b0e3ad758b
In order to ensure security and functionality, RFC 1948 style initial sequence number generation has been implemented. Barring any major crypographic breakthroughs, this algorithm should be unbreakable. In addition, the problems with TIME_WAIT recycling which affect our currently used algorithm are not present. Reviewed by: jesper
1481 lines
39 KiB
C
1481 lines
39 KiB
C
/*
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* Copyright (c) 1982, 1986, 1988, 1990, 1993, 1995
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* The Regents of the University of California. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 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_subr.c 8.2 (Berkeley) 5/24/95
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* $FreeBSD$
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*/
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#include "opt_compat.h"
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#include "opt_inet6.h"
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#include "opt_ipsec.h"
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#include "opt_tcpdebug.h"
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/callout.h>
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#include <sys/kernel.h>
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#include <sys/sysctl.h>
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#include <sys/malloc.h>
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#include <sys/mbuf.h>
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#ifdef INET6
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#include <sys/domain.h>
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#endif
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#include <sys/proc.h>
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#include <sys/socket.h>
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#include <sys/socketvar.h>
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#include <sys/protosw.h>
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#include <sys/random.h>
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#include <vm/vm_zone.h>
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#include <net/route.h>
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#include <net/if.h>
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#define _IP_VHL
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#include <netinet/in.h>
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#include <netinet/in_systm.h>
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#include <netinet/ip.h>
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#ifdef INET6
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#include <netinet/ip6.h>
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#endif
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#include <netinet/in_pcb.h>
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#ifdef INET6
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#include <netinet6/in6_pcb.h>
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#endif
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#include <netinet/in_var.h>
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#include <netinet/ip_var.h>
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#ifdef INET6
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#include <netinet6/ip6_var.h>
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#endif
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#include <netinet/tcp.h>
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#include <netinet/tcp_fsm.h>
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#include <netinet/tcp_seq.h>
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#include <netinet/tcp_timer.h>
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#include <netinet/tcp_var.h>
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#ifdef INET6
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#include <netinet6/tcp6_var.h>
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#endif
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#include <netinet/tcpip.h>
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#ifdef TCPDEBUG
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#include <netinet/tcp_debug.h>
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#endif
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#include <netinet6/ip6protosw.h>
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#ifdef IPSEC
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#include <netinet6/ipsec.h>
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#ifdef INET6
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#include <netinet6/ipsec6.h>
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#endif
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#endif /*IPSEC*/
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#include <machine/in_cksum.h>
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#include <sys/md5.h>
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int tcp_mssdflt = TCP_MSS;
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SYSCTL_INT(_net_inet_tcp, TCPCTL_MSSDFLT, mssdflt, CTLFLAG_RW,
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&tcp_mssdflt , 0, "Default TCP Maximum Segment Size");
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#ifdef INET6
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int tcp_v6mssdflt = TCP6_MSS;
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SYSCTL_INT(_net_inet_tcp, TCPCTL_V6MSSDFLT, v6mssdflt,
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CTLFLAG_RW, &tcp_v6mssdflt , 0,
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"Default TCP Maximum Segment Size for IPv6");
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#endif
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#if 0
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static int tcp_rttdflt = TCPTV_SRTTDFLT / PR_SLOWHZ;
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SYSCTL_INT(_net_inet_tcp, TCPCTL_RTTDFLT, rttdflt, CTLFLAG_RW,
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&tcp_rttdflt , 0, "Default maximum TCP Round Trip Time");
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#endif
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static int tcp_do_rfc1323 = 1;
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SYSCTL_INT(_net_inet_tcp, TCPCTL_DO_RFC1323, rfc1323, CTLFLAG_RW,
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&tcp_do_rfc1323 , 0, "Enable rfc1323 (high performance TCP) extensions");
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static int tcp_do_rfc1644 = 0;
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SYSCTL_INT(_net_inet_tcp, TCPCTL_DO_RFC1644, rfc1644, CTLFLAG_RW,
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&tcp_do_rfc1644 , 0, "Enable rfc1644 (TTCP) extensions");
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static int tcp_tcbhashsize = 0;
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SYSCTL_INT(_net_inet_tcp, OID_AUTO, tcbhashsize, CTLFLAG_RD,
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&tcp_tcbhashsize, 0, "Size of TCP control-block hashtable");
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static int do_tcpdrain = 1;
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SYSCTL_INT(_net_inet_tcp, OID_AUTO, do_tcpdrain, CTLFLAG_RW, &do_tcpdrain, 0,
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"Enable tcp_drain routine for extra help when low on mbufs");
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SYSCTL_INT(_net_inet_tcp, OID_AUTO, pcbcount, CTLFLAG_RD,
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&tcbinfo.ipi_count, 0, "Number of active PCBs");
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static int icmp_may_rst = 1;
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SYSCTL_INT(_net_inet_tcp, OID_AUTO, icmp_may_rst, CTLFLAG_RW, &icmp_may_rst, 0,
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"Certain ICMP unreachable messages may abort connections in SYN_SENT");
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static int tcp_strict_rfc1948 = 0;
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SYSCTL_INT(_net_inet_tcp, OID_AUTO, strict_rfc1948, CTLFLAG_RW,
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&tcp_strict_rfc1948, 0, "Determines if RFC1948 is followed exactly");
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static int tcp_isn_reseed_interval = 0;
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SYSCTL_INT(_net_inet_tcp, OID_AUTO, isn_reseed_interval, CTLFLAG_RW,
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&tcp_isn_reseed_interval, 0, "Seconds between reseeding of ISN secret");
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static void tcp_cleartaocache __P((void));
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static void tcp_notify __P((struct inpcb *, int));
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/*
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* Target size of TCP PCB hash tables. Must be a power of two.
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*
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* Note that this can be overridden by the kernel environment
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* variable net.inet.tcp.tcbhashsize
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*/
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#ifndef TCBHASHSIZE
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#define TCBHASHSIZE 512
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#endif
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/*
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* This is the actual shape of what we allocate using the zone
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* allocator. Doing it this way allows us to protect both structures
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* using the same generation count, and also eliminates the overhead
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* of allocating tcpcbs separately. By hiding the structure here,
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* we avoid changing most of the rest of the code (although it needs
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* to be changed, eventually, for greater efficiency).
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*/
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#define ALIGNMENT 32
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#define ALIGNM1 (ALIGNMENT - 1)
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struct inp_tp {
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union {
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struct inpcb inp;
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char align[(sizeof(struct inpcb) + ALIGNM1) & ~ALIGNM1];
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} inp_tp_u;
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struct tcpcb tcb;
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struct callout inp_tp_rexmt, inp_tp_persist, inp_tp_keep, inp_tp_2msl;
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struct callout inp_tp_delack;
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};
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#undef ALIGNMENT
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#undef ALIGNM1
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/*
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* Tcp initialization
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*/
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void
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tcp_init()
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{
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int hashsize = TCBHASHSIZE;
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tcp_ccgen = 1;
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tcp_cleartaocache();
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tcp_delacktime = TCPTV_DELACK;
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tcp_keepinit = TCPTV_KEEP_INIT;
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tcp_keepidle = TCPTV_KEEP_IDLE;
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tcp_keepintvl = TCPTV_KEEPINTVL;
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tcp_maxpersistidle = TCPTV_KEEP_IDLE;
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tcp_msl = TCPTV_MSL;
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LIST_INIT(&tcb);
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tcbinfo.listhead = &tcb;
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TUNABLE_INT_FETCH("net.inet.tcp.tcbhashsize", &hashsize);
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if (!powerof2(hashsize)) {
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printf("WARNING: TCB hash size not a power of 2\n");
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hashsize = 512; /* safe default */
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}
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tcp_tcbhashsize = hashsize;
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tcbinfo.hashbase = hashinit(hashsize, M_PCB, &tcbinfo.hashmask);
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tcbinfo.porthashbase = hashinit(hashsize, M_PCB,
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&tcbinfo.porthashmask);
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tcbinfo.ipi_zone = zinit("tcpcb", sizeof(struct inp_tp), maxsockets,
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ZONE_INTERRUPT, 0);
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#ifdef INET6
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#define TCP_MINPROTOHDR (sizeof(struct ip6_hdr) + sizeof(struct tcphdr))
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#else /* INET6 */
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#define TCP_MINPROTOHDR (sizeof(struct tcpiphdr))
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#endif /* INET6 */
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if (max_protohdr < TCP_MINPROTOHDR)
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max_protohdr = TCP_MINPROTOHDR;
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if (max_linkhdr + TCP_MINPROTOHDR > MHLEN)
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panic("tcp_init");
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#undef TCP_MINPROTOHDR
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}
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/*
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* Fill in the IP and TCP headers for an outgoing packet, given the tcpcb.
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* tcp_template used to store this data in mbufs, but we now recopy it out
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* of the tcpcb each time to conserve mbufs.
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*/
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void
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tcp_fillheaders(tp, ip_ptr, tcp_ptr)
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struct tcpcb *tp;
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void *ip_ptr;
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void *tcp_ptr;
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{
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struct inpcb *inp = tp->t_inpcb;
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struct tcphdr *tcp_hdr = (struct tcphdr *)tcp_ptr;
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#ifdef INET6
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if ((inp->inp_vflag & INP_IPV6) != 0) {
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struct ip6_hdr *ip6;
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ip6 = (struct ip6_hdr *)ip_ptr;
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ip6->ip6_flow = (ip6->ip6_flow & ~IPV6_FLOWINFO_MASK) |
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(inp->in6p_flowinfo & IPV6_FLOWINFO_MASK);
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ip6->ip6_vfc = (ip6->ip6_vfc & ~IPV6_VERSION_MASK) |
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(IPV6_VERSION & IPV6_VERSION_MASK);
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ip6->ip6_nxt = IPPROTO_TCP;
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ip6->ip6_plen = sizeof(struct tcphdr);
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ip6->ip6_src = inp->in6p_laddr;
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ip6->ip6_dst = inp->in6p_faddr;
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tcp_hdr->th_sum = 0;
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} else
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#endif
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{
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struct ip *ip = (struct ip *) ip_ptr;
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ip->ip_vhl = IP_VHL_BORING;
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ip->ip_tos = 0;
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ip->ip_len = 0;
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ip->ip_id = 0;
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ip->ip_off = 0;
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ip->ip_ttl = 0;
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ip->ip_sum = 0;
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ip->ip_p = IPPROTO_TCP;
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ip->ip_src = inp->inp_laddr;
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ip->ip_dst = inp->inp_faddr;
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tcp_hdr->th_sum = in_pseudo(ip->ip_src.s_addr, ip->ip_dst.s_addr,
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htons(sizeof(struct tcphdr) + IPPROTO_TCP));
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}
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tcp_hdr->th_sport = inp->inp_lport;
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tcp_hdr->th_dport = inp->inp_fport;
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tcp_hdr->th_seq = 0;
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tcp_hdr->th_ack = 0;
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tcp_hdr->th_x2 = 0;
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tcp_hdr->th_off = 5;
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tcp_hdr->th_flags = 0;
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tcp_hdr->th_win = 0;
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tcp_hdr->th_urp = 0;
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}
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/*
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* Create template to be used to send tcp packets on a connection.
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* Allocates an mbuf and fills in a skeletal tcp/ip header. The only
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* use for this function is in keepalives, which use tcp_respond.
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*/
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struct tcptemp *
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tcp_maketemplate(tp)
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struct tcpcb *tp;
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{
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struct mbuf *m;
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struct tcptemp *n;
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m = m_get(M_DONTWAIT, MT_HEADER);
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if (m == NULL)
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return (0);
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m->m_len = sizeof(struct tcptemp);
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n = mtod(m, struct tcptemp *);
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tcp_fillheaders(tp, (void *)&n->tt_ipgen, (void *)&n->tt_t);
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return (n);
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}
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/*
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* Send a single message to the TCP at address specified by
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* the given TCP/IP header. If m == 0, then we make a copy
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* of the tcpiphdr at ti and send directly to the addressed host.
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* This is used to force keep alive messages out using the TCP
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* template for a connection. If flags are given then we send
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* a message back to the TCP which originated the * segment ti,
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* and discard the mbuf containing it and any other attached mbufs.
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*
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* In any case the ack and sequence number of the transmitted
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* segment are as specified by the parameters.
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*
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* NOTE: If m != NULL, then ti must point to *inside* the mbuf.
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*/
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void
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tcp_respond(tp, ipgen, th, m, ack, seq, flags)
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struct tcpcb *tp;
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void *ipgen;
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register struct tcphdr *th;
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register struct mbuf *m;
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tcp_seq ack, seq;
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int flags;
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{
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register int tlen;
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int win = 0;
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struct route *ro = 0;
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struct route sro;
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struct ip *ip;
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struct tcphdr *nth;
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#ifdef INET6
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struct route_in6 *ro6 = 0;
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struct route_in6 sro6;
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struct ip6_hdr *ip6;
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int isipv6;
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#endif /* INET6 */
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int ipflags = 0;
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#ifdef INET6
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isipv6 = IP_VHL_V(((struct ip *)ipgen)->ip_vhl) == 6;
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ip6 = ipgen;
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#endif /* INET6 */
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ip = ipgen;
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if (tp) {
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if (!(flags & TH_RST)) {
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win = sbspace(&tp->t_inpcb->inp_socket->so_rcv);
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if (win > (long)TCP_MAXWIN << tp->rcv_scale)
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win = (long)TCP_MAXWIN << tp->rcv_scale;
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}
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#ifdef INET6
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if (isipv6)
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ro6 = &tp->t_inpcb->in6p_route;
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else
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#endif /* INET6 */
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ro = &tp->t_inpcb->inp_route;
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} else {
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#ifdef INET6
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if (isipv6) {
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ro6 = &sro6;
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bzero(ro6, sizeof *ro6);
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} else
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#endif /* INET6 */
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{
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ro = &sro;
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bzero(ro, sizeof *ro);
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}
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}
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if (m == 0) {
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m = m_gethdr(M_DONTWAIT, MT_HEADER);
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if (m == NULL)
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return;
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tlen = 0;
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m->m_data += max_linkhdr;
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#ifdef INET6
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if (isipv6) {
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bcopy((caddr_t)ip6, mtod(m, caddr_t),
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sizeof(struct ip6_hdr));
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ip6 = mtod(m, struct ip6_hdr *);
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nth = (struct tcphdr *)(ip6 + 1);
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} else
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#endif /* INET6 */
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{
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bcopy((caddr_t)ip, mtod(m, caddr_t), sizeof(struct ip));
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ip = mtod(m, struct ip *);
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nth = (struct tcphdr *)(ip + 1);
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}
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bcopy((caddr_t)th, (caddr_t)nth, sizeof(struct tcphdr));
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flags = TH_ACK;
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} else {
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m_freem(m->m_next);
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m->m_next = 0;
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m->m_data = (caddr_t)ipgen;
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/* m_len is set later */
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tlen = 0;
|
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#define xchg(a,b,type) { type t; t=a; a=b; b=t; }
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#ifdef INET6
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if (isipv6) {
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xchg(ip6->ip6_dst, ip6->ip6_src, struct in6_addr);
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nth = (struct tcphdr *)(ip6 + 1);
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} else
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#endif /* INET6 */
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{
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xchg(ip->ip_dst.s_addr, ip->ip_src.s_addr, n_long);
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nth = (struct tcphdr *)(ip + 1);
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}
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if (th != nth) {
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/*
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* this is usually a case when an extension header
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* exists between the IPv6 header and the
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* TCP header.
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*/
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nth->th_sport = th->th_sport;
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nth->th_dport = th->th_dport;
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}
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xchg(nth->th_dport, nth->th_sport, n_short);
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#undef xchg
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}
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#ifdef INET6
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if (isipv6) {
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ip6->ip6_plen = htons((u_short)(sizeof (struct tcphdr) +
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tlen));
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tlen += sizeof (struct ip6_hdr) + sizeof (struct tcphdr);
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} else
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#endif
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{
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tlen += sizeof (struct tcpiphdr);
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ip->ip_len = tlen;
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ip->ip_ttl = ip_defttl;
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}
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m->m_len = tlen;
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m->m_pkthdr.len = tlen;
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m->m_pkthdr.rcvif = (struct ifnet *) 0;
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nth->th_seq = htonl(seq);
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nth->th_ack = htonl(ack);
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nth->th_x2 = 0;
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nth->th_off = sizeof (struct tcphdr) >> 2;
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nth->th_flags = flags;
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if (tp)
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nth->th_win = htons((u_short) (win >> tp->rcv_scale));
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else
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nth->th_win = htons((u_short)win);
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nth->th_urp = 0;
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#ifdef INET6
|
|
if (isipv6) {
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nth->th_sum = 0;
|
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nth->th_sum = in6_cksum(m, IPPROTO_TCP,
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sizeof(struct ip6_hdr),
|
|
tlen - sizeof(struct ip6_hdr));
|
|
ip6->ip6_hlim = in6_selecthlim(tp ? tp->t_inpcb : NULL,
|
|
ro6 && ro6->ro_rt ?
|
|
ro6->ro_rt->rt_ifp :
|
|
NULL);
|
|
} else
|
|
#endif /* INET6 */
|
|
{
|
|
nth->th_sum = in_pseudo(ip->ip_src.s_addr, ip->ip_dst.s_addr,
|
|
htons((u_short)(tlen - sizeof(struct ip) + ip->ip_p)));
|
|
m->m_pkthdr.csum_flags = CSUM_TCP;
|
|
m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum);
|
|
}
|
|
#ifdef TCPDEBUG
|
|
if (tp == NULL || (tp->t_inpcb->inp_socket->so_options & SO_DEBUG))
|
|
tcp_trace(TA_OUTPUT, 0, tp, mtod(m, void *), th, 0);
|
|
#endif
|
|
#ifdef IPSEC
|
|
if (ipsec_setsocket(m, tp ? tp->t_inpcb->inp_socket : NULL) != 0) {
|
|
m_freem(m);
|
|
return;
|
|
}
|
|
#endif
|
|
#ifdef INET6
|
|
if (isipv6) {
|
|
(void)ip6_output(m, NULL, ro6, ipflags, NULL, NULL);
|
|
if (ro6 == &sro6 && ro6->ro_rt) {
|
|
RTFREE(ro6->ro_rt);
|
|
ro6->ro_rt = NULL;
|
|
}
|
|
} else
|
|
#endif /* INET6 */
|
|
{
|
|
(void) ip_output(m, NULL, ro, ipflags, NULL);
|
|
if (ro == &sro && ro->ro_rt) {
|
|
RTFREE(ro->ro_rt);
|
|
ro->ro_rt = NULL;
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Create a new TCP control block, making an
|
|
* empty reassembly queue and hooking it to the argument
|
|
* protocol control block. The `inp' parameter must have
|
|
* come from the zone allocator set up in tcp_init().
|
|
*/
|
|
struct tcpcb *
|
|
tcp_newtcpcb(inp)
|
|
struct inpcb *inp;
|
|
{
|
|
struct inp_tp *it;
|
|
register struct tcpcb *tp;
|
|
#ifdef INET6
|
|
int isipv6 = (inp->inp_vflag & INP_IPV6) != 0;
|
|
#endif /* INET6 */
|
|
|
|
it = (struct inp_tp *)inp;
|
|
tp = &it->tcb;
|
|
bzero((char *) tp, sizeof(struct tcpcb));
|
|
LIST_INIT(&tp->t_segq);
|
|
tp->t_maxseg = tp->t_maxopd =
|
|
#ifdef INET6
|
|
isipv6 ? tcp_v6mssdflt :
|
|
#endif /* INET6 */
|
|
tcp_mssdflt;
|
|
|
|
/* Set up our timeouts. */
|
|
callout_init(tp->tt_rexmt = &it->inp_tp_rexmt, 0);
|
|
callout_init(tp->tt_persist = &it->inp_tp_persist, 0);
|
|
callout_init(tp->tt_keep = &it->inp_tp_keep, 0);
|
|
callout_init(tp->tt_2msl = &it->inp_tp_2msl, 0);
|
|
callout_init(tp->tt_delack = &it->inp_tp_delack, 0);
|
|
|
|
if (tcp_do_rfc1323)
|
|
tp->t_flags = (TF_REQ_SCALE|TF_REQ_TSTMP);
|
|
if (tcp_do_rfc1644)
|
|
tp->t_flags |= TF_REQ_CC;
|
|
tp->t_inpcb = inp; /* XXX */
|
|
/*
|
|
* Init srtt to TCPTV_SRTTBASE (0), so we can tell that we have no
|
|
* rtt estimate. Set rttvar so that srtt + 4 * rttvar gives
|
|
* reasonable initial retransmit time.
|
|
*/
|
|
tp->t_srtt = TCPTV_SRTTBASE;
|
|
tp->t_rttvar = ((TCPTV_RTOBASE - TCPTV_SRTTBASE) << TCP_RTTVAR_SHIFT) / 4;
|
|
tp->t_rttmin = TCPTV_MIN;
|
|
tp->t_rxtcur = TCPTV_RTOBASE;
|
|
tp->snd_cwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT;
|
|
tp->snd_ssthresh = TCP_MAXWIN << TCP_MAX_WINSHIFT;
|
|
tp->t_rcvtime = ticks;
|
|
/*
|
|
* IPv4 TTL initialization is necessary for an IPv6 socket as well,
|
|
* because the socket may be bound to an IPv6 wildcard address,
|
|
* which may match an IPv4-mapped IPv6 address.
|
|
*/
|
|
inp->inp_ip_ttl = ip_defttl;
|
|
inp->inp_ppcb = (caddr_t)tp;
|
|
return (tp); /* XXX */
|
|
}
|
|
|
|
/*
|
|
* Drop a TCP connection, reporting
|
|
* the specified error. If connection is synchronized,
|
|
* then send a RST to peer.
|
|
*/
|
|
struct tcpcb *
|
|
tcp_drop(tp, errno)
|
|
register struct tcpcb *tp;
|
|
int errno;
|
|
{
|
|
struct socket *so = tp->t_inpcb->inp_socket;
|
|
|
|
if (TCPS_HAVERCVDSYN(tp->t_state)) {
|
|
tp->t_state = TCPS_CLOSED;
|
|
(void) tcp_output(tp);
|
|
tcpstat.tcps_drops++;
|
|
} else
|
|
tcpstat.tcps_conndrops++;
|
|
if (errno == ETIMEDOUT && tp->t_softerror)
|
|
errno = tp->t_softerror;
|
|
so->so_error = errno;
|
|
return (tcp_close(tp));
|
|
}
|
|
|
|
/*
|
|
* Close a TCP control block:
|
|
* discard all space held by the tcp
|
|
* discard internet protocol block
|
|
* wake up any sleepers
|
|
*/
|
|
struct tcpcb *
|
|
tcp_close(tp)
|
|
register struct tcpcb *tp;
|
|
{
|
|
register struct tseg_qent *q;
|
|
struct inpcb *inp = tp->t_inpcb;
|
|
struct socket *so = inp->inp_socket;
|
|
#ifdef INET6
|
|
int isipv6 = (inp->inp_vflag & INP_IPV6) != 0;
|
|
#endif /* INET6 */
|
|
register struct rtentry *rt;
|
|
int dosavessthresh;
|
|
|
|
/*
|
|
* Make sure that all of our timers are stopped before we
|
|
* delete the PCB.
|
|
*/
|
|
callout_stop(tp->tt_rexmt);
|
|
callout_stop(tp->tt_persist);
|
|
callout_stop(tp->tt_keep);
|
|
callout_stop(tp->tt_2msl);
|
|
callout_stop(tp->tt_delack);
|
|
|
|
/*
|
|
* If we got enough samples through the srtt filter,
|
|
* save the rtt and rttvar in the routing entry.
|
|
* 'Enough' is arbitrarily defined as the 16 samples.
|
|
* 16 samples is enough for the srtt filter to converge
|
|
* to within 5% of the correct value; fewer samples and
|
|
* we could save a very bogus rtt.
|
|
*
|
|
* Don't update the default route's characteristics and don't
|
|
* update anything that the user "locked".
|
|
*/
|
|
if (tp->t_rttupdated >= 16) {
|
|
register u_long i = 0;
|
|
#ifdef INET6
|
|
if (isipv6) {
|
|
struct sockaddr_in6 *sin6;
|
|
|
|
if ((rt = inp->in6p_route.ro_rt) == NULL)
|
|
goto no_valid_rt;
|
|
sin6 = (struct sockaddr_in6 *)rt_key(rt);
|
|
if (IN6_IS_ADDR_UNSPECIFIED(&sin6->sin6_addr))
|
|
goto no_valid_rt;
|
|
}
|
|
else
|
|
#endif /* INET6 */
|
|
if ((rt = inp->inp_route.ro_rt) == NULL ||
|
|
((struct sockaddr_in *)rt_key(rt))->sin_addr.s_addr
|
|
== INADDR_ANY)
|
|
goto no_valid_rt;
|
|
|
|
if ((rt->rt_rmx.rmx_locks & RTV_RTT) == 0) {
|
|
i = tp->t_srtt *
|
|
(RTM_RTTUNIT / (hz * TCP_RTT_SCALE));
|
|
if (rt->rt_rmx.rmx_rtt && i)
|
|
/*
|
|
* filter this update to half the old & half
|
|
* the new values, converting scale.
|
|
* See route.h and tcp_var.h for a
|
|
* description of the scaling constants.
|
|
*/
|
|
rt->rt_rmx.rmx_rtt =
|
|
(rt->rt_rmx.rmx_rtt + i) / 2;
|
|
else
|
|
rt->rt_rmx.rmx_rtt = i;
|
|
tcpstat.tcps_cachedrtt++;
|
|
}
|
|
if ((rt->rt_rmx.rmx_locks & RTV_RTTVAR) == 0) {
|
|
i = tp->t_rttvar *
|
|
(RTM_RTTUNIT / (hz * TCP_RTTVAR_SCALE));
|
|
if (rt->rt_rmx.rmx_rttvar && i)
|
|
rt->rt_rmx.rmx_rttvar =
|
|
(rt->rt_rmx.rmx_rttvar + i) / 2;
|
|
else
|
|
rt->rt_rmx.rmx_rttvar = i;
|
|
tcpstat.tcps_cachedrttvar++;
|
|
}
|
|
/*
|
|
* The old comment here said:
|
|
* update the pipelimit (ssthresh) if it has been updated
|
|
* already or if a pipesize was specified & the threshhold
|
|
* got below half the pipesize. I.e., wait for bad news
|
|
* before we start updating, then update on both good
|
|
* and bad news.
|
|
*
|
|
* But we want to save the ssthresh even if no pipesize is
|
|
* specified explicitly in the route, because such
|
|
* connections still have an implicit pipesize specified
|
|
* by the global tcp_sendspace. In the absence of a reliable
|
|
* way to calculate the pipesize, it will have to do.
|
|
*/
|
|
i = tp->snd_ssthresh;
|
|
if (rt->rt_rmx.rmx_sendpipe != 0)
|
|
dosavessthresh = (i < rt->rt_rmx.rmx_sendpipe / 2);
|
|
else
|
|
dosavessthresh = (i < so->so_snd.sb_hiwat / 2);
|
|
if (((rt->rt_rmx.rmx_locks & RTV_SSTHRESH) == 0 &&
|
|
i != 0 && rt->rt_rmx.rmx_ssthresh != 0)
|
|
|| dosavessthresh) {
|
|
/*
|
|
* convert the limit from user data bytes to
|
|
* packets then to packet data bytes.
|
|
*/
|
|
i = (i + tp->t_maxseg / 2) / tp->t_maxseg;
|
|
if (i < 2)
|
|
i = 2;
|
|
i *= (u_long)(tp->t_maxseg +
|
|
#ifdef INET6
|
|
(isipv6 ? sizeof (struct ip6_hdr) +
|
|
sizeof (struct tcphdr) :
|
|
#endif
|
|
sizeof (struct tcpiphdr)
|
|
#ifdef INET6
|
|
)
|
|
#endif
|
|
);
|
|
if (rt->rt_rmx.rmx_ssthresh)
|
|
rt->rt_rmx.rmx_ssthresh =
|
|
(rt->rt_rmx.rmx_ssthresh + i) / 2;
|
|
else
|
|
rt->rt_rmx.rmx_ssthresh = i;
|
|
tcpstat.tcps_cachedssthresh++;
|
|
}
|
|
}
|
|
rt = inp->inp_route.ro_rt;
|
|
if (rt) {
|
|
/*
|
|
* mark route for deletion if no information is
|
|
* cached.
|
|
*/
|
|
if ((tp->t_flags & TF_LQ_OVERFLOW) &&
|
|
((rt->rt_rmx.rmx_locks & RTV_RTT) == 0)){
|
|
if (rt->rt_rmx.rmx_rtt == 0)
|
|
rt->rt_flags |= RTF_DELCLONE;
|
|
}
|
|
}
|
|
no_valid_rt:
|
|
/* free the reassembly queue, if any */
|
|
while((q = LIST_FIRST(&tp->t_segq)) != NULL) {
|
|
LIST_REMOVE(q, tqe_q);
|
|
m_freem(q->tqe_m);
|
|
FREE(q, M_TSEGQ);
|
|
}
|
|
inp->inp_ppcb = NULL;
|
|
soisdisconnected(so);
|
|
#ifdef INET6
|
|
if (INP_CHECK_SOCKAF(so, AF_INET6))
|
|
in6_pcbdetach(inp);
|
|
else
|
|
#endif /* INET6 */
|
|
in_pcbdetach(inp);
|
|
tcpstat.tcps_closed++;
|
|
return ((struct tcpcb *)0);
|
|
}
|
|
|
|
void
|
|
tcp_drain()
|
|
{
|
|
if (do_tcpdrain)
|
|
{
|
|
struct inpcb *inpb;
|
|
struct tcpcb *tcpb;
|
|
struct tseg_qent *te;
|
|
|
|
/*
|
|
* Walk the tcpbs, if existing, and flush the reassembly queue,
|
|
* if there is one...
|
|
* XXX: The "Net/3" implementation doesn't imply that the TCP
|
|
* reassembly queue should be flushed, but in a situation
|
|
* where we're really low on mbufs, this is potentially
|
|
* usefull.
|
|
*/
|
|
LIST_FOREACH(inpb, tcbinfo.listhead, inp_list) {
|
|
if ((tcpb = intotcpcb(inpb))) {
|
|
while ((te = LIST_FIRST(&tcpb->t_segq))
|
|
!= NULL) {
|
|
LIST_REMOVE(te, tqe_q);
|
|
m_freem(te->tqe_m);
|
|
FREE(te, M_TSEGQ);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Notify a tcp user of an asynchronous error;
|
|
* store error as soft error, but wake up user
|
|
* (for now, won't do anything until can select for soft error).
|
|
*
|
|
* Do not wake up user since there currently is no mechanism for
|
|
* reporting soft errors (yet - a kqueue filter may be added).
|
|
*/
|
|
static void
|
|
tcp_notify(inp, error)
|
|
struct inpcb *inp;
|
|
int error;
|
|
{
|
|
struct tcpcb *tp = (struct tcpcb *)inp->inp_ppcb;
|
|
|
|
/*
|
|
* Ignore some errors if we are hooked up.
|
|
* If connection hasn't completed, has retransmitted several times,
|
|
* and receives a second error, give up now. This is better
|
|
* than waiting a long time to establish a connection that
|
|
* can never complete.
|
|
*/
|
|
if (tp->t_state == TCPS_ESTABLISHED &&
|
|
(error == EHOSTUNREACH || error == ENETUNREACH ||
|
|
error == EHOSTDOWN)) {
|
|
return;
|
|
} else if (tp->t_state < TCPS_ESTABLISHED && tp->t_rxtshift > 3 &&
|
|
tp->t_softerror)
|
|
tcp_drop(tp, error);
|
|
else
|
|
tp->t_softerror = error;
|
|
#if 0
|
|
wakeup((caddr_t) &so->so_timeo);
|
|
sorwakeup(so);
|
|
sowwakeup(so);
|
|
#endif
|
|
}
|
|
|
|
static int
|
|
tcp_pcblist(SYSCTL_HANDLER_ARGS)
|
|
{
|
|
int error, i, n, s;
|
|
struct inpcb *inp, **inp_list;
|
|
inp_gen_t gencnt;
|
|
struct xinpgen xig;
|
|
|
|
/*
|
|
* The process of preparing the TCB list is too time-consuming and
|
|
* resource-intensive to repeat twice on every request.
|
|
*/
|
|
if (req->oldptr == 0) {
|
|
n = tcbinfo.ipi_count;
|
|
req->oldidx = 2 * (sizeof xig)
|
|
+ (n + n/8) * sizeof(struct xtcpcb);
|
|
return 0;
|
|
}
|
|
|
|
if (req->newptr != 0)
|
|
return EPERM;
|
|
|
|
/*
|
|
* OK, now we're committed to doing something.
|
|
*/
|
|
s = splnet();
|
|
gencnt = tcbinfo.ipi_gencnt;
|
|
n = tcbinfo.ipi_count;
|
|
splx(s);
|
|
|
|
xig.xig_len = sizeof xig;
|
|
xig.xig_count = n;
|
|
xig.xig_gen = gencnt;
|
|
xig.xig_sogen = so_gencnt;
|
|
error = SYSCTL_OUT(req, &xig, sizeof xig);
|
|
if (error)
|
|
return error;
|
|
|
|
inp_list = malloc(n * sizeof *inp_list, M_TEMP, M_WAITOK);
|
|
if (inp_list == 0)
|
|
return ENOMEM;
|
|
|
|
s = splnet();
|
|
for (inp = LIST_FIRST(tcbinfo.listhead), i = 0; inp && i < n;
|
|
inp = LIST_NEXT(inp, inp_list)) {
|
|
if (inp->inp_gencnt <= gencnt && !prison_xinpcb(req->p, inp))
|
|
inp_list[i++] = inp;
|
|
}
|
|
splx(s);
|
|
n = i;
|
|
|
|
error = 0;
|
|
for (i = 0; i < n; i++) {
|
|
inp = inp_list[i];
|
|
if (inp->inp_gencnt <= gencnt) {
|
|
struct xtcpcb xt;
|
|
caddr_t inp_ppcb;
|
|
xt.xt_len = sizeof xt;
|
|
/* XXX should avoid extra copy */
|
|
bcopy(inp, &xt.xt_inp, sizeof *inp);
|
|
inp_ppcb = inp->inp_ppcb;
|
|
if (inp_ppcb != NULL)
|
|
bcopy(inp_ppcb, &xt.xt_tp, sizeof xt.xt_tp);
|
|
else
|
|
bzero((char *) &xt.xt_tp, sizeof xt.xt_tp);
|
|
if (inp->inp_socket)
|
|
sotoxsocket(inp->inp_socket, &xt.xt_socket);
|
|
error = SYSCTL_OUT(req, &xt, sizeof xt);
|
|
}
|
|
}
|
|
if (!error) {
|
|
/*
|
|
* Give the user an updated idea of our state.
|
|
* If the generation differs from what we told
|
|
* her before, she knows that something happened
|
|
* while we were processing this request, and it
|
|
* might be necessary to retry.
|
|
*/
|
|
s = splnet();
|
|
xig.xig_gen = tcbinfo.ipi_gencnt;
|
|
xig.xig_sogen = so_gencnt;
|
|
xig.xig_count = tcbinfo.ipi_count;
|
|
splx(s);
|
|
error = SYSCTL_OUT(req, &xig, sizeof xig);
|
|
}
|
|
free(inp_list, M_TEMP);
|
|
return error;
|
|
}
|
|
|
|
SYSCTL_PROC(_net_inet_tcp, TCPCTL_PCBLIST, pcblist, CTLFLAG_RD, 0, 0,
|
|
tcp_pcblist, "S,xtcpcb", "List of active TCP connections");
|
|
|
|
static int
|
|
tcp_getcred(SYSCTL_HANDLER_ARGS)
|
|
{
|
|
struct xucred xuc;
|
|
struct sockaddr_in addrs[2];
|
|
struct inpcb *inp;
|
|
int error, s;
|
|
|
|
error = suser_xxx(0, req->p, PRISON_ROOT);
|
|
if (error)
|
|
return (error);
|
|
error = SYSCTL_IN(req, addrs, sizeof(addrs));
|
|
if (error)
|
|
return (error);
|
|
s = splnet();
|
|
inp = in_pcblookup_hash(&tcbinfo, addrs[1].sin_addr, addrs[1].sin_port,
|
|
addrs[0].sin_addr, addrs[0].sin_port, 0, NULL);
|
|
if (inp == NULL || inp->inp_socket == NULL) {
|
|
error = ENOENT;
|
|
goto out;
|
|
}
|
|
error = u_cansee(req->p->p_ucred, inp->inp_socket->so_cred);
|
|
if (error)
|
|
goto out;
|
|
bzero(&xuc, sizeof(xuc));
|
|
xuc.cr_uid = inp->inp_socket->so_cred->cr_uid;
|
|
xuc.cr_ngroups = inp->inp_socket->so_cred->cr_ngroups;
|
|
bcopy(inp->inp_socket->so_cred->cr_groups, xuc.cr_groups,
|
|
sizeof(xuc.cr_groups));
|
|
error = SYSCTL_OUT(req, &xuc, sizeof(struct xucred));
|
|
out:
|
|
splx(s);
|
|
return (error);
|
|
}
|
|
|
|
SYSCTL_PROC(_net_inet_tcp, OID_AUTO, getcred,
|
|
CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_PRISON, 0, 0,
|
|
tcp_getcred, "S,xucred", "Get the xucred of a TCP connection");
|
|
|
|
#ifdef INET6
|
|
static int
|
|
tcp6_getcred(SYSCTL_HANDLER_ARGS)
|
|
{
|
|
struct xucred xuc;
|
|
struct sockaddr_in6 addrs[2];
|
|
struct inpcb *inp;
|
|
int error, s, mapped = 0;
|
|
|
|
error = suser_xxx(0, req->p, PRISON_ROOT);
|
|
if (error)
|
|
return (error);
|
|
error = SYSCTL_IN(req, addrs, sizeof(addrs));
|
|
if (error)
|
|
return (error);
|
|
if (IN6_IS_ADDR_V4MAPPED(&addrs[0].sin6_addr)) {
|
|
if (IN6_IS_ADDR_V4MAPPED(&addrs[1].sin6_addr))
|
|
mapped = 1;
|
|
else
|
|
return (EINVAL);
|
|
}
|
|
s = splnet();
|
|
if (mapped == 1)
|
|
inp = in_pcblookup_hash(&tcbinfo,
|
|
*(struct in_addr *)&addrs[1].sin6_addr.s6_addr[12],
|
|
addrs[1].sin6_port,
|
|
*(struct in_addr *)&addrs[0].sin6_addr.s6_addr[12],
|
|
addrs[0].sin6_port,
|
|
0, NULL);
|
|
else
|
|
inp = in6_pcblookup_hash(&tcbinfo, &addrs[1].sin6_addr,
|
|
addrs[1].sin6_port,
|
|
&addrs[0].sin6_addr, addrs[0].sin6_port,
|
|
0, NULL);
|
|
if (inp == NULL || inp->inp_socket == NULL) {
|
|
error = ENOENT;
|
|
goto out;
|
|
}
|
|
error = u_cansee(req->p->p_ucred, inp->inp_socket->so_cred);
|
|
if (error)
|
|
goto out;
|
|
bzero(&xuc, sizeof(xuc));
|
|
xuc.cr_uid = inp->inp_socket->so_cred->cr_uid;
|
|
xuc.cr_ngroups = inp->inp_socket->so_cred->cr_ngroups;
|
|
bcopy(inp->inp_socket->so_cred->cr_groups, xuc.cr_groups,
|
|
sizeof(xuc.cr_groups));
|
|
error = SYSCTL_OUT(req, &xuc, sizeof(struct xucred));
|
|
out:
|
|
splx(s);
|
|
return (error);
|
|
}
|
|
|
|
SYSCTL_PROC(_net_inet6_tcp6, OID_AUTO, getcred,
|
|
CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_PRISON, 0, 0,
|
|
tcp6_getcred, "S,xucred", "Get the xucred of a TCP6 connection");
|
|
#endif
|
|
|
|
|
|
void
|
|
tcp_ctlinput(cmd, sa, vip)
|
|
int cmd;
|
|
struct sockaddr *sa;
|
|
void *vip;
|
|
{
|
|
struct ip *ip = vip;
|
|
struct tcphdr *th;
|
|
struct in_addr faddr;
|
|
struct inpcb *inp;
|
|
struct tcpcb *tp;
|
|
void (*notify) __P((struct inpcb *, int)) = tcp_notify;
|
|
tcp_seq icmp_seq;
|
|
int s;
|
|
|
|
faddr = ((struct sockaddr_in *)sa)->sin_addr;
|
|
if (sa->sa_family != AF_INET || faddr.s_addr == INADDR_ANY)
|
|
return;
|
|
|
|
if (cmd == PRC_QUENCH)
|
|
notify = tcp_quench;
|
|
else if (icmp_may_rst && (cmd == PRC_UNREACH_ADMIN_PROHIB ||
|
|
cmd == PRC_UNREACH_PORT) && ip)
|
|
notify = tcp_drop_syn_sent;
|
|
else if (cmd == PRC_MSGSIZE)
|
|
notify = tcp_mtudisc;
|
|
else if (PRC_IS_REDIRECT(cmd)) {
|
|
ip = 0;
|
|
notify = in_rtchange;
|
|
} else if (cmd == PRC_HOSTDEAD)
|
|
ip = 0;
|
|
else if ((unsigned)cmd > PRC_NCMDS || inetctlerrmap[cmd] == 0)
|
|
return;
|
|
if (ip) {
|
|
s = splnet();
|
|
th = (struct tcphdr *)((caddr_t)ip
|
|
+ (IP_VHL_HL(ip->ip_vhl) << 2));
|
|
inp = in_pcblookup_hash(&tcbinfo, faddr, th->th_dport,
|
|
ip->ip_src, th->th_sport, 0, NULL);
|
|
if (inp != NULL && inp->inp_socket != NULL) {
|
|
icmp_seq = htonl(th->th_seq);
|
|
tp = intotcpcb(inp);
|
|
if (SEQ_GEQ(icmp_seq, tp->snd_una) &&
|
|
SEQ_LT(icmp_seq, tp->snd_max))
|
|
(*notify)(inp, inetctlerrmap[cmd]);
|
|
}
|
|
splx(s);
|
|
} else
|
|
in_pcbnotifyall(&tcb, faddr, inetctlerrmap[cmd], notify);
|
|
}
|
|
|
|
#ifdef INET6
|
|
void
|
|
tcp6_ctlinput(cmd, sa, d)
|
|
int cmd;
|
|
struct sockaddr *sa;
|
|
void *d;
|
|
{
|
|
struct tcphdr th;
|
|
void (*notify) __P((struct inpcb *, int)) = tcp_notify;
|
|
struct ip6_hdr *ip6;
|
|
struct mbuf *m;
|
|
struct ip6ctlparam *ip6cp = NULL;
|
|
const struct sockaddr_in6 *sa6_src = NULL;
|
|
int off;
|
|
struct tcp_portonly {
|
|
u_int16_t th_sport;
|
|
u_int16_t th_dport;
|
|
} *thp;
|
|
|
|
if (sa->sa_family != AF_INET6 ||
|
|
sa->sa_len != sizeof(struct sockaddr_in6))
|
|
return;
|
|
|
|
if (cmd == PRC_QUENCH)
|
|
notify = tcp_quench;
|
|
else if (cmd == PRC_MSGSIZE)
|
|
notify = tcp_mtudisc;
|
|
else if (!PRC_IS_REDIRECT(cmd) &&
|
|
((unsigned)cmd > PRC_NCMDS || inet6ctlerrmap[cmd] == 0))
|
|
return;
|
|
|
|
/* if the parameter is from icmp6, decode it. */
|
|
if (d != NULL) {
|
|
ip6cp = (struct ip6ctlparam *)d;
|
|
m = ip6cp->ip6c_m;
|
|
ip6 = ip6cp->ip6c_ip6;
|
|
off = ip6cp->ip6c_off;
|
|
sa6_src = ip6cp->ip6c_src;
|
|
} else {
|
|
m = NULL;
|
|
ip6 = NULL;
|
|
off = 0; /* fool gcc */
|
|
sa6_src = &sa6_any;
|
|
}
|
|
|
|
if (ip6) {
|
|
/*
|
|
* XXX: We assume that when IPV6 is non NULL,
|
|
* M and OFF are valid.
|
|
*/
|
|
|
|
/* check if we can safely examine src and dst ports */
|
|
if (m->m_pkthdr.len < off + sizeof(*thp))
|
|
return;
|
|
|
|
bzero(&th, sizeof(th));
|
|
m_copydata(m, off, sizeof(*thp), (caddr_t)&th);
|
|
|
|
in6_pcbnotify(&tcb, sa, th.th_dport,
|
|
(struct sockaddr *)ip6cp->ip6c_src,
|
|
th.th_sport, cmd, notify);
|
|
} else
|
|
in6_pcbnotify(&tcb, sa, 0, (struct sockaddr *)sa6_src,
|
|
0, cmd, notify);
|
|
}
|
|
#endif /* INET6 */
|
|
|
|
|
|
/*
|
|
* Following is where TCP initial sequence number generation occurs.
|
|
*
|
|
* There are two places where we must use initial sequence numbers:
|
|
* 1. In SYN-ACK packets.
|
|
* 2. In SYN packets.
|
|
*
|
|
* The ISNs in SYN-ACK packets have no monotonicity requirement,
|
|
* and should be as unpredictable as possible to avoid the possibility
|
|
* of spoofing and/or connection hijacking. To satisfy this
|
|
* requirement, SYN-ACK ISNs are generated via the arc4random()
|
|
* function. If exact RFC 1948 compliance is requested via sysctl,
|
|
* these ISNs will be generated just like those in SYN packets.
|
|
*
|
|
* The ISNs in SYN packets must be monotonic; TIME_WAIT recycling
|
|
* depends on this property. In addition, these ISNs should be
|
|
* unguessable so as to prevent connection hijacking. To satisfy
|
|
* the requirements of this situation, the algorithm outlined in
|
|
* RFC 1948 is used to generate sequence numbers.
|
|
*
|
|
* For more information on the theory of operation, please see
|
|
* RFC 1948.
|
|
*
|
|
* Implementation details:
|
|
*
|
|
* Time is based off the system timer, and is corrected so that it
|
|
* increases by one megabyte per second. This allows for proper
|
|
* recycling on high speed LANs while still leaving over an hour
|
|
* before rollover.
|
|
*
|
|
* Two sysctls control the generation of ISNs:
|
|
*
|
|
* net.inet.tcp.isn_reseed_interval controls the number of seconds
|
|
* between seeding of isn_secret. This is normally set to zero,
|
|
* as reseeding should not be necessary.
|
|
*
|
|
* net.inet.tcp.strict_rfc1948 controls whether RFC 1948 is followed
|
|
* strictly. When strict compliance is requested, reseeding is
|
|
* disabled and SYN-ACKs will be generated in the same manner as
|
|
* SYNs. Strict mode is disabled by default.
|
|
*
|
|
*/
|
|
|
|
#define ISN_BYTES_PER_SECOND 1048576
|
|
|
|
u_char isn_secret[32];
|
|
int isn_last_reseed;
|
|
MD5_CTX isn_ctx;
|
|
|
|
tcp_seq
|
|
tcp_new_isn(tp)
|
|
struct tcpcb *tp;
|
|
{
|
|
u_int32_t md5_buffer[4];
|
|
tcp_seq new_isn;
|
|
|
|
/* Use arc4random for SYN-ACKs when not in exact RFC1948 mode. */
|
|
if (((tp->t_state == TCPS_LISTEN) || (tp->t_state == TCPS_TIME_WAIT))
|
|
&& tcp_strict_rfc1948 == 0)
|
|
return arc4random();
|
|
|
|
/* Seed if this is the first use, reseed if requested. */
|
|
if ((isn_last_reseed == 0) ||
|
|
((tcp_strict_rfc1948 == 0) && (tcp_isn_reseed_interval > 0) &&
|
|
(((u_int)isn_last_reseed + (u_int)tcp_isn_reseed_interval*hz)
|
|
< (u_int)ticks))) {
|
|
read_random(&isn_secret, sizeof(isn_secret));
|
|
isn_last_reseed = ticks;
|
|
}
|
|
|
|
/* Compute the md5 hash and return the ISN. */
|
|
MD5Init(&isn_ctx);
|
|
MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_fport, sizeof(u_short));
|
|
MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_lport, sizeof(u_short));
|
|
#ifdef INET6
|
|
if ((tp->t_inpcb->inp_vflag & INP_IPV6) != 0) {
|
|
MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->in6p_faddr,
|
|
sizeof(struct in6_addr));
|
|
MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->in6p_laddr,
|
|
sizeof(struct in6_addr));
|
|
} else
|
|
#endif
|
|
{
|
|
MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_faddr,
|
|
sizeof(struct in_addr));
|
|
MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_laddr,
|
|
sizeof(struct in_addr));
|
|
}
|
|
MD5Update(&isn_ctx, (u_char *) &isn_secret, sizeof(isn_secret));
|
|
MD5Final((u_char *) &md5_buffer, &isn_ctx);
|
|
new_isn = (tcp_seq) md5_buffer[0];
|
|
new_isn += ticks * (ISN_BYTES_PER_SECOND / hz);
|
|
return new_isn;
|
|
}
|
|
|
|
/*
|
|
* When a source quench is received, close congestion window
|
|
* to one segment. We will gradually open it again as we proceed.
|
|
*/
|
|
void
|
|
tcp_quench(inp, errno)
|
|
struct inpcb *inp;
|
|
int errno;
|
|
{
|
|
struct tcpcb *tp = intotcpcb(inp);
|
|
|
|
if (tp)
|
|
tp->snd_cwnd = tp->t_maxseg;
|
|
}
|
|
|
|
/*
|
|
* When a specific ICMP unreachable message is received and the
|
|
* connection state is SYN-SENT, drop the connection. This behavior
|
|
* is controlled by the icmp_may_rst sysctl.
|
|
*/
|
|
void
|
|
tcp_drop_syn_sent(inp, errno)
|
|
struct inpcb *inp;
|
|
int errno;
|
|
{
|
|
struct tcpcb *tp = intotcpcb(inp);
|
|
|
|
if (tp && tp->t_state == TCPS_SYN_SENT)
|
|
tcp_drop(tp, errno);
|
|
}
|
|
|
|
/*
|
|
* When `need fragmentation' ICMP is received, update our idea of the MSS
|
|
* based on the new value in the route. Also nudge TCP to send something,
|
|
* since we know the packet we just sent was dropped.
|
|
* This duplicates some code in the tcp_mss() function in tcp_input.c.
|
|
*/
|
|
void
|
|
tcp_mtudisc(inp, errno)
|
|
struct inpcb *inp;
|
|
int errno;
|
|
{
|
|
struct tcpcb *tp = intotcpcb(inp);
|
|
struct rtentry *rt;
|
|
struct rmxp_tao *taop;
|
|
struct socket *so = inp->inp_socket;
|
|
int offered;
|
|
int mss;
|
|
#ifdef INET6
|
|
int isipv6 = (tp->t_inpcb->inp_vflag & INP_IPV6) != 0;
|
|
#endif /* INET6 */
|
|
|
|
if (tp) {
|
|
#ifdef INET6
|
|
if (isipv6)
|
|
rt = tcp_rtlookup6(inp);
|
|
else
|
|
#endif /* INET6 */
|
|
rt = tcp_rtlookup(inp);
|
|
if (!rt || !rt->rt_rmx.rmx_mtu) {
|
|
tp->t_maxopd = tp->t_maxseg =
|
|
#ifdef INET6
|
|
isipv6 ? tcp_v6mssdflt :
|
|
#endif /* INET6 */
|
|
tcp_mssdflt;
|
|
return;
|
|
}
|
|
taop = rmx_taop(rt->rt_rmx);
|
|
offered = taop->tao_mssopt;
|
|
mss = rt->rt_rmx.rmx_mtu -
|
|
#ifdef INET6
|
|
(isipv6 ?
|
|
sizeof(struct ip6_hdr) + sizeof(struct tcphdr) :
|
|
#endif /* INET6 */
|
|
sizeof(struct tcpiphdr)
|
|
#ifdef INET6
|
|
)
|
|
#endif /* INET6 */
|
|
;
|
|
|
|
if (offered)
|
|
mss = min(mss, offered);
|
|
/*
|
|
* XXX - The above conditional probably violates the TCP
|
|
* spec. The problem is that, since we don't know the
|
|
* other end's MSS, we are supposed to use a conservative
|
|
* default. But, if we do that, then MTU discovery will
|
|
* never actually take place, because the conservative
|
|
* default is much less than the MTUs typically seen
|
|
* on the Internet today. For the moment, we'll sweep
|
|
* this under the carpet.
|
|
*
|
|
* The conservative default might not actually be a problem
|
|
* if the only case this occurs is when sending an initial
|
|
* SYN with options and data to a host we've never talked
|
|
* to before. Then, they will reply with an MSS value which
|
|
* will get recorded and the new parameters should get
|
|
* recomputed. For Further Study.
|
|
*/
|
|
if (tp->t_maxopd <= mss)
|
|
return;
|
|
tp->t_maxopd = mss;
|
|
|
|
if ((tp->t_flags & (TF_REQ_TSTMP|TF_NOOPT)) == TF_REQ_TSTMP &&
|
|
(tp->t_flags & TF_RCVD_TSTMP) == TF_RCVD_TSTMP)
|
|
mss -= TCPOLEN_TSTAMP_APPA;
|
|
if ((tp->t_flags & (TF_REQ_CC|TF_NOOPT)) == TF_REQ_CC &&
|
|
(tp->t_flags & TF_RCVD_CC) == TF_RCVD_CC)
|
|
mss -= TCPOLEN_CC_APPA;
|
|
#if (MCLBYTES & (MCLBYTES - 1)) == 0
|
|
if (mss > MCLBYTES)
|
|
mss &= ~(MCLBYTES-1);
|
|
#else
|
|
if (mss > MCLBYTES)
|
|
mss = mss / MCLBYTES * MCLBYTES;
|
|
#endif
|
|
if (so->so_snd.sb_hiwat < mss)
|
|
mss = so->so_snd.sb_hiwat;
|
|
|
|
tp->t_maxseg = mss;
|
|
|
|
tcpstat.tcps_mturesent++;
|
|
tp->t_rtttime = 0;
|
|
tp->snd_nxt = tp->snd_una;
|
|
tcp_output(tp);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Look-up the routing entry to the peer of this inpcb. If no route
|
|
* is found and it cannot be allocated the return NULL. This routine
|
|
* is called by TCP routines that access the rmx structure and by tcp_mss
|
|
* to get the interface MTU.
|
|
*/
|
|
struct rtentry *
|
|
tcp_rtlookup(inp)
|
|
struct inpcb *inp;
|
|
{
|
|
struct route *ro;
|
|
struct rtentry *rt;
|
|
|
|
ro = &inp->inp_route;
|
|
rt = ro->ro_rt;
|
|
if (rt == NULL || !(rt->rt_flags & RTF_UP)) {
|
|
/* No route yet, so try to acquire one */
|
|
if (inp->inp_faddr.s_addr != INADDR_ANY) {
|
|
ro->ro_dst.sa_family = AF_INET;
|
|
ro->ro_dst.sa_len = sizeof(struct sockaddr_in);
|
|
((struct sockaddr_in *) &ro->ro_dst)->sin_addr =
|
|
inp->inp_faddr;
|
|
rtalloc(ro);
|
|
rt = ro->ro_rt;
|
|
}
|
|
}
|
|
return rt;
|
|
}
|
|
|
|
#ifdef INET6
|
|
struct rtentry *
|
|
tcp_rtlookup6(inp)
|
|
struct inpcb *inp;
|
|
{
|
|
struct route_in6 *ro6;
|
|
struct rtentry *rt;
|
|
|
|
ro6 = &inp->in6p_route;
|
|
rt = ro6->ro_rt;
|
|
if (rt == NULL || !(rt->rt_flags & RTF_UP)) {
|
|
/* No route yet, so try to acquire one */
|
|
if (!IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_faddr)) {
|
|
struct sockaddr_in6 *dst6;
|
|
|
|
dst6 = (struct sockaddr_in6 *)&ro6->ro_dst;
|
|
dst6->sin6_family = AF_INET6;
|
|
dst6->sin6_len = sizeof(*dst6);
|
|
dst6->sin6_addr = inp->in6p_faddr;
|
|
rtalloc((struct route *)ro6);
|
|
rt = ro6->ro_rt;
|
|
}
|
|
}
|
|
return rt;
|
|
}
|
|
#endif /* INET6 */
|
|
|
|
#ifdef IPSEC
|
|
/* compute ESP/AH header size for TCP, including outer IP header. */
|
|
size_t
|
|
ipsec_hdrsiz_tcp(tp)
|
|
struct tcpcb *tp;
|
|
{
|
|
struct inpcb *inp;
|
|
struct mbuf *m;
|
|
size_t hdrsiz;
|
|
struct ip *ip;
|
|
#ifdef INET6
|
|
struct ip6_hdr *ip6;
|
|
#endif /* INET6 */
|
|
struct tcphdr *th;
|
|
|
|
if ((tp == NULL) || ((inp = tp->t_inpcb) == NULL))
|
|
return 0;
|
|
MGETHDR(m, M_DONTWAIT, MT_DATA);
|
|
if (!m)
|
|
return 0;
|
|
|
|
#ifdef INET6
|
|
if ((inp->inp_vflag & INP_IPV6) != 0) {
|
|
ip6 = mtod(m, struct ip6_hdr *);
|
|
th = (struct tcphdr *)(ip6 + 1);
|
|
m->m_pkthdr.len = m->m_len =
|
|
sizeof(struct ip6_hdr) + sizeof(struct tcphdr);
|
|
tcp_fillheaders(tp, ip6, th);
|
|
hdrsiz = ipsec6_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp);
|
|
} else
|
|
#endif /* INET6 */
|
|
{
|
|
ip = mtod(m, struct ip *);
|
|
th = (struct tcphdr *)(ip + 1);
|
|
m->m_pkthdr.len = m->m_len = sizeof(struct tcpiphdr);
|
|
tcp_fillheaders(tp, ip, th);
|
|
hdrsiz = ipsec4_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp);
|
|
}
|
|
|
|
m_free(m);
|
|
return hdrsiz;
|
|
}
|
|
#endif /*IPSEC*/
|
|
|
|
/*
|
|
* Return a pointer to the cached information about the remote host.
|
|
* The cached information is stored in the protocol specific part of
|
|
* the route metrics.
|
|
*/
|
|
struct rmxp_tao *
|
|
tcp_gettaocache(inp)
|
|
struct inpcb *inp;
|
|
{
|
|
struct rtentry *rt;
|
|
|
|
#ifdef INET6
|
|
if ((inp->inp_vflag & INP_IPV6) != 0)
|
|
rt = tcp_rtlookup6(inp);
|
|
else
|
|
#endif /* INET6 */
|
|
rt = tcp_rtlookup(inp);
|
|
|
|
/* Make sure this is a host route and is up. */
|
|
if (rt == NULL ||
|
|
(rt->rt_flags & (RTF_UP|RTF_HOST)) != (RTF_UP|RTF_HOST))
|
|
return NULL;
|
|
|
|
return rmx_taop(rt->rt_rmx);
|
|
}
|
|
|
|
/*
|
|
* Clear all the TAO cache entries, called from tcp_init.
|
|
*
|
|
* XXX
|
|
* This routine is just an empty one, because we assume that the routing
|
|
* routing tables are initialized at the same time when TCP, so there is
|
|
* nothing in the cache left over.
|
|
*/
|
|
static void
|
|
tcp_cleartaocache()
|
|
{
|
|
}
|