short ostate = 0;
|
|
#endif
|
|
/*
|
|
* Calculate amount of space in receive window,
|
|
* and then do TCP input processing.
|
|
* Receive window is amount of space in rcv queue,
|
|
* but not less than advertised window.
|
|
*/
|
|
inc = &tp->t_inpcb->inp_inc;
|
|
win = sbspace(&so->so_rcv);
|
|
if (win < 0)
|
|
win = 0;
|
|
tp->rcv_wnd = imax(win, (int)(tp->rcv_adv - tp->rcv_nxt));
|
|
|
|
/* Reset receive buffer auto scaling when not in bulk receive mode. */
|
|
tp->rfbuf_ts = 0;
|
|
tp->rfbuf_cnt = 0;
|
|
|
|
switch (tp->t_state) {
|
|
|
|
/*
|
|
* If the state is SYN_RECEIVED:
|
|
* if seg contains an ACK, but not for our SYN/ACK, send a RST.
|
|
*/
|
|
case TCPS_SYN_RECEIVED:
|
|
if ((thflags & TH_ACK) &&
|
|
(SEQ_LEQ(th->th_ack, tp->snd_una) ||
|
|
SEQ_GT(th->th_ack, tp->snd_max))) {
|
|
rstreason = BANDLIM_RST_OPENPORT;
|
|
goto dropwithreset;
|
|
}
|
|
break;
|
|
|
|
/*
|
|
* If the state is SYN_SENT:
|
|
* if seg contains an ACK, but not for our SYN, drop the input.
|
|
* if seg contains a RST, then drop the connection.
|
|
* if seg does not contain SYN, then drop it.
|
|
* Otherwise this is an acceptable SYN segment
|
|
* initialize tp->rcv_nxt and tp->irs
|
|
* if seg contains ack then advance tp->snd_una
|
|
* if seg contains an ECE and ECN support is enabled, the stream
|
|
* is ECN capable.
|
|
* if SYN has been acked change to ESTABLISHED else SYN_RCVD state
|
|
* arrange for segment to be acked (eventually)
|
|
* continue processing rest of data/controls, beginning with URG
|
|
*/
|
|
case TCPS_SYN_SENT:
|
|
if ((thflags & TH_ACK) &&
|
|
(SEQ_LEQ(th->th_ack, tp->iss) ||
|
|
SEQ_GT(th->th_ack, tp->snd_max))) {
|
|
rstreason = BANDLIM_UNLIMITED;
|
|
goto dropwithreset;
|
|
}
|
|
if ((thflags & (TH_ACK|TH_RST)) == (TH_ACK|TH_RST)) {
|
|
TCP_PROBE5(connect__refused, NULL, tp,
|
|
mtod(m, const char *), tp, th);
|
|
tp = tcp_drop(tp, ECONNREFUSED);
|
|
}
|
|
if (thflags & TH_RST)
|
|
goto drop;
|
|
if (!(thflags & TH_SYN))
|
|
goto drop;
|
|
|
|
tp->irs = th->th_seq;
|
|
tcp_rcvseqinit(tp);
|
|
if (thflags & TH_ACK) {
|
|
TCPSTAT_INC(tcps_connects);
|
|
soisconnected(so);
|
|
#ifdef MAC
|
|
mac_socketpeer_set_from_mbuf(m, so);
|
|
#endif
|
|
/* Do window scaling on this connection? */
|
|
if ((tp->t_flags & (TF_RCVD_SCALE|TF_REQ_SCALE)) ==
|
|
(TF_RCVD_SCALE|TF_REQ_SCALE)) {
|
|
tp->rcv_scale = tp->request_r_scale;
|
|
}
|
|
tp->rcv_adv += imin(tp->rcv_wnd,
|
|
TCP_MAXWIN << tp->rcv_scale);
|
|
tp->snd_una++; /* SYN is acked */
|
|
/*
|
|
* If there's data, delay ACK; if there's also a FIN
|
|
* ACKNOW will be turned on later.
|
|
*/
|
|
if (DELAY_ACK(tp, tlen) && tlen != 0)
|
|
tcp_timer_activate(tp, TT_DELACK,
|
|
tcp_delacktime);
|
|
else
|
|
tp->t_flags |= TF_ACKNOW;
|
|
|
|
if ((thflags & TH_ECE) && V_tcp_do_ecn) {
|
|
tp->t_flags |= TF_ECN_PERMIT;
|
|
TCPSTAT_INC(tcps_ecn_shs);
|
|
}
|
|
|
|
/*
|
|
* Received <SYN,ACK> in SYN_SENT[*] state.
|
|
* Transitions:
|
|
* SYN_SENT --> ESTABLISHED
|
|
* SYN_SENT* --> FIN_WAIT_1
|
|
*/
|
|
tp->t_starttime = ticks;
|
|
if (tp->t_flags & TF_NEEDFIN) {
|
|
tcp_state_change(tp, TCPS_FIN_WAIT_1);
|
|
tp->t_flags &= ~TF_NEEDFIN;
|
|
thflags &= ~TH_SYN;
|
|
} else {
|
|
tcp_state_change(tp, TCPS_ESTABLISHED);
|
|
TCP_PROBE5(connect__established, NULL, tp,
|
|
mtod(m, const char *), tp, th);
|
|
cc_conn_init(tp);
|
|
tcp_timer_activate(tp, TT_KEEP,
|
|
TP_KEEPIDLE(tp));
|
|
}
|
|
} else {
|
|
/*
|
|
* Received initial SYN in SYN-SENT[*] state =>
|
|
* simultaneous open.
|
|
* If it succeeds, connection is * half-synchronized.
|
|
* Otherwise, do 3-way handshake:
|
|
* SYN-SENT -> SYN-RECEIVED
|
|
* SYN-SENT* -> SYN-RECEIVED*
|
|
*/
|
|
tp->t_flags |= (TF_ACKNOW | TF_NEEDSYN);
|
|
tcp_timer_activate(tp, TT_REXMT, 0);
|
|
tcp_state_change(tp, TCPS_SYN_RECEIVED);
|
|
}
|
|
|
|
KASSERT(ti_locked == TI_RLOCKED, ("%s: trimthenstep6: "
|
|
"ti_locked %d", __func__, ti_locked));
|
|
INP_INFO_RLOCK_ASSERT(&V_tcbinfo);
|
|
INP_WLOCK_ASSERT(tp->t_inpcb);
|
|
|
|
/*
|
|
* Advance th->th_seq to correspond to first data byte.
|
|
* If data, trim to stay within window,
|
|
* dropping FIN if necessary.
|
|
*/
|
|
th->th_seq++;
|
|
if (tlen > tp->rcv_wnd) {
|
|
todrop = tlen - tp->rcv_wnd;
|
|
m_adj(m, -todrop);
|
|
tlen = tp->rcv_wnd;
|
|
thflags &= ~TH_FIN;
|
|
TCPSTAT_INC(tcps_rcvpackafterwin);
|
|
TCPSTAT_ADD(tcps_rcvbyteafterwin, todrop);
|
|
}
|
|
tp->snd_wl1 = th->th_seq - 1;
|
|
tp->rcv_up = th->th_seq;
|
|
/*
|
|
* Client side of transaction: already sent SYN and data.
|
|
* If the remote host used T/TCP to validate the SYN,
|
|
* our data will be ACK'd; if so, enter normal data segment
|
|
* processing in the middle of step 5, ack processing.
|
|
* Otherwise, goto step 6.
|
|
*/
|
|
if (thflags & TH_ACK)
|
|
goto process_ACK;
|
|
|
|
goto step6;
|
|
|
|
/*
|
|
* If the state is LAST_ACK or CLOSING or TIME_WAIT:
|
|
* do normal processing.
|
|
*
|
|
* NB: Leftover from RFC1644 T/TCP. Cases to be reused later.
|
|
*/
|
|
case TCPS_LAST_ACK:
|
|
case TCPS_CLOSING:
|
|
break; /* continue normal processing */
|
|
}
|
|
|
|
/*
|
|
* States other than LISTEN or SYN_SENT.
|
|
* First check the RST flag and sequence number since reset segments
|
|
* are exempt from the timestamp and connection count tests. This
|
|
* fixes a bug introduced by the Stevens, vol. 2, p. 960 bugfix
|
|
* below which allowed reset segments in half the sequence space
|
|
* to fall though and be processed (which gives forged reset
|
|
* segments with a random sequence number a 50 percent chance of
|
|
* killing a connection).
|
|
* Then check timestamp, if present.
|
|
* Then check the connection count, if present.
|
|
* Then check that at least some bytes of segment are within
|
|
* receive window. If segment begins before rcv_nxt,
|
|
* drop leading data (and SYN); if nothing left, just ack.
|
|
*/
|
|
if (thflags & TH_RST) {
|
|
/*
|
|
* RFC5961 Section 3.2
|
|
*
|
|
* - RST drops connection only if SEG.SEQ == RCV.NXT.
|
|
* - If RST is in window, we send challenge ACK.
|
|
*
|
|
* Note: to take into account delayed ACKs, we should
|
|
* test against last_ack_sent instead of rcv_nxt.
|
|
* Note 2: we handle special case of closed window, not
|
|
* covered by the RFC.
|
|
*/
|
|
if ((SEQ_GEQ(th->th_seq, tp->last_ack_sent) &&
|
|
SEQ_LT(th->th_seq, tp->last_ack_sent + tp->rcv_wnd)) ||
|
|
(tp->rcv_wnd == 0 && tp->last_ack_sent == th->th_seq)) {
|
|
INP_INFO_RLOCK_ASSERT(&V_tcbinfo);
|
|
KASSERT(ti_locked == TI_RLOCKED,
|
|
("%s: TH_RST ti_locked %d, th %p tp %p",
|
|
__func__, ti_locked, th, tp));
|
|
KASSERT(tp->t_state != TCPS_SYN_SENT,
|
|
("%s: TH_RST for TCPS_SYN_SENT th %p tp %p",
|
|
__func__, th, tp));
|
|
|
|
if (V_tcp_insecure_rst ||
|
|
tp->last_ack_sent == th->th_seq) {
|
|
TCPSTAT_INC(tcps_drops);
|
|
/* Drop the connection. */
|
|
switch (tp->t_state) {
|
|
case TCPS_SYN_RECEIVED:
|
|
so->so_error = ECONNREFUSED;
|
|
goto close;
|
|
case TCPS_ESTABLISHED:
|
|
case TCPS_FIN_WAIT_1:
|
|
case TCPS_FIN_WAIT_2:
|
|
case TCPS_CLOSE_WAIT:
|
|
so->so_error = ECONNRESET;
|
|
close:
|
|
tcp_state_change(tp, TCPS_CLOSED);
|
|
/* FALLTHROUGH */
|
|
default:
|
|
tp = tcp_close(tp);
|
|
}
|
|
} else {
|
|
TCPSTAT_INC(tcps_badrst);
|
|
/* Send challenge ACK. */
|
|
tcp_respond(tp, mtod(m, void *), th, m,
|
|
tp->rcv_nxt, tp->snd_nxt, TH_ACK);
|
|
tp->last_ack_sent = tp->rcv_nxt;
|
|
m = NULL;
|
|
}
|
|
}
|
|
goto drop;
|
|
}
|
|
|
|
/*
|
|
* RFC5961 Section 4.2
|
|
* Send challenge ACK for any SYN in synchronized state.
|
|
*/
|
|
if ((thflags & TH_SYN) && tp->t_state != TCPS_SYN_SENT) {
|
|
KASSERT(ti_locked == TI_RLOCKED,
|
|
("tcp_do_segment: TH_SYN ti_locked %d", ti_locked));
|
|
INP_INFO_RLOCK_ASSERT(&V_tcbinfo);
|
|
|
|
TCPSTAT_INC(tcps_badsyn);
|
|
if (V_tcp_insecure_syn &&
|
|
SEQ_GEQ(th->th_seq, tp->last_ack_sent) &&
|
|
SEQ_LT(th->th_seq, tp->last_ack_sent + tp->rcv_wnd)) {
|
|
tp = tcp_drop(tp, ECONNRESET);
|
|
rstreason = BANDLIM_UNLIMITED;
|
|
} else {
|
|
/* Send challenge ACK. */
|
|
tcp_respond(tp, mtod(m, void *), th, m, tp->rcv_nxt,
|
|
tp->snd_nxt, TH_ACK);
|
|
tp->last_ack_sent = tp->rcv_nxt;
|
|
m = NULL;
|
|
}
|
|
goto drop;
|
|
}
|
|
|
|
/*
|
|
* RFC 1323 PAWS: If we have a timestamp reply on this segment
|
|
* and it's less than ts_recent, drop it.
|
|
*/
|
|
if ((to->to_flags & TOF_TS) != 0 && tp->ts_recent &&
|
|
TSTMP_LT(to->to_tsval, tp->ts_recent)) {
|
|
|
|
/* Check to see if ts_recent is over 24 days old. */
|
|
if (tcp_ts_getticks() - tp->ts_recent_age > TCP_PAWS_IDLE) {
|
|
/*
|
|
* Invalidate ts_recent. If this segment updates
|
|
* ts_recent, the age will be reset later and ts_recent
|
|
* will get a valid value. If it does not, setting
|
|
* ts_recent to zero will at least satisfy the
|
|
* requirement that zero be placed in the timestamp
|
|
* echo reply when ts_recent isn't valid. The
|
|
* age isn't reset until we get a valid ts_recent
|
|
* because we don't want out-of-order segments to be
|
|
* dropped when ts_recent is old.
|
|
*/
|
|
tp->ts_recent = 0;
|
|
} else {
|
|
TCPSTAT_INC(tcps_rcvduppack);
|
|
TCPSTAT_ADD(tcps_rcvdupbyte, tlen);
|
|
TCPSTAT_INC(tcps_pawsdrop);
|
|
if (tlen)
|
|
goto dropafterack;
|
|
goto drop;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* In the SYN-RECEIVED state, validate that the packet belongs to
|
|
* this connection before trimming the data to fit the receive
|
|
* window. Check the sequence number versus IRS since we know
|
|
* the sequence numbers haven't wrapped. This is a partial fix
|
|
* for the "LAND" DoS attack.
|
|
*/
|
|
if (tp->t_state == TCPS_SYN_RECEIVED && SEQ_LT(th->th_seq, tp->irs)) {
|
|
rstreason = BANDLIM_RST_OPENPORT;
|
|
goto dropwithreset;
|
|
}
|
|
|
|
todrop = tp->rcv_nxt - th->th_seq;
|
|
if (todrop > 0) {
|
|
if (thflags & TH_SYN) {
|
|
thflags &= ~TH_SYN;
|
|
th->th_seq++;
|
|
if (th->th_urp > 1)
|
|
th->th_urp--;
|
|
else
|
|
thflags &= ~TH_URG;
|
|
todrop--;
|
|
}
|
|
/*
|
|
* Following if statement from Stevens, vol. 2, p. 960.
|
|
*/
|
|
if (todrop > tlen
|
|
|| (todrop == tlen && (thflags & TH_FIN) == 0)) {
|
|
/*
|
|
* Any valid FIN must be to the left of the window.
|
|
* At this point the FIN must be a duplicate or out
|
|
* of sequence; drop it.
|
|
*/
|
|
thflags &= ~TH_FIN;
|
|
|
|
/*
|
|
* Send an ACK to resynchronize and drop any data.
|
|
* But keep on processing for RST or ACK.
|
|
*/
|
|
tp->t_flags |= TF_ACKNOW;
|
|
todrop = tlen;
|
|
TCPSTAT_INC(tcps_rcvduppack);
|
|
TCPSTAT_ADD(tcps_rcvdupbyte, todrop);
|
|
} else {
|
|
TCPSTAT_INC(tcps_rcvpartduppack);
|
|
TCPSTAT_ADD(tcps_rcvpartdupbyte, todrop);
|
|
}
|
|
drop_hdrlen += todrop; /* drop from the top afterwards */
|
|
th->th_seq += todrop;
|
|
tlen -= todrop;
|
|
if (th->th_urp > todrop)
|
|
th->th_urp -= todrop;
|
|
else {
|
|
thflags &= ~TH_URG;
|
|
th->th_urp = 0;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* If new data are received on a connection after the
|
|
* user processes are gone, then RST the other end.
|
|
*/
|
|
if ((so->so_state & SS_NOFDREF) &&
|
|
tp->t_state > TCPS_CLOSE_WAIT && tlen) {
|
|
KASSERT(ti_locked == TI_RLOCKED, ("%s: SS_NOFDEREF && "
|
|
"CLOSE_WAIT && tlen ti_locked %d", __func__, ti_locked));
|
|
INP_INFO_RLOCK_ASSERT(&V_tcbinfo);
|
|
|
|
if ((s = tcp_log_addrs(inc, th, NULL, NULL))) {
|
|
log(LOG_DEBUG, "%s; %s: %s: Received %d bytes of data "
|
|
"after socket was closed, "
|
|
"sending RST and removing tcpcb\n",
|
|
s, __func__, tcpstates[tp->t_state], tlen);
|
|
free(s, M_TCPLOG);
|
|
}
|
|
tp = tcp_close(tp);
|
|
TCPSTAT_INC(tcps_rcvafterclose);
|
|
rstreason = BANDLIM_UNLIMITED;
|
|
goto dropwithreset;
|
|
}
|
|
|
|
/*
|
|
* If segment ends after window, drop trailing data
|
|
* (and PUSH and FIN); if nothing left, just ACK.
|
|
*/
|
|
todrop = (th->th_seq + tlen) - (tp->rcv_nxt + tp->rcv_wnd);
|
|
if (todrop > 0) {
|
|
TCPSTAT_INC(tcps_rcvpackafterwin);
|
|
if (todrop >= tlen) {
|
|
TCPSTAT_ADD(tcps_rcvbyteafterwin, tlen);
|
|
/*
|
|
* If window is closed can only take segments at
|
|
* window edge, and have to drop data and PUSH from
|
|
* incoming segments. Continue processing, but
|
|
* remember to ack. Otherwise, drop segment
|
|
* and ack.
|
|
*/
|
|
if (tp->rcv_wnd == 0 && th->th_seq == tp->rcv_nxt) {
|
|
tp->t_flags |= TF_ACKNOW;
|
|
TCPSTAT_INC(tcps_rcvwinprobe);
|
|
} else
|
|
goto dropafterack;
|
|
} else
|
|
TCPSTAT_ADD(tcps_rcvbyteafterwin, todrop);
|
|
m_adj(m, -todrop);
|
|
tlen -= todrop;
|
|
thflags &= ~(TH_PUSH|TH_FIN);
|
|
}
|
|
|
|
/*
|
|
* If last ACK falls within this segment's sequence numbers,
|
|
* record its timestamp.
|
|
* NOTE:
|
|
* 1) That the test incorporates suggestions from the latest
|
|
* proposal of the tcplw@cray.com list (Braden 1993/04/26).
|
|
* 2) That updating only on newer timestamps interferes with
|
|
* our earlier PAWS tests, so this check should be solely
|
|
* predicated on the sequence space of this segment.
|
|
* 3) That we modify the segment boundary check to be
|
|
* Last.ACK.Sent <= SEG.SEQ + SEG.Len
|
|
* instead of RFC1323's
|
|
* Last.ACK.Sent < SEG.SEQ + SEG.Len,
|
|
* This modified check allows us to overcome RFC1323's
|
|
* limitations as described in Stevens TCP/IP Illustrated
|
|
* Vol. 2 p.869. In such cases, we can still calculate the
|
|
* RTT correctly when RCV.NXT == Last.ACK.Sent.
|
|
*/
|
|
if ((to->to_flags & TOF_TS) != 0 &&
|
|
SEQ_LEQ(th->th_seq, tp->last_ack_sent) &&
|
|
SEQ_LEQ(tp->last_ack_sent, th->th_seq + tlen +
|
|
((thflags & (TH_SYN|TH_FIN)) != 0))) {
|
|
tp->ts_recent_age = tcp_ts_getticks();
|
|
tp->ts_recent = to->to_tsval;
|
|
}
|
|
|
|
/*
|
|
* If the ACK bit is off: if in SYN-RECEIVED state or SENDSYN
|
|
* flag is on (half-synchronized state), then queue data for
|
|
* later processing; else drop segment and return.
|
|
*/
|
|
if ((thflags & TH_ACK) == 0) {
|
|
if (tp->t_state == TCPS_SYN_RECEIVED ||
|
|
(tp->t_flags & TF_NEEDSYN))
|
|
goto step6;
|
|
else if (tp->t_flags & TF_ACKNOW)
|
|
goto dropafterack;
|
|
else
|
|
goto drop;
|
|
}
|
|
|
|
/*
|
|
* Ack processing.
|
|
*/
|
|
switch (tp->t_state) {
|
|
|
|
/*
|
|
* In SYN_RECEIVED state, the ack ACKs our SYN, so enter
|
|
* ESTABLISHED state and continue processing.
|
|
* The ACK was checked above.
|
|
*/
|
|
case TCPS_SYN_RECEIVED:
|
|
|
|
TCPSTAT_INC(tcps_connects);
|
|
soisconnected(so);
|
|
/* Do window scaling? */
|
|
if ((tp->t_flags & (TF_RCVD_SCALE|TF_REQ_SCALE)) ==
|
|
(TF_RCVD_SCALE|TF_REQ_SCALE)) {
|
|
tp->rcv_scale = tp->request_r_scale;
|
|
tp->snd_wnd = tiwin;
|
|
}
|
|
/*
|
|
* Make transitions:
|
|
* SYN-RECEIVED -> ESTABLISHED
|
|
* SYN-RECEIVED* -> FIN-WAIT-1
|
|
*/
|
|
tp->t_starttime = ticks;
|
|
if (tp->t_flags & TF_NEEDFIN) {
|
|
tcp_state_change(tp, TCPS_FIN_WAIT_1);
|
|
tp->t_flags &= ~TF_NEEDFIN;
|
|
} else {
|
|
tcp_state_change(tp, TCPS_ESTABLISHED);
|
|
TCP_PROBE5(accept__established, NULL, tp,
|
|
mtod(m, const char *), tp, th);
|
|
cc_conn_init(tp);
|
|
tcp_timer_activate(tp, TT_KEEP, TP_KEEPIDLE(tp));
|
|
}
|
|
/*
|
|
* If segment contains data or ACK, will call tcp_reass()
|
|
* later; if not, do so now to pass queued data to user.
|
|
*/
|
|
if (tlen == 0 && (thflags & TH_FIN) == 0)
|
|
(void) tcp_reass(tp, (struct tcphdr *)0, 0,
|
|
(struct mbuf *)0);
|
|
tp->snd_wl1 = th->th_seq - 1;
|
|
/* FALLTHROUGH */
|
|
|
|
/*
|
|
* In ESTABLISHED state: drop duplicate ACKs; ACK out of range
|
|
* ACKs. If the ack is in the range
|
|
* tp->snd_una < th->th_ack <= tp->snd_max
|
|
* then advance tp->snd_una to th->th_ack and drop
|
|
* data from the retransmission queue. If this ACK reflects
|
|
* more up to date window information we update our window information.
|
|
*/
|
|
case TCPS_ESTABLISHED:
|
|
case TCPS_FIN_WAIT_1:
|
|
case TCPS_FIN_WAIT_2:
|
|
case TCPS_CLOSE_WAIT:
|
|
case TCPS_CLOSING:
|
|
case TCPS_LAST_ACK:
|
|
if (SEQ_GT(th->th_ack, tp->snd_max)) {
|
|
TCPSTAT_INC(tcps_rcvacktoomuch);
|
|
goto dropafterack;
|
|
}
|
|
if ((tp->t_flags & TF_SACK_PERMIT) &&
|
|
((to->to_flags & TOF_SACK) ||
|
|
!TAILQ_EMPTY(&tp->snd_holes)))
|
|
tcp_sack_doack(tp, to, th->th_ack);
|
|
else
|
|
/*
|
|
* Reset the value so that previous (valid) value
|
|
* from the last ack with SACK doesn't get used.
|
|
*/
|
|
tp->sackhint.sacked_bytes = 0;
|
|
|
|
/* Run HHOOK_TCP_ESTABLISHED_IN helper hooks. */
|
|
hhook_run_tcp_est_in(tp, th, to);
|
|
|
|
if (SEQ_LEQ(th->th_ack, tp->snd_una)) {
|
|
if (tlen == 0 && tiwin == tp->snd_wnd) {
|
|
/*
|
|
* If this is the first time we've seen a
|
|
* FIN from the remote, this is not a
|
|
* duplicate and it needs to be processed
|
|
* normally. This happens during a
|
|
* simultaneous close.
|
|
*/
|
|
if ((thflags & TH_FIN) &&
|
|
(TCPS_HAVERCVDFIN(tp->t_state) == 0)) {
|
|
tp->t_dupacks = 0;
|
|
break;
|
|
}
|
|
TCPSTAT_INC(tcps_rcvdupack);
|
|
/*
|
|
* If we have outstanding data (other than
|
|
* a window probe), this is a completely
|
|
* duplicate ack (ie, window info didn't
|
|
* change and FIN isn't set),
|
|
* the ack is the biggest we've
|
|
* seen and we've seen exactly our rexmt
|
|
* threshhold of them, assume a packet
|
|
* has been dropped and retransmit it.
|
|
* Kludge snd_nxt & the congestion
|
|
* window so we send only this one
|
|
* packet.
|
|
*
|
|
* We know we're losing at the current
|
|
* window size so do congestion avoidance
|
|
* (set ssthresh to half the current window
|
|
* and pull our congestion window back to
|
|
* the new ssthresh).
|
|
*
|
|
* Dup acks mean that packets have left the
|
|
* network (they're now cached at the receiver)
|
|
* so bump cwnd by the amount in the receiver
|
|
* to keep a constant cwnd packets in the
|
|
* network.
|
|
*
|
|
* When using TCP ECN, notify the peer that
|
|
* we reduced the cwnd.
|
|
*/
|
|
if (!tcp_timer_active(tp, TT_REXMT) ||
|
|
th->th_ack != tp->snd_una)
|
|
tp->t_dupacks = 0;
|
|
else if (++tp->t_dupacks > tcprexmtthresh ||
|
|
IN_FASTRECOVERY(tp->t_flags)) {
|
|
cc_ack_received(tp, th, CC_DUPACK);
|
|
if ((tp->t_flags & TF_SACK_PERMIT) &&
|
|
IN_FASTRECOVERY(tp->t_flags)) {
|
|
int awnd;
|
|
|
|
/*
|
|
* Compute the amount of data in flight first.
|
|
* We can inject new data into the pipe iff
|
|
* we have less than 1/2 the original window's
|
|
* worth of data in flight.
|
|
*/
|
|
if (V_tcp_do_rfc6675_pipe)
|
|
awnd = tcp_compute_pipe(tp);
|
|
else
|
|
awnd = (tp->snd_nxt - tp->snd_fack) +
|
|
tp->sackhint.sack_bytes_rexmit;
|
|
|
|
if (awnd < tp->snd_ssthresh) {
|
|
tp->snd_cwnd += tp->t_maxseg;
|
|
if (tp->snd_cwnd > tp->snd_ssthresh)
|
|
tp->snd_cwnd = tp->snd_ssthresh;
|
|
}
|
|
} else
|
|
tp->snd_cwnd += tp->t_maxseg;
|
|
(void) tp->t_fb->tfb_tcp_output(tp);
|
|
goto drop;
|
|
} else if (tp->t_dupacks == tcprexmtthresh) {
|
|
tcp_seq onxt = tp->snd_nxt;
|
|
|
|
/*
|
|
* If we're doing sack, check to
|
|
* see if we're already in sack
|
|
* recovery. If we're not doing sack,
|
|
* check to see if we're in newreno
|
|
* recovery.
|
|
*/
|
|
if (tp->t_flags & TF_SACK_PERMIT) {
|
|
if (IN_FASTRECOVERY(tp->t_flags)) {
|
|
tp->t_dupacks = 0;
|
|
break;
|
|
}
|
|
} else {
|
|
if (SEQ_LEQ(th->th_ack,
|
|
tp->snd_recover)) {
|
|
tp->t_dupacks = 0;
|
|
break;
|
|
}
|
|
}
|
|
/* Congestion signal before ack. */
|
|
cc_cong_signal(tp, th, CC_NDUPACK);
|
|
cc_ack_received(tp, th, CC_DUPACK);
|
|
tcp_timer_activate(tp, TT_REXMT, 0);
|
|
tp->t_rtttime = 0;
|
|
if (tp->t_flags & TF_SACK_PERMIT) {
|
|
TCPSTAT_INC(
|
|
tcps_sack_recovery_episode);
|
|
tp->sack_newdata = tp->snd_nxt;
|
|
tp->snd_cwnd = tp->t_maxseg;
|
|
(void) tp->t_fb->tfb_tcp_output(tp);
|
|
goto drop;
|
|
}
|
|
tp->snd_nxt = th->th_ack;
|
|
tp->snd_cwnd = tp->t_maxseg;
|
|
(void) tp->t_fb->tfb_tcp_output(tp);
|
|
KASSERT(tp->snd_limited <= 2,
|
|
("%s: tp->snd_limited too big",
|
|
__func__));
|
|
tp->snd_cwnd = tp->snd_ssthresh +
|
|
tp->t_maxseg *
|
|
(tp->t_dupacks - tp->snd_limited);
|
|
if (SEQ_GT(onxt, tp->snd_nxt))
|
|
tp->snd_nxt = onxt;
|
|
goto drop;
|
|
} else if (V_tcp_do_rfc3042) {
|
|
/*
|
|
* Process first and second duplicate
|
|
* ACKs. Each indicates a segment
|
|
* leaving the network, creating room
|
|
* for more. Make sure we can send a
|
|
* packet on reception of each duplicate
|
|
* ACK by increasing snd_cwnd by one
|
|
* segment. Restore the original
|
|
* snd_cwnd after packet transmission.
|
|
*/
|
|
cc_ack_received(tp, th, CC_DUPACK);
|
|
u_long oldcwnd = tp->snd_cwnd;
|
|
tcp_seq oldsndmax = tp->snd_max;
|
|
u_int sent;
|
|
int avail;
|
|
|
|
KASSERT(tp->t_dupacks == 1 ||
|
|
tp->t_dupacks == 2,
|
|
("%s: dupacks not 1 or 2",
|
|
__func__));
|
|
if (tp->t_dupacks == 1)
|
|
tp->snd_limited = 0;
|
|
tp->snd_cwnd =
|
|
(tp->snd_nxt - tp->snd_una) +
|
|
(tp->t_dupacks - tp->snd_limited) *
|
|
tp->t_maxseg;
|
|
/*
|
|
* Only call tcp_output when there
|
|
* is new data available to be sent.
|
|
* Otherwise we would send pure ACKs.
|
|
*/
|
|
SOCKBUF_LOCK(&so->so_snd);
|
|
avail = sbavail(&so->so_snd) -
|
|
(tp->snd_nxt - tp->snd_una);
|
|
SOCKBUF_UNLOCK(&so->so_snd);
|
|
if (avail > 0)
|
|
(void) tp->t_fb->tfb_tcp_output(tp);
|
|
sent = tp->snd_max - oldsndmax;
|
|
if (sent > tp->t_maxseg) {
|
|
KASSERT((tp->t_dupacks == 2 &&
|
|
tp->snd_limited == 0) ||
|
|
(sent == tp->t_maxseg + 1 &&
|
|
tp->t_flags & TF_SENTFIN),
|
|
("%s: sent too much",
|
|
__func__));
|
|
tp->snd_limited = 2;
|
|
} else if (sent > 0)
|
|
++tp->snd_limited;
|
|
tp->snd_cwnd = oldcwnd;
|
|
goto drop;
|
|
}
|
|
} else
|
|
tp->t_dupacks = 0;
|
|
break;
|
|
}
|
|
|
|
KASSERT(SEQ_GT(th->th_ack, tp->snd_una),
|
|
("%s: th_ack <= snd_una", __func__));
|
|
|
|
/*
|
|
* If the congestion window was inflated to account
|
|
* for the other side's cached packets, retract it.
|
|
*/
|
|
if (IN_FASTRECOVERY(tp->t_flags)) {
|
|
if (SEQ_LT(th->th_ack, tp->snd_recover)) {
|
|
if (tp->t_flags & TF_SACK_PERMIT)
|
|
tcp_sack_partialack(tp, th);
|
|
else
|
|
tcp_newreno_partial_ack(tp, th);
|
|
} else
|
|
cc_post_recovery(tp, th);
|
|
}
|
|
tp->t_dupacks = 0;
|
|
/*
|
|
* If we reach this point, ACK is not a duplicate,
|
|
* i.e., it ACKs something we sent.
|
|
*/
|
|
if (tp->t_flags & TF_NEEDSYN) {
|
|
/*
|
|
* T/TCP: Connection was half-synchronized, and our
|
|
* SYN has been ACK'd (so connection is now fully
|
|
* synchronized). Go to non-starred state,
|
|
* increment snd_una for ACK of SYN, and check if
|
|
* we can do window scaling.
|
|
*/
|
|
tp->t_flags &= ~TF_NEEDSYN;
|
|
tp->snd_una++;
|
|
/* Do window scaling? */
|
|
if ((tp->t_flags & (TF_RCVD_SCALE|TF_REQ_SCALE)) ==
|
|
(TF_RCVD_SCALE|TF_REQ_SCALE)) {
|
|
tp->rcv_scale = tp->request_r_scale;
|
|
/* Send window already scaled. */
|
|
}
|
|
}
|
|
|
|
process_ACK:
|
|
INP_WLOCK_ASSERT(tp->t_inpcb);
|
|
|
|
acked = BYTES_THIS_ACK(tp, th);
|
|
TCPSTAT_INC(tcps_rcvackpack);
|
|
TCPSTAT_ADD(tcps_rcvackbyte, acked);
|
|
|
|
/*
|
|
* If we just performed our first retransmit, and the ACK
|
|
* arrives within our recovery window, then it was a mistake
|
|
* to do the retransmit in the first place. Recover our
|
|
* original cwnd and ssthresh, and proceed to transmit where
|
|
* we left off.
|
|
*/
|
|
if (tp->t_rxtshift == 1 && tp->t_flags & TF_PREVVALID &&
|
|
(int)(ticks - tp->t_badrxtwin) < 0)
|
|
cc_cong_signal(tp, th, CC_RTO_ERR);
|
|
|
|
/*
|
|
* If we have a timestamp reply, update smoothed
|
|
* round trip time. If no timestamp is present but
|
|
* transmit timer is running and timed sequence
|
|
* number was acked, update smoothed round trip time.
|
|
* Since we now have an rtt measurement, cancel the
|
|
* timer backoff (cf., Phil Karn's retransmit alg.).
|
|
* Recompute the initial retransmit timer.
|
|
*
|
|
* Some boxes send broken timestamp replies
|
|
* during the SYN+ACK phase, ignore
|
|
* timestamps of 0 or we could calculate a
|
|
* huge RTT and blow up the retransmit timer.
|
|
*/
|
|
if ((to->to_flags & TOF_TS) != 0 && to->to_tsecr) {
|
|
u_int t;
|
|
|
|
t = tcp_ts_getticks() - to->to_tsecr;
|
|
if (!tp->t_rttlow || tp->t_rttlow > t)
|
|
tp->t_rttlow = t;
|
|
tcp_xmit_timer(tp, TCP_TS_TO_TICKS(t) + 1);
|
|
} else if (tp->t_rtttime && SEQ_GT(th->th_ack, tp->t_rtseq)) {
|
|
if (!tp->t_rttlow || tp->t_rttlow > ticks - tp->t_rtttime)
|
|
tp->t_rttlow = ticks - tp->t_rtttime;
|
|
tcp_xmit_timer(tp, ticks - tp->t_rtttime);
|
|
}
|
|
|
|
/*
|
|
* If all outstanding data is acked, stop retransmit
|
|
* timer and remember to restart (more output or persist).
|
|
* If there is more data to be acked, restart retransmit
|
|
* timer, using current (possibly backed-off) value.
|
|
*/
|
|
if (th->th_ack == tp->snd_max) {
|
|
tcp_timer_activate(tp, TT_REXMT, 0);
|
|
needoutput = 1;
|
|
} else if (!tcp_timer_active(tp, TT_PERSIST))
|
|
tcp_timer_activate(tp, TT_REXMT, tp->t_rxtcur);
|
|
|
|
/*
|
|
* If no data (only SYN) was ACK'd,
|
|
* skip rest of ACK processing.
|
|
*/
|
|
if (acked == 0)
|
|
goto step6;
|
|
|
|
/*
|
|
* Let the congestion control algorithm update congestion
|
|
* control related information. This typically means increasing
|
|
* the congestion window.
|
|
*/
|
|
cc_ack_received(tp, th, CC_ACK);
|
|
|
|
SOCKBUF_LOCK(&so->so_snd);
|
|
if (acked > sbavail(&so->so_snd)) {
|
|
tp->snd_wnd -= sbavail(&so->so_snd);
|
|
mfree = sbcut_locked(&so->so_snd,
|
|
(int)sbavail(&so->so_snd));
|
|
ourfinisacked = 1;
|
|
} else {
|
|
mfree = sbcut_locked(&so->so_snd, acked);
|
|
tp->snd_wnd -= acked;
|
|
ourfinisacked = 0;
|
|
}
|
|
/* NB: sowwakeup_locked() does an implicit unlock. */
|
|
sowwakeup_locked(so);
|
|
m_freem(mfree);
|
|
/* Detect una wraparound. */
|
|
if (!IN_RECOVERY(tp->t_flags) &&
|
|
SEQ_GT(tp->snd_una, tp->snd_recover) &&
|
|
SEQ_LEQ(th->th_ack, tp->snd_recover))
|
|
tp->snd_recover = th->th_ack - 1;
|
|
/* XXXLAS: Can this be moved up into cc_post_recovery? */
|
|
if (IN_RECOVERY(tp->t_flags) &&
|
|
SEQ_GEQ(th->th_ack, tp->snd_recover)) {
|
|
EXIT_RECOVERY(tp->t_flags);
|
|
}
|
|
tp->snd_una = th->th_ack;
|
|
if (tp->t_flags & TF_SACK_PERMIT) {
|
|
if (SEQ_GT(tp->snd_una, tp->snd_recover))
|
|
tp->snd_recover = tp->snd_una;
|
|
}
|
|
if (SEQ_LT(tp->snd_nxt, tp->snd_una))
|
|
tp->snd_nxt = tp->snd_una;
|
|
|
|
switch (tp->t_state) {
|
|
|
|
/*
|
|
* In FIN_WAIT_1 STATE in addition to the processing
|
|
* for the ESTABLISHED state if our FIN is now acknowledged
|
|
* then enter FIN_WAIT_2.
|
|
*/
|
|
case TCPS_FIN_WAIT_1:
|
|
if (ourfinisacked) {
|
|
/*
|
|
* If we can't receive any more
|
|
* data, then closing user can proceed.
|
|
* Starting the timer is contrary to the
|
|
* specification, but if we don't get a FIN
|
|
* we'll hang forever.
|
|
*
|
|
* XXXjl:
|
|
* we should release the tp also, and use a
|
|
* compressed state.
|
|
*/
|
|
if (so->so_rcv.sb_state & SBS_CANTRCVMORE) {
|
|
soisdisconnected(so);
|
|
tcp_timer_activate(tp, TT_2MSL,
|
|
(tcp_fast_finwait2_recycle ?
|
|
tcp_finwait2_timeout :
|
|
TP_MAXIDLE(tp)));
|
|
}
|
|
tcp_state_change(tp, TCPS_FIN_WAIT_2);
|
|
}
|
|
break;
|
|
|
|
/*
|
|
* In CLOSING STATE in addition to the processing for
|
|
* the ESTABLISHED state if the ACK acknowledges our FIN
|
|
* then enter the TIME-WAIT state, otherwise ignore
|
|
* the segment.
|
|
*/
|
|
case TCPS_CLOSING:
|
|
if (ourfinisacked) {
|
|
INP_INFO_RLOCK_ASSERT(&V_tcbinfo);
|
|
tcp_twstart(tp);
|
|
INP_INFO_RUNLOCK(&V_tcbinfo);
|
|
m_freem(m);
|
|
return;
|
|
}
|
|
break;
|
|
|
|
/*
|
|
* In LAST_ACK, we may still be waiting for data to drain
|
|
* and/or to be acked, as well as for the ack of our FIN.
|
|
* If our FIN is now acknowledged, delete the TCB,
|
|
* enter the closed state and return.
|
|
*/
|
|
case TCPS_LAST_ACK:
|
|
if (ourfinisacked) {
|
|
INP_INFO_RLOCK_ASSERT(&V_tcbinfo);
|
|
tp = tcp_close(tp);
|
|
goto drop;
|
|
}
|
|
break;
|
|
}
|
|
}
|
|
|
|
step6:
|
|
INP_WLOCK_ASSERT(tp->t_inpcb);
|
|
|
|
/*
|
|
* Update window information.
|
|
* Don't look at window if no ACK: TAC's send garbage on first SYN.
|
|
*/
|
|
if ((thflags & TH_ACK) &&
|
|
(SEQ_LT(tp->snd_wl1, th->th_seq) ||
|
|
(tp->snd_wl1 == th->th_seq && (SEQ_LT(tp->snd_wl2, th->th_ack) ||
|
|
(tp->snd_wl2 == th->th_ack && tiwin > tp->snd_wnd))))) {
|
|
/* keep track of pure window updates */
|
|
if (tlen == 0 &&
|
|
tp->snd_wl2 == th->th_ack && tiwin > tp->snd_wnd)
|
|
TCPSTAT_INC(tcps_rcvwinupd);
|
|
tp->snd_wnd = tiwin;
|
|
tp->snd_wl1 = th->th_seq;
|
|
tp->snd_wl2 = th->th_ack;
|
|
if (tp->snd_wnd > tp->max_sndwnd)
|
|
tp->max_sndwnd = tp->snd_wnd;
|
|
needoutput = 1;
|
|
}
|
|
|
|
/*
|
|
* Process segments with URG.
|
|
*/
|
|
if ((thflags & TH_URG) && th->th_urp &&
|
|
TCPS_HAVERCVDFIN(tp->t_state) == 0) {
|
|
/*
|
|
* This is a kludge, but if we receive and accept
|
|
* random urgent pointers, we'll crash in
|
|
* soreceive. It's hard to imagine someone
|
|
* actually wanting to send this much urgent data.
|
|
*/
|
|
SOCKBUF_LOCK(&so->so_rcv);
|
|
if (th->th_urp + sbavail(&so->so_rcv) > sb_max) {
|
|
th->th_urp = 0; /* XXX */
|
|
thflags &= ~TH_URG; /* XXX */
|
|
SOCKBUF_UNLOCK(&so->so_rcv); /* XXX */
|
|
goto dodata; /* XXX */
|
|
}
|
|
/*
|
|
* If this segment advances the known urgent pointer,
|
|
* then mark the data stream. This should not happen
|
|
* in CLOSE_WAIT, CLOSING, LAST_ACK or TIME_WAIT STATES since
|
|
* a FIN has been received from the remote side.
|
|
* In these states we ignore the URG.
|
|
*
|
|
* According to RFC961 (Assigned Protocols),
|
|
* the urgent pointer points to the last octet
|
|
* of urgent data. We continue, however,
|
|
* to consider it to indicate the first octet
|
|
* of data past the urgent section as the original
|
|
* spec states (in one of two places).
|
|
*/
|
|
if (SEQ_GT(th->th_seq+th->th_urp, tp->rcv_up)) {
|
|
tp->rcv_up = th->th_seq + th->th_urp;
|
|
so->so_oobmark = sbavail(&so->so_rcv) +
|
|
(tp->rcv_up - tp->rcv_nxt) - 1;
|
|
if (so->so_oobmark == 0)
|
|
so->so_rcv.sb_state |= SBS_RCVATMARK;
|
|
sohasoutofband(so);
|
|
tp->t_oobflags &= ~(TCPOOB_HAVEDATA | TCPOOB_HADDATA);
|
|
}
|
|
SOCKBUF_UNLOCK(&so->so_rcv);
|
|
/*
|
|
* Remove out of band data so doesn't get presented to user.
|
|
* This can happen independent of advancing the URG pointer,
|
|
* but if two URG's are pending at once, some out-of-band
|
|
* data may creep in... ick.
|
|
*/
|
|
if (th->th_urp <= (u_long)tlen &&
|
|
!(so->so_options & SO_OOBINLINE)) {
|
|
/* hdr drop is delayed */
|
|
tcp_pulloutofband(so, th, m, drop_hdrlen);
|
|
}
|
|
} else {
|
|
/*
|
|
* If no out of band data is expected,
|
|
* pull receive urgent pointer along
|
|
* with the receive window.
|
|
*/
|
|
if (SEQ_GT(tp->rcv_nxt, tp->rcv_up))
|
|
tp->rcv_up = tp->rcv_nxt;
|
|
}
|
|
dodata: /* XXX */
|
|
INP_WLOCK_ASSERT(tp->t_inpcb);
|
|
|
|
/*
|
|
* Process the segment text, merging it into the TCP sequencing queue,
|
|
* and arranging for acknowledgment of receipt if necessary.
|
|
* This process logically involves adjusting tp->rcv_wnd as data
|
|
* is presented to the user (this happens in tcp_usrreq.c,
|
|
* case PRU_RCVD). If a FIN has already been received on this
|
|
* connection then we just ignore the text.
|
|
*/
|
|
if ((tlen || (thflags & TH_FIN)) &&
|
|
TCPS_HAVERCVDFIN(tp->t_state) == 0) {
|
|
tcp_seq save_start = th->th_seq;
|
|
m_adj(m, drop_hdrlen); /* delayed header drop */
|
|
/*
|
|
* Insert segment which includes th into TCP reassembly queue
|
|
* with control block tp. Set thflags to whether reassembly now
|
|
* includes a segment with FIN. This handles the common case
|
|
* inline (segment is the next to be received on an established
|
|
* connection, and the queue is empty), avoiding linkage into
|
|
* and removal from the queue and repetition of various
|
|
* conversions.
|
|
* Set DELACK for segments received in order, but ack
|
|
* immediately when segments are out of order (so
|
|
* fast retransmit can work).
|
|
*/
|
|
if (th->th_seq == tp->rcv_nxt &&
|
|
LIST_EMPTY(&tp->t_segq) &&
|
|
TCPS_HAVEESTABLISHED(tp->t_state)) {
|
|
if (DELAY_ACK(tp, tlen))
|
|
tp->t_flags |= TF_DELACK;
|
|
else
|
|
tp->t_flags |= TF_ACKNOW;
|
|
tp->rcv_nxt += tlen;
|
|
thflags = th->th_flags & TH_FIN;
|
|
TCPSTAT_INC(tcps_rcvpack);
|
|
TCPSTAT_ADD(tcps_rcvbyte, tlen);
|
|
SOCKBUF_LOCK(&so->so_rcv);
|
|
if (so->so_rcv.sb_state & SBS_CANTRCVMORE)
|
|
m_freem(m);
|
|
else
|
|
sbappendstream_locked(&so->so_rcv, m, 0);
|
|
/* NB: sorwakeup_locked() does an implicit unlock. */
|
|
sorwakeup_locked(so);
|
|
} else {
|
|
/*
|
|
* XXX: Due to the header drop above "th" is
|
|
* theoretically invalid by now. Fortunately
|
|
* m_adj() doesn't actually frees any mbufs
|
|
* when trimming from the head.
|
|
*/
|
|
thflags = tcp_reass(tp, th, &tlen, m);
|
|
tp->t_flags |= TF_ACKNOW;
|
|
}
|
|
if (tlen > 0 && (tp->t_flags & TF_SACK_PERMIT))
|
|
tcp_update_sack_list(tp, save_start, save_start + tlen);
|
|
#if 0
|
|
/*
|
|
* Note the amount of data that peer has sent into
|
|
* our window, in order to estimate the sender's
|
|
* buffer size.
|
|
* XXX: Unused.
|
|
*/
|
|
if (SEQ_GT(tp->rcv_adv, tp->rcv_nxt))
|
|
len = so->so_rcv.sb_hiwat - (tp->rcv_adv - tp->rcv_nxt);
|
|
else
|
|
len = so->so_rcv.sb_hiwat;
|
|
#endif
|
|
} else {
|
|
m_freem(m);
|
|
thflags &= ~TH_FIN;
|
|
}
|
|
|
|
/*
|
|
* If FIN is received ACK the FIN and let the user know
|
|
* that the connection is closing.
|
|
*/
|
|
if (thflags & TH_FIN) {
|
|
if (TCPS_HAVERCVDFIN(tp->t_state) == 0) {
|
|
socantrcvmore(so);
|
|
/*
|
|
* If connection is half-synchronized
|
|
* (ie NEEDSYN flag on) then delay ACK,
|
|
* so it may be piggybacked when SYN is sent.
|
|
* Otherwise, since we received a FIN then no
|
|
* more input can be expected, send ACK now.
|
|
*/
|
|
if (tp->t_flags & TF_NEEDSYN)
|
|
tp->t_flags |= TF_DELACK;
|
|
else
|
|
tp->t_flags |= TF_ACKNOW;
|
|
tp->rcv_nxt++;
|
|
}
|
|
switch (tp->t_state) {
|
|
|
|
/*
|
|
* In SYN_RECEIVED and ESTABLISHED STATES
|
|
* enter the CLOSE_WAIT state.
|
|
*/
|
|
case TCPS_SYN_RECEIVED:
|
|
tp->t_starttime = ticks;
|
|
/* FALLTHROUGH */
|
|
case TCPS_ESTABLISHED:
|
|
tcp_state_change(tp, TCPS_CLOSE_WAIT);
|
|
break;
|
|
|
|
/*
|
|
* If still in FIN_WAIT_1 STATE FIN has not been acked so
|
|
* enter the CLOSING state.
|
|
*/
|
|
case TCPS_FIN_WAIT_1:
|
|
tcp_state_change(tp, TCPS_CLOSING);
|
|
break;
|
|
|
|
/*
|
|
* In FIN_WAIT_2 state enter the TIME_WAIT state,
|
|
* starting the time-wait timer, turning off the other
|
|
* standard timers.
|
|
*/
|
|
case TCPS_FIN_WAIT_2:
|
|
INP_INFO_RLOCK_ASSERT(&V_tcbinfo);
|
|
KASSERT(ti_locked == TI_RLOCKED, ("%s: dodata "
|
|
"TCP_FIN_WAIT_2 ti_locked: %d", __func__,
|
|
ti_locked));
|
|
|
|
tcp_twstart(tp);
|
|
INP_INFO_RUNLOCK(&V_tcbinfo);
|
|
return;
|
|
}
|
|
}
|
|
if (ti_locked == TI_RLOCKED) {
|
|
INP_INFO_RUNLOCK(&V_tcbinfo);
|
|
}
|
|
ti_locked = TI_UNLOCKED;
|
|
|
|
#ifdef TCPDEBUG
|
|
if (so->so_options & SO_DEBUG)
|
|
tcp_trace(TA_INPUT, ostate, tp, (void *)tcp_saveipgen,
|
|
&tcp_savetcp, 0);
|
|
#endif
|
|
TCP_PROBE3(debug__input, tp, th, mtod(m, const char *));
|
|
|
|
/*
|
|
* Return any desired output.
|
|
*/
|
|
if (needoutput || (tp->t_flags & TF_ACKNOW))
|
|
(void) tp->t_fb->tfb_tcp_output(tp);
|
|
|
|
KASSERT(ti_locked == TI_UNLOCKED, ("%s: check_delack ti_locked %d",
|
|
__func__, ti_locked));
|
|
INP_INFO_UNLOCK_ASSERT(&V_tcbinfo);
|
|
INP_WLOCK_ASSERT(tp->t_inpcb);
|
|
|
|
if (tp->t_flags & TF_DELACK) {
|
|
tp->t_flags &= ~TF_DELACK;
|
|
tcp_timer_activate(tp, TT_DELACK, tcp_delacktime);
|
|
}
|
|
INP_WUNLOCK(tp->t_inpcb);
|
|
return;
|
|
|
|
dropafterack:
|
|
/*
|
|
* Generate an ACK dropping incoming segment if it occupies
|
|
* sequence space, where the ACK reflects our state.
|
|
*
|
|
* We can now skip the test for the RST flag since all
|
|
* paths to this code happen after packets containing
|
|
* RST have been dropped.
|
|
*
|
|
* In the SYN-RECEIVED state, don't send an ACK unless the
|
|
* segment we received passes the SYN-RECEIVED ACK test.
|
|
* If it fails send a RST. This breaks the loop in the
|
|
* "LAND" DoS attack, and also prevents an ACK storm
|
|
* between two listening ports that have been sent forged
|
|
* SYN segments, each with the source address of the other.
|
|
*/
|
|
if (tp->t_state == TCPS_SYN_RECEIVED && (thflags & TH_ACK) &&
|
|
(SEQ_GT(tp->snd_una, th->th_ack) ||
|
|
SEQ_GT(th->th_ack, tp->snd_max)) ) {
|
|
rstreason = BANDLIM_RST_OPENPORT;
|
|
goto dropwithreset;
|
|
}
|
|
#ifdef TCPDEBUG
|
|
if (so->so_options & SO_DEBUG)
|
|
tcp_trace(TA_DROP, ostate, tp, (void *)tcp_saveipgen,
|
|
&tcp_savetcp, 0);
|
|
#endif
|
|
TCP_PROBE3(debug__input, tp, th, mtod(m, const char *));
|
|
if (ti_locked == TI_RLOCKED) {
|
|
INP_INFO_RUNLOCK(&V_tcbinfo);
|
|
}
|
|
ti_locked = TI_UNLOCKED;
|
|
|
|
tp->t_flags |= TF_ACKNOW;
|
|
(void) tp->t_fb->tfb_tcp_output(tp);
|
|
INP_WUNLOCK(tp->t_inpcb);
|
|
m_freem(m);
|
|
return;
|
|
|
|
dropwithreset:
|
|
if (ti_locked == TI_RLOCKED) {
|
|
INP_INFO_RUNLOCK(&V_tcbinfo);
|
|
}
|
|
ti_locked = TI_UNLOCKED;
|
|
|
|
if (tp != NULL) {
|
|
tcp_dropwithreset(m, th, tp, tlen, rstreason);
|
|
INP_WUNLOCK(tp->t_inpcb);
|
|
} else
|
|
tcp_dropwithreset(m, th, NULL, tlen, rstreason);
|
|
return;
|
|
|
|
drop:
|
|
if (ti_locked == TI_RLOCKED) {
|
|
INP_INFO_RUNLOCK(&V_tcbinfo);
|
|
ti_locked = TI_UNLOCKED;
|
|
}
|
|
#ifdef INVARIANTS
|
|
else
|
|
INP_INFO_UNLOCK_ASSERT(&V_tcbinfo);
|
|
#endif
|
|
|
|
/*
|
|
* Drop space held by incoming segment and return.
|
|
*/
|
|
#ifdef TCPDEBUG
|
|
if (tp == NULL || (tp->t_inpcb->inp_socket->so_options & SO_DEBUG))
|
|
tcp_trace(TA_DROP, ostate, tp, (void *)tcp_saveipgen,
|
|
&tcp_savetcp, 0);
|
|
#endif
|
|
TCP_PROBE3(debug__input, tp, th, mtod(m, const char *));
|
|
if (tp != NULL)
|
|
INP_WUNLOCK(tp->t_inpcb);
|
|
m_freem(m);
|
|
}
|
|
|
|
|
|
/*
|
|
* Do fast slow is a combination of the original
|
|
* tcp_dosegment and a split fastpath, one function
|
|
* for the fast-ack which also includes allowing fastpath
|
|
* for window advanced in sequence acks. And also a
|
|
* sub-function that handles the insequence data.
|
|
*/
|
|
void
|
|
tcp_do_segment_fastslow(struct mbuf *m, struct tcphdr *th, struct socket *so,
|
|
struct tcpcb *tp, int drop_hdrlen, int tlen, uint8_t iptos,
|
|
int ti_locked)
|
|
{
|
|
int thflags;
|
|
u_long tiwin;
|
|
char *s;
|
|
int can_enter;
|
|
struct in_conninfo *inc;
|
|
struct tcpopt to;
|
|
|
|
thflags = th->th_flags;
|
|
tp->sackhint.last_sack_ack = 0;
|
|
inc = &tp->t_inpcb->inp_inc;
|
|
/*
|
|
* If this is either a state-changing packet or current state isn't
|
|
* established, we require a write lock on tcbinfo. Otherwise, we
|
|
* allow the tcbinfo to be in either alocked or unlocked, as the
|
|
* caller may have unnecessarily acquired a write lock due to a race.
|
|
*/
|
|
if ((thflags & (TH_SYN | TH_FIN | TH_RST)) != 0 ||
|
|
tp->t_state != TCPS_ESTABLISHED) {
|
|
KASSERT(ti_locked == TI_RLOCKED, ("%s ti_locked %d for "
|
|
"SYN/FIN/RST/!EST", __func__, ti_locked));
|
|
INP_INFO_RLOCK_ASSERT(&V_tcbinfo);
|
|
} else {
|
|
#ifdef INVARIANTS
|
|
if (ti_locked == TI_RLOCKED) {
|
|
INP_INFO_RLOCK_ASSERT(&V_tcbinfo);
|
|
} else {
|
|
KASSERT(ti_locked == TI_UNLOCKED, ("%s: EST "
|
|
"ti_locked: %d", __func__, ti_locked));
|
|
INP_INFO_UNLOCK_ASSERT(&V_tcbinfo);
|
|
}
|
|
#endif
|
|
}
|
|
INP_WLOCK_ASSERT(tp->t_inpcb);
|
|
KASSERT(tp->t_state > TCPS_LISTEN, ("%s: TCPS_LISTEN",
|
|
__func__));
|
|
KASSERT(tp->t_state != TCPS_TIME_WAIT, ("%s: TCPS_TIME_WAIT",
|
|
__func__));
|
|
|
|
/*
|
|
* Segment received on connection.
|
|
* Reset idle time and keep-alive timer.
|
|
* XXX: This should be done after segment
|
|
* validation to ignore broken/spoofed segs.
|
|
*/
|
|
tp->t_rcvtime = ticks;
|
|
if (TCPS_HAVEESTABLISHED(tp->t_state))
|
|
tcp_timer_activate(tp, TT_KEEP, TP_KEEPIDLE(tp));
|
|
|
|
/*
|
|
* Unscale the window into a 32-bit value.
|
|
* For the SYN_SENT state the scale is zero.
|
|
*/
|
|
tiwin = th->th_win << tp->snd_scale;
|
|
|
|
/*
|
|
* TCP ECN processing.
|
|
*/
|
|
if (tp->t_flags & TF_ECN_PERMIT) {
|
|
if (thflags & TH_CWR)
|
|
tp->t_flags &= ~TF_ECN_SND_ECE;
|
|
switch (iptos & IPTOS_ECN_MASK) {
|
|
case IPTOS_ECN_CE:
|
|
tp->t_flags |= TF_ECN_SND_ECE;
|
|
TCPSTAT_INC(tcps_ecn_ce);
|
|
break;
|
|
case IPTOS_ECN_ECT0:
|
|
TCPSTAT_INC(tcps_ecn_ect0);
|
|
break;
|
|
case IPTOS_ECN_ECT1:
|
|
TCPSTAT_INC(tcps_ecn_ect1);
|
|
break;
|
|
}
|
|
/* Congestion experienced. */
|
|
if (thflags & TH_ECE) {
|
|
cc_cong_signal(tp, th, CC_ECN);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Parse options on any incoming segment.
|
|
*/
|
|
tcp_dooptions(&to, (u_char *)(th + 1),
|
|
(th->th_off << 2) - sizeof(struct tcphdr),
|
|
(thflags & TH_SYN) ? TO_SYN : 0);
|
|
|
|
/*
|
|
* If echoed timestamp is later than the current time,
|
|
* fall back to non RFC1323 RTT calculation. Normalize
|
|
* timestamp if syncookies were used when this connection
|
|
* was established.
|
|
*/
|
|
if ((to.to_flags & TOF_TS) && (to.to_tsecr != 0)) {
|
|
to.to_tsecr -= tp->ts_offset;
|
|
if (TSTMP_GT(to.to_tsecr, tcp_ts_getticks()))
|
|
to.to_tsecr = 0;
|
|
}
|
|
/*
|
|
* If timestamps were negotiated during SYN/ACK they should
|
|
* appear on every segment during this session and vice versa.
|
|
*/
|
|
if ((tp->t_flags & TF_RCVD_TSTMP) && !(to.to_flags & TOF_TS)) {
|
|
if ((s = tcp_log_addrs(inc, th, NULL, NULL))) {
|
|
log(LOG_DEBUG, "%s; %s: Timestamp missing, "
|
|
"no action\n", s, __func__);
|
|
free(s, M_TCPLOG);
|
|
}
|
|
}
|
|
if (!(tp->t_flags & TF_RCVD_TSTMP) && (to.to_flags & TOF_TS)) {
|
|
if ((s = tcp_log_addrs(inc, th, NULL, NULL))) {
|
|
log(LOG_DEBUG, "%s; %s: Timestamp not expected, "
|
|
"no action\n", s, __func__);
|
|
free(s, M_TCPLOG);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Process options only when we get SYN/ACK back. The SYN case
|
|
* for incoming connections is handled in tcp_syncache.
|
|
* According to RFC1323 the window field in a SYN (i.e., a <SYN>
|
|
* or <SYN,ACK>) segment itself is never scaled.
|
|
* XXX this is traditional behavior, may need to be cleaned up.
|
|
*/
|
|
if (tp->t_state == TCPS_SYN_SENT && (thflags & TH_SYN)) {
|
|
if ((to.to_flags & TOF_SCALE) &&
|
|
(tp->t_flags & TF_REQ_SCALE)) {
|
|
tp->t_flags |= TF_RCVD_SCALE;
|
|
tp->snd_scale = to.to_wscale;
|
|
}
|
|
/*
|
|
* Initial send window. It will be updated with
|
|
* the next incoming segment to the scaled value.
|
|
*/
|
|
tp->snd_wnd = th->th_win;
|
|
if (to.to_flags & TOF_TS) {
|
|
tp->t_flags |= TF_RCVD_TSTMP;
|
|
tp->ts_recent = to.to_tsval;
|
|
tp->ts_recent_age = tcp_ts_getticks();
|
|
}
|
|
if (to.to_flags & TOF_MSS)
|
|
tcp_mss(tp, to.to_mss);
|
|
if ((tp->t_flags & TF_SACK_PERMIT) &&
|
|
(to.to_flags & TOF_SACKPERM) == 0)
|
|
tp->t_flags &= ~TF_SACK_PERMIT;
|
|
}
|
|
can_enter = 0;
|
|
if (__predict_true((tlen == 0))) {
|
|
/*
|
|
* The ack moved forward and we have a window (non-zero)
|
|
* <or>
|
|
* The ack did not move forward, but the window increased.
|
|
*/
|
|
if (__predict_true((SEQ_GT(th->th_ack, tp->snd_una) && tiwin) ||
|
|
((th->th_ack == tp->snd_una) && tiwin && (tiwin > tp->snd_wnd)))) {
|
|
can_enter = 1;
|
|
}
|
|
} else {
|
|
/*
|
|
* Data incoming, use the old entry criteria
|
|
* for fast-path with data.
|
|
*/
|
|
if ((tiwin && tiwin == tp->snd_wnd)) {
|
|
can_enter = 1;
|
|
}
|
|
}
|
|
/*
|
|
* Header prediction: check for the two common cases
|
|
* of a uni-directional data xfer. If the packet has
|
|
* no control flags, is in-sequence, the window didn't
|
|
* change and we're not retransmitting, it's a
|
|
* candidate. If the length is zero and the ack moved
|
|
* forward, we're the sender side of the xfer. Just
|
|
* free the data acked & wake any higher level process
|
|
* that was blocked waiting for space. If the length
|
|
* is non-zero and the ack didn't move, we're the
|
|
* receiver side. If we're getting packets in-order
|
|
* (the reassembly queue is empty), add the data to
|
|
* the socket buffer and note that we need a delayed ack.
|
|
* Make sure that the hidden state-flags are also off.
|
|
* Since we check for TCPS_ESTABLISHED first, it can only
|
|
* be TH_NEEDSYN.
|
|
*/
|
|
if (__predict_true(tp->t_state == TCPS_ESTABLISHED &&
|
|
th->th_seq == tp->rcv_nxt &&
|
|
(thflags & (TH_SYN|TH_FIN|TH_RST|TH_URG|TH_ACK)) == TH_ACK &&
|
|
tp->snd_nxt == tp->snd_max &&
|
|
can_enter &&
|
|
((tp->t_flags & (TF_NEEDSYN|TF_NEEDFIN)) == 0) &&
|
|
LIST_EMPTY(&tp->t_segq) &&
|
|
((to.to_flags & TOF_TS) == 0 ||
|
|
TSTMP_GEQ(to.to_tsval, tp->ts_recent)))) {
|
|
if (__predict_true((tlen == 0) &&
|
|
(SEQ_LEQ(th->th_ack, tp->snd_max) &&
|
|
!IN_RECOVERY(tp->t_flags) &&
|
|
(to.to_flags & TOF_SACK) == 0 &&
|
|
TAILQ_EMPTY(&tp->snd_holes)))) {
|
|
/* We are done */
|
|
tcp_do_fastack(m, th, so, tp, &to, drop_hdrlen, tlen,
|
|
ti_locked, tiwin);
|
|
return;
|
|
} else if ((tlen) &&
|
|
(th->th_ack == tp->snd_una &&
|
|
tlen <= sbspace(&so->so_rcv))) {
|
|
tcp_do_fastnewdata(m, th, so, tp, &to, drop_hdrlen, tlen,
|
|
ti_locked, tiwin);
|
|
/* We are done */
|
|
return;
|
|
}
|
|
}
|
|
tcp_do_slowpath(m, th, so, tp, &to, drop_hdrlen, tlen,
|
|
ti_locked, tiwin, thflags);
|
|
}
|
|
|
|
|
|
/*
|
|
* This subfunction is used to try to highly optimize the
|
|
* fast path. We again allow window updates that are
|
|
* in sequence to remain in the fast-path. We also add
|
|
* in the __predict's to attempt to help the compiler.
|
|
* Note that if we return a 0, then we can *not* process
|
|
* it and the caller should push the packet into the
|
|
* slow-path.
|
|
*/
|
|
static int
|
|
tcp_fastack(struct mbuf *m, struct tcphdr *th, struct socket *so,
|
|
struct tcpcb *tp, struct tcpopt *to, int drop_hdrlen, int tlen,
|
|
int ti_locked, u_long tiwin)
|
|
{
|
|
int acked;
|
|
int winup_only=0;
|
|
#ifdef TCPDEBUG
|
|
/*
|
|
* The size of tcp_saveipgen must be the size of the max ip header,
|
|
* now IPv6.
|
|
*/
|
|
u_char tcp_saveipgen[IP6_HDR_LEN];
|
|
struct tcphdr tcp_savetcp;
|
|
short ostate = 0;
|
|
#endif
|
|
|
|
|
|
if (__predict_false(SEQ_LEQ(th->th_ack, tp->snd_una))) {
|
|
/* Old ack, behind (or duplicate to) the last one rcv'd */
|
|
return (0);
|
|
}
|
|
if (__predict_false(th->th_ack == tp->snd_una) &&
|
|
__predict_false(tiwin <= tp->snd_wnd)) {
|
|
/* duplicate ack <or> a shrinking dup ack with shrinking window */
|
|
return (0);
|
|
}
|
|
if (__predict_false(tiwin == 0)) {
|
|
/* zero window */
|
|
return (0);
|
|
}
|
|
if (__predict_false(SEQ_GT(th->th_ack, tp->snd_max))) {
|
|
/* Above what we have sent? */
|
|
return (0);
|
|
}
|
|
if (__predict_false(tp->snd_nxt != tp->snd_max)) {
|
|
/* We are retransmitting */
|
|
return (0);
|
|
}
|
|
if (__predict_false(tp->t_flags & (TF_NEEDSYN|TF_NEEDFIN))) {
|
|
/* We need a SYN or a FIN, unlikely.. */
|
|
return (0);
|
|
}
|
|
if((to->to_flags & TOF_TS) && __predict_false(TSTMP_LT(to->to_tsval, tp->ts_recent))) {
|
|
/* Timestamp is behind .. old ack with seq wrap? */
|
|
return (0);
|
|
}
|
|
if (__predict_false(IN_RECOVERY(tp->t_flags))) {
|
|
/* Still recovering */
|
|
return (0);
|
|
}
|
|
if (__predict_false(to->to_flags & TOF_SACK)) {
|
|
/* Sack included in the ack.. */
|
|
return (0);
|
|
}
|
|
if (!TAILQ_EMPTY(&tp->snd_holes)) {
|
|
/* We have sack holes on our scoreboard */
|
|
return (0);
|
|
}
|
|
/* Ok if we reach here, we can process a fast-ack */
|
|
|
|
/* Did the window get updated? */
|
|
if (tiwin != tp->snd_wnd) {
|
|
/* keep track of pure window updates */
|
|
if (tp->snd_wl2 == th->th_ack && tiwin > tp->snd_wnd) {
|
|
winup_only = 1;
|
|
TCPSTAT_INC(tcps_rcvwinupd);
|
|
}
|
|
tp->snd_wnd = tiwin;
|
|
tp->snd_wl1 = th->th_seq;
|
|
if (tp->snd_wnd > tp->max_sndwnd)
|
|
tp->max_sndwnd = tp->snd_wnd;
|
|
}
|
|
/*
|
|
* Pull snd_wl2 up to prevent seq wrap relative
|
|
* to th_ack.
|
|
*/
|
|
tp->snd_wl2 = th->th_ack;
|
|
/*
|
|
* If last ACK falls within this segment's sequence numbers,
|
|
* record the timestamp.
|
|
* NOTE that the test is modified according to the latest
|
|
* proposal of the tcplw@cray.com list (Braden 1993/04/26).
|
|
*/
|
|
if ((to->to_flags & TOF_TS) != 0 &&
|
|
SEQ_LEQ(th->th_seq, tp->last_ack_sent)) {
|
|
tp->ts_recent_age = tcp_ts_getticks();
|
|
tp->ts_recent = to->to_tsval;
|
|
}
|
|
/*
|
|
* This is a pure ack for outstanding data.
|
|
*/
|
|
if (ti_locked == TI_RLOCKED) {
|
|
INP_INFO_RUNLOCK(&V_tcbinfo);
|
|
}
|
|
ti_locked = TI_UNLOCKED;
|
|
|
|
TCPSTAT_INC(tcps_predack);
|
|
|
|
/*
|
|
* "bad retransmit" recovery.
|
|
*/
|
|
if (tp->t_rxtshift == 1 &&
|
|
tp->t_flags & TF_PREVVALID &&
|
|
(int)(ticks - tp->t_badrxtwin) < 0) {
|
|
cc_cong_signal(tp, th, CC_RTO_ERR);
|
|
}
|
|
|
|
/*
|
|
* Recalculate the transmit timer / rtt.
|
|
*
|
|
* Some boxes send broken timestamp replies
|
|
* during the SYN+ACK phase, ignore
|
|
* timestamps of 0 or we could calculate a
|
|
* huge RTT and blow up the retransmit timer.
|
|
*/
|
|
if ((to->to_flags & TOF_TS) != 0 &&
|
|
to->to_tsecr) {
|
|
u_int t;
|
|
|
|
t = tcp_ts_getticks() - to->to_tsecr;
|
|
if (!tp->t_rttlow || tp->t_rttlow > t)
|
|
tp->t_rttlow = t;
|
|
tcp_xmit_timer(tp,
|
|
TCP_TS_TO_TICKS(t) + 1);
|
|
} else if (tp->t_rtttime &&
|
|
SEQ_GT(th->th_ack, tp->t_rtseq)) {
|
|
if (!tp->t_rttlow ||
|
|
tp->t_rttlow > ticks - tp->t_rtttime)
|
|
tp->t_rttlow = ticks - tp->t_rtttime;
|
|
tcp_xmit_timer(tp,
|
|
ticks - tp->t_rtttime);
|
|
}
|
|
if (winup_only == 0) {
|
|
acked = BYTES_THIS_ACK(tp, th);
|
|
|
|
/* Run HHOOK_TCP_ESTABLISHED_IN helper hooks. */
|
|
hhook_run_tcp_est_in(tp, th, to);
|
|
|
|
TCPSTAT_ADD(tcps_rcvackbyte, acked);
|
|
sbdrop(&so->so_snd, acked);
|
|
if (SEQ_GT(tp->snd_una, tp->snd_recover) &&
|
|
SEQ_LEQ(th->th_ack, tp->snd_recover))
|
|
tp->snd_recover = th->th_ack - 1;
|
|
|
|
/*
|
|
* Let the congestion control algorithm update
|
|
* congestion control related information. This
|
|
* typically means increasing the congestion
|
|
* window.
|
|
*/
|
|
cc_ack_received(tp, th, CC_ACK);
|
|
|
|
tp->snd_una = th->th_ack;
|
|
tp->t_dupacks = 0;
|
|
m_freem(m);
|
|
|
|
/*
|
|
* If all outstanding data are acked, stop
|
|
* retransmit timer, otherwise restart timer
|
|
* using current (possibly backed-off) value.
|
|
* If process is waiting for space,
|
|
* wakeup/selwakeup/signal. If data
|
|
* are ready to send, let tcp_output
|
|
* decide between more output or persist.
|
|
*/
|
|
#ifdef TCPDEBUG
|
|
if (so->so_options & SO_DEBUG)
|
|
tcp_trace(TA_INPUT, ostate, tp,
|
|
(void *)tcp_saveipgen,
|
|
&tcp_savetcp, 0);
|
|
#endif
|
|
if (tp->snd_una == tp->snd_max)
|
|
tcp_timer_activate(tp, TT_REXMT, 0);
|
|
else if (!tcp_timer_active(tp, TT_PERSIST))
|
|
tcp_timer_activate(tp, TT_REXMT,
|
|
tp->t_rxtcur);
|
|
/* Wake up the socket if we have room to write more */
|
|
sowwakeup(so);
|
|
} else {
|
|
/*
|
|
* Window update only, just free the mbufs and
|
|
* send out whatever we can.
|
|
*/
|
|
m_freem(m);
|
|
}
|
|
if (sbavail(&so->so_snd))
|
|
(void) tcp_output(tp);
|
|
KASSERT(ti_locked == TI_UNLOCKED, ("%s: check_delack ti_locked %d",
|
|
__func__, ti_locked));
|
|
INP_INFO_UNLOCK_ASSERT(&V_tcbinfo);
|
|
INP_WLOCK_ASSERT(tp->t_inpcb);
|
|
|
|
if (tp->t_flags & TF_DELACK) {
|
|
tp->t_flags &= ~TF_DELACK;
|
|
tcp_timer_activate(tp, TT_DELACK, tcp_delacktime);
|
|
}
|
|
INP_WUNLOCK(tp->t_inpcb);
|
|
return (1);
|
|
}
|
|
|
|
/*
|
|
* This tcp-do-segment concentrates on making the fastest
|
|
* ack processing path. It does not have a fast-path for
|
|
* data (it possibly could which would then eliminate the
|
|
* need for fast-slow above). For a content distributor having
|
|
* large outgoing elephants and very very little coming in
|
|
* having no fastpath for data does not really help (since you
|
|
* don't get much data in). The most important thing is
|
|
* processing ack's quickly and getting the rest of the data
|
|
* output to the peer as quickly as possible. This routine
|
|
* seems to be about an overall 3% faster then the old
|
|
* tcp_do_segment and keeps us in the fast-path for packets
|
|
* much more (by allowing window updates to also stay in the fastpath).
|
|
*/
|
|
void
|
|
tcp_do_segment_fastack(struct mbuf *m, struct tcphdr *th, struct socket *so,
|
|
struct tcpcb *tp, int drop_hdrlen, int tlen, uint8_t iptos,
|
|
int ti_locked)
|
|
{
|
|
int thflags;
|
|
u_long tiwin;
|
|
char *s;
|
|
struct in_conninfo *inc;
|
|
struct tcpopt to;
|
|
|
|
thflags = th->th_flags;
|
|
tp->sackhint.last_sack_ack = 0;
|
|
inc = &tp->t_inpcb->inp_inc;
|
|
/*
|
|
* If this is either a state-changing packet or current state isn't
|
|
* established, we require a write lock on tcbinfo. Otherwise, we
|
|
* allow the tcbinfo to be in either alocked or unlocked, as the
|
|
* caller may have unnecessarily acquired a write lock due to a race.
|
|
*/
|
|
if ((thflags & (TH_SYN | TH_FIN | TH_RST)) != 0 ||
|
|
tp->t_state != TCPS_ESTABLISHED) {
|
|
KASSERT(ti_locked == TI_RLOCKED, ("%s ti_locked %d for "
|
|
"SYN/FIN/RST/!EST", __func__, ti_locked));
|
|
INP_INFO_RLOCK_ASSERT(&V_tcbinfo);
|
|
} else {
|
|
#ifdef INVARIANTS
|
|
if (ti_locked == TI_RLOCKED) {
|
|
INP_INFO_RLOCK_ASSERT(&V_tcbinfo);
|
|
} else {
|
|
KASSERT(ti_locked == TI_UNLOCKED, ("%s: EST "
|
|
"ti_locked: %d", __func__, ti_locked));
|
|
INP_INFO_UNLOCK_ASSERT(&V_tcbinfo);
|
|
}
|
|
#endif
|
|
}
|
|
INP_WLOCK_ASSERT(tp->t_inpcb);
|
|
KASSERT(tp->t_state > TCPS_LISTEN, ("%s: TCPS_LISTEN",
|
|
__func__));
|
|
KASSERT(tp->t_state != TCPS_TIME_WAIT, ("%s: TCPS_TIME_WAIT",
|
|
__func__));
|
|
|
|
/*
|
|
* Segment received on connection.
|
|
* Reset idle time and keep-alive timer.
|
|
* XXX: This should be done after segment
|
|
* validation to ignore broken/spoofed segs.
|
|
*/
|
|
tp->t_rcvtime = ticks;
|
|
if (TCPS_HAVEESTABLISHED(tp->t_state))
|
|
tcp_timer_activate(tp, TT_KEEP, TP_KEEPIDLE(tp));
|
|
|
|
/*
|
|
* Unscale the window into a 32-bit value.
|
|
* For the SYN_SENT state the scale is zero.
|
|
*/
|
|
tiwin = th->th_win << tp->snd_scale;
|
|
|
|
/*
|
|
* TCP ECN processing.
|
|
*/
|
|
if (tp->t_flags & TF_ECN_PERMIT) {
|
|
if (thflags & TH_CWR)
|
|
tp->t_flags &= ~TF_ECN_SND_ECE;
|
|
switch (iptos & IPTOS_ECN_MASK) {
|
|
case IPTOS_ECN_CE:
|
|
tp->t_flags |= TF_ECN_SND_ECE;
|
|
TCPSTAT_INC(tcps_ecn_ce);
|
|
break;
|
|
case IPTOS_ECN_ECT0:
|
|
TCPSTAT_INC(tcps_ecn_ect0);
|
|
break;
|
|
case IPTOS_ECN_ECT1:
|
|
TCPSTAT_INC(tcps_ecn_ect1);
|
|
break;
|
|
}
|
|
/* Congestion experienced. */
|
|
if (thflags & TH_ECE) {
|
|
cc_cong_signal(tp, th, CC_ECN);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Parse options on any incoming segment.
|
|
*/
|
|
tcp_dooptions(&to, (u_char *)(th + 1),
|
|
(th->th_off << 2) - sizeof(struct tcphdr),
|
|
(thflags & TH_SYN) ? TO_SYN : 0);
|
|
|
|
/*
|
|
* If echoed timestamp is later than the current time,
|
|
* fall back to non RFC1323 RTT calculation. Normalize
|
|
* timestamp if syncookies were used when this connection
|
|
* was established.
|
|
*/
|
|
if ((to.to_flags & TOF_TS) && (to.to_tsecr != 0)) {
|
|
to.to_tsecr -= tp->ts_offset;
|
|
if (TSTMP_GT(to.to_tsecr, tcp_ts_getticks()))
|
|
to.to_tsecr = 0;
|
|
}
|
|
/*
|
|
* If timestamps were negotiated during SYN/ACK they should
|
|
* appear on every segment during this session and vice versa.
|
|
*/
|
|
if ((tp->t_flags & TF_RCVD_TSTMP) && !(to.to_flags & TOF_TS)) {
|
|
if ((s = tcp_log_addrs(inc, th, NULL, NULL))) {
|
|
log(LOG_DEBUG, "%s; %s: Timestamp missing, "
|
|
"no action\n", s, __func__);
|
|
free(s, M_TCPLOG);
|
|
}
|
|
}
|
|
if (!(tp->t_flags & TF_RCVD_TSTMP) && (to.to_flags & TOF_TS)) {
|
|
if ((s = tcp_log_addrs(inc, th, NULL, NULL))) {
|
|
log(LOG_DEBUG, "%s; %s: Timestamp not expected, "
|
|
"no action\n", s, __func__);
|
|
free(s, M_TCPLOG);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Process options only when we get SYN/ACK back. The SYN case
|
|
* for incoming connections is handled in tcp_syncache.
|
|
* According to RFC1323 the window field in a SYN (i.e., a <SYN>
|
|
* or <SYN,ACK>) segment itself is never scaled.
|
|
* XXX this is traditional behavior, may need to be cleaned up.
|
|
*/
|
|
if (tp->t_state == TCPS_SYN_SENT && (thflags & TH_SYN)) {
|
|
if ((to.to_flags & TOF_SCALE) &&
|
|
(tp->t_flags & TF_REQ_SCALE)) {
|
|
tp->t_flags |= TF_RCVD_SCALE;
|
|
tp->snd_scale = to.to_wscale;
|
|
}
|
|
/*
|
|
* Initial send window. It will be updated with
|
|
* the next incoming segment to the scaled value.
|
|
*/
|
|
tp->snd_wnd = th->th_win;
|
|
if (to.to_flags & TOF_TS) {
|
|
tp->t_flags |= TF_RCVD_TSTMP;
|
|
tp->ts_recent = to.to_tsval;
|
|
tp->ts_recent_age = tcp_ts_getticks();
|
|
}
|
|
if (to.to_flags & TOF_MSS)
|
|
tcp_mss(tp, to.to_mss);
|
|
if ((tp->t_flags & TF_SACK_PERMIT) &&
|
|
(to.to_flags & TOF_SACKPERM) == 0)
|
|
tp->t_flags &= ~TF_SACK_PERMIT;
|
|
}
|
|
/*
|
|
* Header prediction: check for the two common cases
|
|
* of a uni-directional data xfer. If the packet has
|
|
* no control flags, is in-sequence, the window didn't
|
|
* change and we're not retransmitting, it's a
|
|
* candidate. If the length is zero and the ack moved
|
|
* forward, we're the sender side of the xfer. Just
|
|
* free the data acked & wake any higher level process
|
|
* that was blocked waiting for space. If the length
|
|
* is non-zero and the ack didn't move, we're the
|
|
* receiver side. If we're getting packets in-order
|
|
* (the reassembly queue is empty), add the data to
|
|
* the socket buffer and note that we need a delayed ack.
|
|
* Make sure that the hidden state-flags are also off.
|
|
* Since we check for TCPS_ESTABLISHED first, it can only
|
|
* be TH_NEEDSYN.
|
|
*/
|
|
if (__predict_true(tp->t_state == TCPS_ESTABLISHED) &&
|
|
__predict_true(((to.to_flags & TOF_SACK) == 0)) &&
|
|
__predict_true(tlen == 0) &&
|
|
__predict_true((thflags & (TH_SYN|TH_FIN|TH_RST|TH_URG|TH_ACK)) == TH_ACK) &&
|
|
__predict_true(LIST_EMPTY(&tp->t_segq)) &&
|
|
__predict_true(th->th_seq == tp->rcv_nxt)) {
|
|
if (tcp_fastack(m, th, so, tp, &to, drop_hdrlen, tlen,
|
|
ti_locked, tiwin)) {
|
|
return;
|
|
}
|
|
}
|
|
tcp_do_slowpath(m, th, so, tp, &to, drop_hdrlen, tlen,
|
|
ti_locked, tiwin, thflags);
|
|
}
|
|
|
|
struct tcp_function_block __tcp_fastslow = {
|
|
"fastslow",
|
|
tcp_output,
|
|
tcp_do_segment_fastslow,
|
|
tcp_default_ctloutput,
|
|
NULL,
|
|
NULL,
|
|
NULL,
|
|
NULL,
|
|
NULL,
|
|
NULL,
|
|
NULL,
|
|
0,
|
|
0
|
|
|
|
};
|
|
|
|
struct tcp_function_block __tcp_fastack = {
|
|
"fastack",
|
|
tcp_output,
|
|
tcp_do_segment_fastack,
|
|
tcp_default_ctloutput,
|
|
NULL,
|
|
NULL,
|
|
NULL,
|
|
NULL,
|
|
NULL,
|
|
NULL,
|
|
NULL,
|
|
0,
|
|
0
|
|
};
|
|
|
|
static int
|
|
tcp_addfastpaths(module_t mod, int type, void *data)
|
|
{
|
|
int err=0;
|
|
|
|
switch (type) {
|
|
case MOD_LOAD:
|
|
err = register_tcp_functions(&__tcp_fastack, M_WAITOK);
|
|
if (err) {
|
|
printf("Failed to register fastack module -- err:%d\n", err);
|
|
return(err);
|
|
}
|
|
err = register_tcp_functions(&__tcp_fastslow, M_WAITOK);
|
|
if (err) {
|
|
printf("Failed to register fastslow module -- err:%d\n", err);
|
|
deregister_tcp_functions(&__tcp_fastack);
|
|
return(err);
|
|
}
|
|
break;
|
|
case MOD_QUIESCE:
|
|
if ((__tcp_fastslow.tfb_refcnt) ||( __tcp_fastack.tfb_refcnt)) {
|
|
return(EBUSY);
|
|
}
|
|
break;
|
|
case MOD_UNLOAD:
|
|
err = deregister_tcp_functions(&__tcp_fastack);
|
|
if (err == EBUSY)
|
|
break;
|
|
err = deregister_tcp_functions(&__tcp_fastslow);
|
|
if (err == EBUSY)
|
|
break;
|
|
err = 0;
|
|
break;
|
|
default:
|
|
return (EOPNOTSUPP);
|
|
}
|
|
return (err);
|
|
}
|
|
|
|
static moduledata_t new_tcp_fastpaths = {
|
|
.name = "tcp_fastpaths",
|
|
.evhand = tcp_addfastpaths,
|
|
.priv = 0
|
|
};
|
|
|
|
MODULE_VERSION(kern_tcpfastpaths, 1);
|
|
DECLARE_MODULE(kern_tcpfastpaths, new_tcp_fastpaths, SI_SUB_PSEUDO, SI_ORDER_ANY);
|