2 * Copyright (c) 2003, 2004 Jeffrey M. Hsu. All rights reserved.
3 * Copyright (c) 2003, 2004 The DragonFly Project. All rights reserved.
5 * This code is derived from software contributed to The DragonFly Project
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. Neither the name of The DragonFly Project nor the names of its
17 * contributors may be used to endorse or promote products derived
18 * from this software without specific, prior written permission.
20 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
22 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
23 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
24 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
25 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
26 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
27 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
28 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
29 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
30 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
35 * Copyright (c) 1982, 1986, 1988, 1990, 1993, 1995
36 * The Regents of the University of California. All rights reserved.
38 * Redistribution and use in source and binary forms, with or without
39 * modification, are permitted provided that the following conditions
41 * 1. Redistributions of source code must retain the above copyright
42 * notice, this list of conditions and the following disclaimer.
43 * 2. Redistributions in binary form must reproduce the above copyright
44 * notice, this list of conditions and the following disclaimer in the
45 * documentation and/or other materials provided with the distribution.
46 * 3. All advertising materials mentioning features or use of this software
47 * must display the following acknowledgement:
48 * This product includes software developed by the University of
49 * California, Berkeley and its contributors.
50 * 4. Neither the name of the University nor the names of its contributors
51 * may be used to endorse or promote products derived from this software
52 * without specific prior written permission.
54 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
55 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
56 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
57 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
58 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
59 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
60 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
61 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
62 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
63 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
66 * @(#)tcp_subr.c 8.2 (Berkeley) 5/24/95
67 * $FreeBSD: src/sys/netinet/tcp_subr.c,v 1.73.2.31 2003/01/24 05:11:34 sam Exp $
68 * $DragonFly: src/sys/netinet/tcp_subr.c,v 1.63 2008/11/11 10:46:58 sephe Exp $
71 #include "opt_compat.h"
72 #include "opt_inet6.h"
73 #include "opt_ipsec.h"
74 #include "opt_tcpdebug.h"
76 #include <sys/param.h>
77 #include <sys/systm.h>
78 #include <sys/callout.h>
79 #include <sys/kernel.h>
80 #include <sys/sysctl.h>
81 #include <sys/malloc.h>
82 #include <sys/mpipe.h>
85 #include <sys/domain.h>
89 #include <sys/socket.h>
90 #include <sys/socketvar.h>
91 #include <sys/protosw.h>
92 #include <sys/random.h>
93 #include <sys/in_cksum.h>
96 #include <vm/vm_zone.h>
98 #include <net/route.h>
100 #include <net/netisr.h>
103 #include <netinet/in.h>
104 #include <netinet/in_systm.h>
105 #include <netinet/ip.h>
106 #include <netinet/ip6.h>
107 #include <netinet/in_pcb.h>
108 #include <netinet6/in6_pcb.h>
109 #include <netinet/in_var.h>
110 #include <netinet/ip_var.h>
111 #include <netinet6/ip6_var.h>
112 #include <netinet/ip_icmp.h>
114 #include <netinet/icmp6.h>
116 #include <netinet/tcp.h>
117 #include <netinet/tcp_fsm.h>
118 #include <netinet/tcp_seq.h>
119 #include <netinet/tcp_timer.h>
120 #include <netinet/tcp_timer2.h>
121 #include <netinet/tcp_var.h>
122 #include <netinet6/tcp6_var.h>
123 #include <netinet/tcpip.h>
125 #include <netinet/tcp_debug.h>
127 #include <netinet6/ip6protosw.h>
130 #include <netinet6/ipsec.h>
132 #include <netinet6/ipsec6.h>
137 #include <netproto/ipsec/ipsec.h>
139 #include <netproto/ipsec/ipsec6.h>
145 #include <sys/msgport2.h>
146 #include <machine/smp.h>
148 #include <net/netmsg2.h>
150 #if !defined(KTR_TCP)
151 #define KTR_TCP KTR_ALL
153 KTR_INFO_MASTER(tcp
);
154 KTR_INFO(KTR_TCP
, tcp
, rxmsg
, 0, "tcp getmsg", 0);
155 KTR_INFO(KTR_TCP
, tcp
, wait
, 1, "tcp waitmsg", 0);
156 KTR_INFO(KTR_TCP
, tcp
, delayed
, 2, "tcp execute delayed ops", 0);
157 #define logtcp(name) KTR_LOG(tcp_ ## name)
159 struct inpcbinfo tcbinfo
[MAXCPU
];
160 struct tcpcbackqhead tcpcbackq
[MAXCPU
];
162 int tcp_mpsafe_proto
= 0;
163 TUNABLE_INT("net.inet.tcp.mpsafe_proto", &tcp_mpsafe_proto
);
165 static int tcp_mpsafe_thread
= NETMSG_SERVICE_ADAPTIVE
;
166 TUNABLE_INT("net.inet.tcp.mpsafe_thread", &tcp_mpsafe_thread
);
167 SYSCTL_INT(_net_inet_tcp
, OID_AUTO
, mpsafe_thread
, CTLFLAG_RW
,
168 &tcp_mpsafe_thread
, 0,
169 "0:BGL, 1:Adaptive BGL, 2:No BGL(experimental)");
171 int tcp_mssdflt
= TCP_MSS
;
172 SYSCTL_INT(_net_inet_tcp
, TCPCTL_MSSDFLT
, mssdflt
, CTLFLAG_RW
,
173 &tcp_mssdflt
, 0, "Default TCP Maximum Segment Size");
176 int tcp_v6mssdflt
= TCP6_MSS
;
177 SYSCTL_INT(_net_inet_tcp
, TCPCTL_V6MSSDFLT
, v6mssdflt
, CTLFLAG_RW
,
178 &tcp_v6mssdflt
, 0, "Default TCP Maximum Segment Size for IPv6");
182 * Minimum MSS we accept and use. This prevents DoS attacks where
183 * we are forced to a ridiculous low MSS like 20 and send hundreds
184 * of packets instead of one. The effect scales with the available
185 * bandwidth and quickly saturates the CPU and network interface
186 * with packet generation and sending. Set to zero to disable MINMSS
187 * checking. This setting prevents us from sending too small packets.
189 int tcp_minmss
= TCP_MINMSS
;
190 SYSCTL_INT(_net_inet_tcp
, OID_AUTO
, minmss
, CTLFLAG_RW
,
191 &tcp_minmss
, 0, "Minmum TCP Maximum Segment Size");
194 static int tcp_rttdflt
= TCPTV_SRTTDFLT
/ PR_SLOWHZ
;
195 SYSCTL_INT(_net_inet_tcp
, TCPCTL_RTTDFLT
, rttdflt
, CTLFLAG_RW
,
196 &tcp_rttdflt
, 0, "Default maximum TCP Round Trip Time");
199 int tcp_do_rfc1323
= 1;
200 SYSCTL_INT(_net_inet_tcp
, TCPCTL_DO_RFC1323
, rfc1323
, CTLFLAG_RW
,
201 &tcp_do_rfc1323
, 0, "Enable rfc1323 (high performance TCP) extensions");
203 int tcp_do_rfc1644
= 0;
204 SYSCTL_INT(_net_inet_tcp
, TCPCTL_DO_RFC1644
, rfc1644
, CTLFLAG_RW
,
205 &tcp_do_rfc1644
, 0, "Enable rfc1644 (TTCP) extensions");
207 static int tcp_tcbhashsize
= 0;
208 SYSCTL_INT(_net_inet_tcp
, OID_AUTO
, tcbhashsize
, CTLFLAG_RD
,
209 &tcp_tcbhashsize
, 0, "Size of TCP control block hashtable");
211 static int do_tcpdrain
= 1;
212 SYSCTL_INT(_net_inet_tcp
, OID_AUTO
, do_tcpdrain
, CTLFLAG_RW
, &do_tcpdrain
, 0,
213 "Enable tcp_drain routine for extra help when low on mbufs");
216 SYSCTL_INT(_net_inet_tcp
, OID_AUTO
, pcbcount
, CTLFLAG_RD
,
217 &tcbinfo
[0].ipi_count
, 0, "Number of active PCBs");
219 static int icmp_may_rst
= 1;
220 SYSCTL_INT(_net_inet_tcp
, OID_AUTO
, icmp_may_rst
, CTLFLAG_RW
, &icmp_may_rst
, 0,
221 "Certain ICMP unreachable messages may abort connections in SYN_SENT");
223 static int tcp_isn_reseed_interval
= 0;
224 SYSCTL_INT(_net_inet_tcp
, OID_AUTO
, isn_reseed_interval
, CTLFLAG_RW
,
225 &tcp_isn_reseed_interval
, 0, "Seconds between reseeding of ISN secret");
228 * TCP bandwidth limiting sysctls. The inflight limiter is now turned on
229 * by default, but with generous values which should allow maximal
230 * bandwidth. In particular, the slop defaults to 50 (5 packets).
232 * The reason for doing this is that the limiter is the only mechanism we
233 * have which seems to do a really good job preventing receiver RX rings
234 * on network interfaces from getting blown out. Even though GigE/10GigE
235 * is supposed to flow control it looks like either it doesn't actually
236 * do it or Open Source drivers do not properly enable it.
238 * People using the limiter to reduce bottlenecks on slower WAN connections
239 * should set the slop to 20 (2 packets).
241 static int tcp_inflight_enable
= 1;
242 SYSCTL_INT(_net_inet_tcp
, OID_AUTO
, inflight_enable
, CTLFLAG_RW
,
243 &tcp_inflight_enable
, 0, "Enable automatic TCP inflight data limiting");
245 static int tcp_inflight_debug
= 0;
246 SYSCTL_INT(_net_inet_tcp
, OID_AUTO
, inflight_debug
, CTLFLAG_RW
,
247 &tcp_inflight_debug
, 0, "Debug TCP inflight calculations");
249 static int tcp_inflight_min
= 6144;
250 SYSCTL_INT(_net_inet_tcp
, OID_AUTO
, inflight_min
, CTLFLAG_RW
,
251 &tcp_inflight_min
, 0, "Lower bound for TCP inflight window");
253 static int tcp_inflight_max
= TCP_MAXWIN
<< TCP_MAX_WINSHIFT
;
254 SYSCTL_INT(_net_inet_tcp
, OID_AUTO
, inflight_max
, CTLFLAG_RW
,
255 &tcp_inflight_max
, 0, "Upper bound for TCP inflight window");
257 static int tcp_inflight_stab
= 50;
258 SYSCTL_INT(_net_inet_tcp
, OID_AUTO
, inflight_stab
, CTLFLAG_RW
,
259 &tcp_inflight_stab
, 0, "Slop in maximal packets / 10 (20 = 3 packets)");
261 static MALLOC_DEFINE(M_TCPTEMP
, "tcptemp", "TCP Templates for Keepalives");
262 static struct malloc_pipe tcptemp_mpipe
;
264 static void tcp_willblock(int);
265 static void tcp_cleartaocache (void);
266 static void tcp_notify (struct inpcb
*, int);
268 struct tcp_stats tcpstats_percpu
[MAXCPU
];
271 sysctl_tcpstats(SYSCTL_HANDLER_ARGS
)
275 for (cpu
= 0; cpu
< ncpus
; ++cpu
) {
276 if ((error
= SYSCTL_OUT(req
, &tcpstats_percpu
[cpu
],
277 sizeof(struct tcp_stats
))))
279 if ((error
= SYSCTL_IN(req
, &tcpstats_percpu
[cpu
],
280 sizeof(struct tcp_stats
))))
286 SYSCTL_PROC(_net_inet_tcp
, TCPCTL_STATS
, stats
, (CTLTYPE_OPAQUE
| CTLFLAG_RW
),
287 0, 0, sysctl_tcpstats
, "S,tcp_stats", "TCP statistics");
289 SYSCTL_STRUCT(_net_inet_tcp
, TCPCTL_STATS
, stats
, CTLFLAG_RW
,
290 &tcpstat
, tcp_stats
, "TCP statistics");
294 * Target size of TCP PCB hash tables. Must be a power of two.
296 * Note that this can be overridden by the kernel environment
297 * variable net.inet.tcp.tcbhashsize
300 #define TCBHASHSIZE 512
304 * This is the actual shape of what we allocate using the zone
305 * allocator. Doing it this way allows us to protect both structures
306 * using the same generation count, and also eliminates the overhead
307 * of allocating tcpcbs separately. By hiding the structure here,
308 * we avoid changing most of the rest of the code (although it needs
309 * to be changed, eventually, for greater efficiency).
312 #define ALIGNM1 (ALIGNMENT - 1)
316 char align
[(sizeof(struct inpcb
) + ALIGNM1
) & ~ALIGNM1
];
319 struct tcp_callout inp_tp_rexmt
;
320 struct tcp_callout inp_tp_persist
;
321 struct tcp_callout inp_tp_keep
;
322 struct tcp_callout inp_tp_2msl
;
323 struct tcp_callout inp_tp_delack
;
324 struct netmsg_tcp_timer inp_tp_timermsg
;
335 struct inpcbporthead
*porthashbase
;
337 struct vm_zone
*ipi_zone
;
338 int hashsize
= TCBHASHSIZE
;
342 * note: tcptemp is used for keepalives, and it is ok for an
343 * allocation to fail so do not specify MPF_INT.
345 mpipe_init(&tcptemp_mpipe
, M_TCPTEMP
, sizeof(struct tcptemp
),
351 tcp_delacktime
= TCPTV_DELACK
;
352 tcp_keepinit
= TCPTV_KEEP_INIT
;
353 tcp_keepidle
= TCPTV_KEEP_IDLE
;
354 tcp_keepintvl
= TCPTV_KEEPINTVL
;
355 tcp_maxpersistidle
= TCPTV_KEEP_IDLE
;
357 tcp_rexmit_min
= TCPTV_MIN
;
358 tcp_rexmit_slop
= TCPTV_CPU_VAR
;
360 TUNABLE_INT_FETCH("net.inet.tcp.tcbhashsize", &hashsize
);
361 if (!powerof2(hashsize
)) {
362 kprintf("WARNING: TCB hash size not a power of 2\n");
363 hashsize
= 512; /* safe default */
365 tcp_tcbhashsize
= hashsize
;
366 porthashbase
= hashinit(hashsize
, M_PCB
, &porthashmask
);
367 ipi_zone
= zinit("tcpcb", sizeof(struct inp_tp
), maxsockets
,
370 for (cpu
= 0; cpu
< ncpus2
; cpu
++) {
371 in_pcbinfo_init(&tcbinfo
[cpu
]);
372 tcbinfo
[cpu
].cpu
= cpu
;
373 tcbinfo
[cpu
].hashbase
= hashinit(hashsize
, M_PCB
,
374 &tcbinfo
[cpu
].hashmask
);
375 tcbinfo
[cpu
].porthashbase
= porthashbase
;
376 tcbinfo
[cpu
].porthashmask
= porthashmask
;
377 tcbinfo
[cpu
].wildcardhashbase
= hashinit(hashsize
, M_PCB
,
378 &tcbinfo
[cpu
].wildcardhashmask
);
379 tcbinfo
[cpu
].ipi_zone
= ipi_zone
;
380 TAILQ_INIT(&tcpcbackq
[cpu
]);
383 tcp_reass_maxseg
= nmbclusters
/ 16;
384 TUNABLE_INT_FETCH("net.inet.tcp.reass.maxsegments", &tcp_reass_maxseg
);
387 #define TCP_MINPROTOHDR (sizeof(struct ip6_hdr) + sizeof(struct tcphdr))
389 #define TCP_MINPROTOHDR (sizeof(struct tcpiphdr))
391 if (max_protohdr
< TCP_MINPROTOHDR
)
392 max_protohdr
= TCP_MINPROTOHDR
;
393 if (max_linkhdr
+ TCP_MINPROTOHDR
> MHLEN
)
395 #undef TCP_MINPROTOHDR
398 * Initialize TCP statistics counters for each CPU.
401 for (cpu
= 0; cpu
< ncpus
; ++cpu
) {
402 bzero(&tcpstats_percpu
[cpu
], sizeof(struct tcp_stats
));
405 bzero(&tcpstat
, sizeof(struct tcp_stats
));
413 tcpmsg_service_loop(void *dummy
)
419 * Thread was started with TDF_MPSAFE
423 while ((msg
= lwkt_waitport(&curthread
->td_msgport
, 0))) {
426 mplocked
= netmsg_service(msg
, tcp_mpsafe_thread
,
428 } while ((msg
= lwkt_getport(&curthread
->td_msgport
)) != NULL
);
431 tcp_willblock(mplocked
);
437 tcp_willblock(int mplocked
)
440 int cpu
= mycpu
->gd_cpuid
;
443 if (!mplocked
&& !tcp_mpsafe_proto
) {
444 if (TAILQ_EMPTY(&tcpcbackq
[cpu
]))
452 while ((tp
= TAILQ_FIRST(&tcpcbackq
[cpu
])) != NULL
) {
453 KKASSERT(tp
->t_flags
& TF_ONOUTPUTQ
);
454 tp
->t_flags
&= ~TF_ONOUTPUTQ
;
455 TAILQ_REMOVE(&tcpcbackq
[cpu
], tp
, t_outputq
);
465 * Fill in the IP and TCP headers for an outgoing packet, given the tcpcb.
466 * tcp_template used to store this data in mbufs, but we now recopy it out
467 * of the tcpcb each time to conserve mbufs.
470 tcp_fillheaders(struct tcpcb
*tp
, void *ip_ptr
, void *tcp_ptr
)
472 struct inpcb
*inp
= tp
->t_inpcb
;
473 struct tcphdr
*tcp_hdr
= (struct tcphdr
*)tcp_ptr
;
476 if (inp
->inp_vflag
& INP_IPV6
) {
479 ip6
= (struct ip6_hdr
*)ip_ptr
;
480 ip6
->ip6_flow
= (ip6
->ip6_flow
& ~IPV6_FLOWINFO_MASK
) |
481 (inp
->in6p_flowinfo
& IPV6_FLOWINFO_MASK
);
482 ip6
->ip6_vfc
= (ip6
->ip6_vfc
& ~IPV6_VERSION_MASK
) |
483 (IPV6_VERSION
& IPV6_VERSION_MASK
);
484 ip6
->ip6_nxt
= IPPROTO_TCP
;
485 ip6
->ip6_plen
= sizeof(struct tcphdr
);
486 ip6
->ip6_src
= inp
->in6p_laddr
;
487 ip6
->ip6_dst
= inp
->in6p_faddr
;
492 struct ip
*ip
= (struct ip
*) ip_ptr
;
494 ip
->ip_vhl
= IP_VHL_BORING
;
501 ip
->ip_p
= IPPROTO_TCP
;
502 ip
->ip_src
= inp
->inp_laddr
;
503 ip
->ip_dst
= inp
->inp_faddr
;
504 tcp_hdr
->th_sum
= in_pseudo(ip
->ip_src
.s_addr
,
506 htons(sizeof(struct tcphdr
) + IPPROTO_TCP
));
509 tcp_hdr
->th_sport
= inp
->inp_lport
;
510 tcp_hdr
->th_dport
= inp
->inp_fport
;
515 tcp_hdr
->th_flags
= 0;
521 * Create template to be used to send tcp packets on a connection.
522 * Allocates an mbuf and fills in a skeletal tcp/ip header. The only
523 * use for this function is in keepalives, which use tcp_respond.
526 tcp_maketemplate(struct tcpcb
*tp
)
530 if ((tmp
= mpipe_alloc_nowait(&tcptemp_mpipe
)) == NULL
)
532 tcp_fillheaders(tp
, &tmp
->tt_ipgen
, &tmp
->tt_t
);
537 tcp_freetemplate(struct tcptemp
*tmp
)
539 mpipe_free(&tcptemp_mpipe
, tmp
);
543 * Send a single message to the TCP at address specified by
544 * the given TCP/IP header. If m == NULL, then we make a copy
545 * of the tcpiphdr at ti and send directly to the addressed host.
546 * This is used to force keep alive messages out using the TCP
547 * template for a connection. If flags are given then we send
548 * a message back to the TCP which originated the * segment ti,
549 * and discard the mbuf containing it and any other attached mbufs.
551 * In any case the ack and sequence number of the transmitted
552 * segment are as specified by the parameters.
554 * NOTE: If m != NULL, then ti must point to *inside* the mbuf.
557 tcp_respond(struct tcpcb
*tp
, void *ipgen
, struct tcphdr
*th
, struct mbuf
*m
,
558 tcp_seq ack
, tcp_seq seq
, int flags
)
562 struct route
*ro
= NULL
;
564 struct ip
*ip
= ipgen
;
567 struct route_in6
*ro6
= NULL
;
568 struct route_in6 sro6
;
569 struct ip6_hdr
*ip6
= ipgen
;
570 boolean_t use_tmpro
= TRUE
;
572 boolean_t isipv6
= (IP_VHL_V(ip
->ip_vhl
) == 6);
574 const boolean_t isipv6
= FALSE
;
578 if (!(flags
& TH_RST
)) {
579 win
= ssb_space(&tp
->t_inpcb
->inp_socket
->so_rcv
);
582 if (win
> (long)TCP_MAXWIN
<< tp
->rcv_scale
)
583 win
= (long)TCP_MAXWIN
<< tp
->rcv_scale
;
586 * Don't use the route cache of a listen socket,
587 * it is not MPSAFE; use temporary route cache.
589 if (tp
->t_state
!= TCPS_LISTEN
) {
591 ro6
= &tp
->t_inpcb
->in6p_route
;
593 ro
= &tp
->t_inpcb
->inp_route
;
600 bzero(ro6
, sizeof *ro6
);
603 bzero(ro
, sizeof *ro
);
607 m
= m_gethdr(MB_DONTWAIT
, MT_HEADER
);
611 m
->m_data
+= max_linkhdr
;
613 bcopy(ip6
, mtod(m
, caddr_t
), sizeof(struct ip6_hdr
));
614 ip6
= mtod(m
, struct ip6_hdr
*);
615 nth
= (struct tcphdr
*)(ip6
+ 1);
617 bcopy(ip
, mtod(m
, caddr_t
), sizeof(struct ip
));
618 ip
= mtod(m
, struct ip
*);
619 nth
= (struct tcphdr
*)(ip
+ 1);
621 bcopy(th
, nth
, sizeof(struct tcphdr
));
626 m
->m_data
= (caddr_t
)ipgen
;
627 /* m_len is set later */
629 #define xchg(a, b, type) { type t; t = a; a = b; b = t; }
631 xchg(ip6
->ip6_dst
, ip6
->ip6_src
, struct in6_addr
);
632 nth
= (struct tcphdr
*)(ip6
+ 1);
634 xchg(ip
->ip_dst
.s_addr
, ip
->ip_src
.s_addr
, n_long
);
635 nth
= (struct tcphdr
*)(ip
+ 1);
639 * this is usually a case when an extension header
640 * exists between the IPv6 header and the
643 nth
->th_sport
= th
->th_sport
;
644 nth
->th_dport
= th
->th_dport
;
646 xchg(nth
->th_dport
, nth
->th_sport
, n_short
);
651 ip6
->ip6_vfc
= IPV6_VERSION
;
652 ip6
->ip6_nxt
= IPPROTO_TCP
;
653 ip6
->ip6_plen
= htons((u_short
)(sizeof(struct tcphdr
) + tlen
));
654 tlen
+= sizeof(struct ip6_hdr
) + sizeof(struct tcphdr
);
656 tlen
+= sizeof(struct tcpiphdr
);
658 ip
->ip_ttl
= ip_defttl
;
661 m
->m_pkthdr
.len
= tlen
;
662 m
->m_pkthdr
.rcvif
= NULL
;
663 nth
->th_seq
= htonl(seq
);
664 nth
->th_ack
= htonl(ack
);
666 nth
->th_off
= sizeof(struct tcphdr
) >> 2;
667 nth
->th_flags
= flags
;
669 nth
->th_win
= htons((u_short
) (win
>> tp
->rcv_scale
));
671 nth
->th_win
= htons((u_short
)win
);
675 nth
->th_sum
= in6_cksum(m
, IPPROTO_TCP
,
676 sizeof(struct ip6_hdr
),
677 tlen
- sizeof(struct ip6_hdr
));
678 ip6
->ip6_hlim
= in6_selecthlim(tp
? tp
->t_inpcb
: NULL
,
679 (ro6
&& ro6
->ro_rt
) ?
680 ro6
->ro_rt
->rt_ifp
: NULL
);
682 nth
->th_sum
= in_pseudo(ip
->ip_src
.s_addr
, ip
->ip_dst
.s_addr
,
683 htons((u_short
)(tlen
- sizeof(struct ip
) + ip
->ip_p
)));
684 m
->m_pkthdr
.csum_flags
= CSUM_TCP
;
685 m
->m_pkthdr
.csum_data
= offsetof(struct tcphdr
, th_sum
);
688 if (tp
== NULL
|| (tp
->t_inpcb
->inp_socket
->so_options
& SO_DEBUG
))
689 tcp_trace(TA_OUTPUT
, 0, tp
, mtod(m
, void *), th
, 0);
692 ip6_output(m
, NULL
, ro6
, ipflags
, NULL
, NULL
,
693 tp
? tp
->t_inpcb
: NULL
);
694 if ((ro6
== &sro6
) && (ro6
->ro_rt
!= NULL
)) {
699 ipflags
|= IP_DEBUGROUTE
;
700 ip_output(m
, NULL
, ro
, ipflags
, NULL
, tp
? tp
->t_inpcb
: NULL
);
701 if ((ro
== &sro
) && (ro
->ro_rt
!= NULL
)) {
709 * Create a new TCP control block, making an
710 * empty reassembly queue and hooking it to the argument
711 * protocol control block. The `inp' parameter must have
712 * come from the zone allocator set up in tcp_init().
715 tcp_newtcpcb(struct inpcb
*inp
)
720 boolean_t isipv6
= ((inp
->inp_vflag
& INP_IPV6
) != 0);
722 const boolean_t isipv6
= FALSE
;
725 it
= (struct inp_tp
*)inp
;
727 bzero(tp
, sizeof(struct tcpcb
));
728 LIST_INIT(&tp
->t_segq
);
729 tp
->t_maxseg
= tp
->t_maxopd
= isipv6
? tcp_v6mssdflt
: tcp_mssdflt
;
731 /* Set up our timeouts. */
732 tp
->tt_rexmt
= &it
->inp_tp_rexmt
;
733 tp
->tt_persist
= &it
->inp_tp_persist
;
734 tp
->tt_keep
= &it
->inp_tp_keep
;
735 tp
->tt_2msl
= &it
->inp_tp_2msl
;
736 tp
->tt_delack
= &it
->inp_tp_delack
;
740 * Zero out timer message. We don't create it here,
741 * since the current CPU may not be the owner of this
744 tp
->tt_msg
= &it
->inp_tp_timermsg
;
745 bzero(tp
->tt_msg
, sizeof(*tp
->tt_msg
));
748 tp
->t_flags
= (TF_REQ_SCALE
| TF_REQ_TSTMP
);
750 tp
->t_flags
|= TF_REQ_CC
;
751 tp
->t_inpcb
= inp
; /* XXX */
752 tp
->t_state
= TCPS_CLOSED
;
754 * Init srtt to TCPTV_SRTTBASE (0), so we can tell that we have no
755 * rtt estimate. Set rttvar so that srtt + 4 * rttvar gives
756 * reasonable initial retransmit time.
758 tp
->t_srtt
= TCPTV_SRTTBASE
;
760 ((TCPTV_RTOBASE
- TCPTV_SRTTBASE
) << TCP_RTTVAR_SHIFT
) / 4;
761 tp
->t_rttmin
= tcp_rexmit_min
;
762 tp
->t_rxtcur
= TCPTV_RTOBASE
;
763 tp
->snd_cwnd
= TCP_MAXWIN
<< TCP_MAX_WINSHIFT
;
764 tp
->snd_bwnd
= TCP_MAXWIN
<< TCP_MAX_WINSHIFT
;
765 tp
->snd_ssthresh
= TCP_MAXWIN
<< TCP_MAX_WINSHIFT
;
766 tp
->t_rcvtime
= ticks
;
768 * IPv4 TTL initialization is necessary for an IPv6 socket as well,
769 * because the socket may be bound to an IPv6 wildcard address,
770 * which may match an IPv4-mapped IPv6 address.
772 inp
->inp_ip_ttl
= ip_defttl
;
774 tcp_sack_tcpcb_init(tp
);
775 return (tp
); /* XXX */
779 * Drop a TCP connection, reporting the specified error.
780 * If connection is synchronized, then send a RST to peer.
783 tcp_drop(struct tcpcb
*tp
, int error
)
785 struct socket
*so
= tp
->t_inpcb
->inp_socket
;
787 if (TCPS_HAVERCVDSYN(tp
->t_state
)) {
788 tp
->t_state
= TCPS_CLOSED
;
790 tcpstat
.tcps_drops
++;
792 tcpstat
.tcps_conndrops
++;
793 if (error
== ETIMEDOUT
&& tp
->t_softerror
)
794 error
= tp
->t_softerror
;
795 so
->so_error
= error
;
796 return (tcp_close(tp
));
801 struct netmsg_remwildcard
{
802 struct netmsg nm_netmsg
;
803 struct inpcb
*nm_inp
;
804 struct inpcbinfo
*nm_pcbinfo
;
813 * Wildcard inpcb's on SMP boxes must be removed from all cpus before the
814 * inp can be detached. We do this by cycling through the cpus, ending up
815 * on the cpu controlling the inp last and then doing the disconnect.
818 in_pcbremwildcardhash_handler(struct netmsg
*msg0
)
820 struct netmsg_remwildcard
*msg
= (struct netmsg_remwildcard
*)msg0
;
823 cpu
= msg
->nm_pcbinfo
->cpu
;
825 if (cpu
== msg
->nm_inp
->inp_pcbinfo
->cpu
) {
826 /* note: detach removes any wildcard hash entry */
829 in6_pcbdetach(msg
->nm_inp
);
832 in_pcbdetach(msg
->nm_inp
);
833 lwkt_replymsg(&msg
->nm_netmsg
.nm_lmsg
, 0);
835 in_pcbremwildcardhash_oncpu(msg
->nm_inp
, msg
->nm_pcbinfo
);
836 cpu
= (cpu
+ 1) % ncpus2
;
837 msg
->nm_pcbinfo
= &tcbinfo
[cpu
];
838 lwkt_forwardmsg(tcp_cport(cpu
), &msg
->nm_netmsg
.nm_lmsg
);
845 * Close a TCP control block:
846 * discard all space held by the tcp
847 * discard internet protocol block
848 * wake up any sleepers
851 tcp_close(struct tcpcb
*tp
)
854 struct inpcb
*inp
= tp
->t_inpcb
;
855 struct socket
*so
= inp
->inp_socket
;
857 boolean_t dosavessthresh
;
862 boolean_t isipv6
= ((inp
->inp_vflag
& INP_IPV6
) != 0);
863 boolean_t isafinet6
= (INP_CHECK_SOCKAF(so
, AF_INET6
) != 0);
865 const boolean_t isipv6
= FALSE
;
869 * The tp is not instantly destroyed in the wildcard case. Setting
870 * the state to TCPS_TERMINATING will prevent the TCP stack from
871 * messing with it, though it should be noted that this change may
872 * not take effect on other cpus until we have chained the wildcard
875 * XXX we currently depend on the BGL to synchronize the tp->t_state
876 * update and prevent other tcp protocol threads from accepting new
877 * connections on the listen socket we might be trying to close down.
879 KKASSERT(tp
->t_state
!= TCPS_TERMINATING
);
880 tp
->t_state
= TCPS_TERMINATING
;
883 * Make sure that all of our timers are stopped before we
884 * delete the PCB. For listen TCP socket (tp->tt_msg == NULL),
885 * timers are never used. If timer message is never created
886 * (tp->tt_msg->tt_tcb == NULL), timers are never used too.
888 if (tp
->tt_msg
!= NULL
&& tp
->tt_msg
->tt_tcb
!= NULL
) {
889 tcp_callout_stop(tp
, tp
->tt_rexmt
);
890 tcp_callout_stop(tp
, tp
->tt_persist
);
891 tcp_callout_stop(tp
, tp
->tt_keep
);
892 tcp_callout_stop(tp
, tp
->tt_2msl
);
893 tcp_callout_stop(tp
, tp
->tt_delack
);
896 if (tp
->t_flags
& TF_ONOUTPUTQ
) {
897 KKASSERT(tp
->tt_cpu
== mycpu
->gd_cpuid
);
898 TAILQ_REMOVE(&tcpcbackq
[tp
->tt_cpu
], tp
, t_outputq
);
899 tp
->t_flags
&= ~TF_ONOUTPUTQ
;
903 * If we got enough samples through the srtt filter,
904 * save the rtt and rttvar in the routing entry.
905 * 'Enough' is arbitrarily defined as the 16 samples.
906 * 16 samples is enough for the srtt filter to converge
907 * to within 5% of the correct value; fewer samples and
908 * we could save a very bogus rtt.
910 * Don't update the default route's characteristics and don't
911 * update anything that the user "locked".
913 if (tp
->t_rttupdated
>= 16) {
917 struct sockaddr_in6
*sin6
;
919 if ((rt
= inp
->in6p_route
.ro_rt
) == NULL
)
921 sin6
= (struct sockaddr_in6
*)rt_key(rt
);
922 if (IN6_IS_ADDR_UNSPECIFIED(&sin6
->sin6_addr
))
925 if ((rt
= inp
->inp_route
.ro_rt
) == NULL
||
926 ((struct sockaddr_in
*)rt_key(rt
))->
927 sin_addr
.s_addr
== INADDR_ANY
)
930 if (!(rt
->rt_rmx
.rmx_locks
& RTV_RTT
)) {
931 i
= tp
->t_srtt
* (RTM_RTTUNIT
/ (hz
* TCP_RTT_SCALE
));
932 if (rt
->rt_rmx
.rmx_rtt
&& i
)
934 * filter this update to half the old & half
935 * the new values, converting scale.
936 * See route.h and tcp_var.h for a
937 * description of the scaling constants.
940 (rt
->rt_rmx
.rmx_rtt
+ i
) / 2;
942 rt
->rt_rmx
.rmx_rtt
= i
;
943 tcpstat
.tcps_cachedrtt
++;
945 if (!(rt
->rt_rmx
.rmx_locks
& RTV_RTTVAR
)) {
947 (RTM_RTTUNIT
/ (hz
* TCP_RTTVAR_SCALE
));
948 if (rt
->rt_rmx
.rmx_rttvar
&& i
)
949 rt
->rt_rmx
.rmx_rttvar
=
950 (rt
->rt_rmx
.rmx_rttvar
+ i
) / 2;
952 rt
->rt_rmx
.rmx_rttvar
= i
;
953 tcpstat
.tcps_cachedrttvar
++;
956 * The old comment here said:
957 * update the pipelimit (ssthresh) if it has been updated
958 * already or if a pipesize was specified & the threshhold
959 * got below half the pipesize. I.e., wait for bad news
960 * before we start updating, then update on both good
963 * But we want to save the ssthresh even if no pipesize is
964 * specified explicitly in the route, because such
965 * connections still have an implicit pipesize specified
966 * by the global tcp_sendspace. In the absence of a reliable
967 * way to calculate the pipesize, it will have to do.
969 i
= tp
->snd_ssthresh
;
970 if (rt
->rt_rmx
.rmx_sendpipe
!= 0)
971 dosavessthresh
= (i
< rt
->rt_rmx
.rmx_sendpipe
/2);
973 dosavessthresh
= (i
< so
->so_snd
.ssb_hiwat
/2);
974 if (dosavessthresh
||
975 (!(rt
->rt_rmx
.rmx_locks
& RTV_SSTHRESH
) && (i
!= 0) &&
976 (rt
->rt_rmx
.rmx_ssthresh
!= 0))) {
978 * convert the limit from user data bytes to
979 * packets then to packet data bytes.
981 i
= (i
+ tp
->t_maxseg
/ 2) / tp
->t_maxseg
;
986 sizeof(struct ip6_hdr
) + sizeof(struct tcphdr
) :
987 sizeof(struct tcpiphdr
));
988 if (rt
->rt_rmx
.rmx_ssthresh
)
989 rt
->rt_rmx
.rmx_ssthresh
=
990 (rt
->rt_rmx
.rmx_ssthresh
+ i
) / 2;
992 rt
->rt_rmx
.rmx_ssthresh
= i
;
993 tcpstat
.tcps_cachedssthresh
++;
998 /* free the reassembly queue, if any */
999 while((q
= LIST_FIRST(&tp
->t_segq
)) != NULL
) {
1000 LIST_REMOVE(q
, tqe_q
);
1005 /* throw away SACK blocks in scoreboard*/
1006 if (TCP_DO_SACK(tp
))
1007 tcp_sack_cleanup(&tp
->scb
);
1009 inp
->inp_ppcb
= NULL
;
1010 soisdisconnected(so
);
1012 tcp_destroy_timermsg(tp
);
1015 * Discard the inp. In the SMP case a wildcard inp's hash (created
1016 * by a listen socket or an INADDR_ANY udp socket) is replicated
1017 * for each protocol thread and must be removed in the context of
1018 * that thread. This is accomplished by chaining the message
1021 * If the inp is not wildcarded we simply detach, which will remove
1022 * the any hashes still present for this inp.
1025 if (inp
->inp_flags
& INP_WILDCARD_MP
) {
1026 struct netmsg_remwildcard
*msg
;
1028 cpu
= (inp
->inp_pcbinfo
->cpu
+ 1) % ncpus2
;
1029 msg
= kmalloc(sizeof(struct netmsg_remwildcard
),
1030 M_LWKTMSG
, M_INTWAIT
);
1031 netmsg_init(&msg
->nm_netmsg
, &netisr_afree_rport
, 0,
1032 in_pcbremwildcardhash_handler
);
1034 msg
->nm_isinet6
= isafinet6
;
1037 msg
->nm_pcbinfo
= &tcbinfo
[cpu
];
1038 lwkt_sendmsg(tcp_cport(cpu
), &msg
->nm_netmsg
.nm_lmsg
);
1042 /* note: detach removes any wildcard hash entry */
1050 tcpstat
.tcps_closed
++;
1054 static __inline
void
1055 tcp_drain_oncpu(struct inpcbhead
*head
)
1059 struct tseg_qent
*te
;
1061 LIST_FOREACH(inpb
, head
, inp_list
) {
1062 if (inpb
->inp_flags
& INP_PLACEMARKER
)
1064 if ((tcpb
= intotcpcb(inpb
))) {
1065 while ((te
= LIST_FIRST(&tcpb
->t_segq
)) != NULL
) {
1066 LIST_REMOVE(te
, tqe_q
);
1076 struct netmsg_tcp_drain
{
1077 struct netmsg nm_netmsg
;
1078 struct inpcbhead
*nm_head
;
1082 tcp_drain_handler(netmsg_t netmsg
)
1084 struct netmsg_tcp_drain
*nm
= (void *)netmsg
;
1086 tcp_drain_oncpu(nm
->nm_head
);
1087 lwkt_replymsg(&nm
->nm_netmsg
.nm_lmsg
, 0);
1102 * Walk the tcpbs, if existing, and flush the reassembly queue,
1103 * if there is one...
1104 * XXX: The "Net/3" implementation doesn't imply that the TCP
1105 * reassembly queue should be flushed, but in a situation
1106 * where we're really low on mbufs, this is potentially
1110 for (cpu
= 0; cpu
< ncpus2
; cpu
++) {
1111 struct netmsg_tcp_drain
*msg
;
1113 if (cpu
== mycpu
->gd_cpuid
) {
1114 tcp_drain_oncpu(&tcbinfo
[cpu
].pcblisthead
);
1116 msg
= kmalloc(sizeof(struct netmsg_tcp_drain
),
1117 M_LWKTMSG
, M_NOWAIT
);
1120 netmsg_init(&msg
->nm_netmsg
, &netisr_afree_rport
, 0,
1122 msg
->nm_head
= &tcbinfo
[cpu
].pcblisthead
;
1123 lwkt_sendmsg(tcp_cport(cpu
), &msg
->nm_netmsg
.nm_lmsg
);
1127 tcp_drain_oncpu(&tcbinfo
[0].pcblisthead
);
1132 * Notify a tcp user of an asynchronous error;
1133 * store error as soft error, but wake up user
1134 * (for now, won't do anything until can select for soft error).
1136 * Do not wake up user since there currently is no mechanism for
1137 * reporting soft errors (yet - a kqueue filter may be added).
1140 tcp_notify(struct inpcb
*inp
, int error
)
1142 struct tcpcb
*tp
= intotcpcb(inp
);
1145 * Ignore some errors if we are hooked up.
1146 * If connection hasn't completed, has retransmitted several times,
1147 * and receives a second error, give up now. This is better
1148 * than waiting a long time to establish a connection that
1149 * can never complete.
1151 if (tp
->t_state
== TCPS_ESTABLISHED
&&
1152 (error
== EHOSTUNREACH
|| error
== ENETUNREACH
||
1153 error
== EHOSTDOWN
)) {
1155 } else if (tp
->t_state
< TCPS_ESTABLISHED
&& tp
->t_rxtshift
> 3 &&
1157 tcp_drop(tp
, error
);
1159 tp
->t_softerror
= error
;
1161 wakeup(&so
->so_timeo
);
1168 tcp_pcblist(SYSCTL_HANDLER_ARGS
)
1171 struct inpcb
*marker
;
1181 * The process of preparing the TCB list is too time-consuming and
1182 * resource-intensive to repeat twice on every request.
1184 if (req
->oldptr
== NULL
) {
1185 for (ccpu
= 0; ccpu
< ncpus
; ++ccpu
) {
1186 gd
= globaldata_find(ccpu
);
1187 n
+= tcbinfo
[gd
->gd_cpuid
].ipi_count
;
1189 req
->oldidx
= (n
+ n
/8 + 10) * sizeof(struct xtcpcb
);
1193 if (req
->newptr
!= NULL
)
1196 marker
= kmalloc(sizeof(struct inpcb
), M_TEMP
, M_WAITOK
|M_ZERO
);
1197 marker
->inp_flags
|= INP_PLACEMARKER
;
1200 * OK, now we're committed to doing something. Run the inpcb list
1201 * for each cpu in the system and construct the output. Use a
1202 * list placemarker to deal with list changes occuring during
1203 * copyout blockages (but otherwise depend on being on the correct
1204 * cpu to avoid races).
1206 origcpu
= mycpu
->gd_cpuid
;
1207 for (ccpu
= 1; ccpu
<= ncpus
&& error
== 0; ++ccpu
) {
1213 cpu_id
= (origcpu
+ ccpu
) % ncpus
;
1214 if ((smp_active_mask
& (1 << cpu_id
)) == 0)
1216 rgd
= globaldata_find(cpu_id
);
1217 lwkt_setcpu_self(rgd
);
1219 gencnt
= tcbinfo
[cpu_id
].ipi_gencnt
;
1220 n
= tcbinfo
[cpu_id
].ipi_count
;
1222 LIST_INSERT_HEAD(&tcbinfo
[cpu_id
].pcblisthead
, marker
, inp_list
);
1224 while ((inp
= LIST_NEXT(marker
, inp_list
)) != NULL
&& i
< n
) {
1226 * process a snapshot of pcbs, ignoring placemarkers
1227 * and using our own to allow SYSCTL_OUT to block.
1229 LIST_REMOVE(marker
, inp_list
);
1230 LIST_INSERT_AFTER(inp
, marker
, inp_list
);
1232 if (inp
->inp_flags
& INP_PLACEMARKER
)
1234 if (inp
->inp_gencnt
> gencnt
)
1236 if (prison_xinpcb(req
->td
, inp
))
1239 xt
.xt_len
= sizeof xt
;
1240 bcopy(inp
, &xt
.xt_inp
, sizeof *inp
);
1241 inp_ppcb
= inp
->inp_ppcb
;
1242 if (inp_ppcb
!= NULL
)
1243 bcopy(inp_ppcb
, &xt
.xt_tp
, sizeof xt
.xt_tp
);
1245 bzero(&xt
.xt_tp
, sizeof xt
.xt_tp
);
1246 if (inp
->inp_socket
)
1247 sotoxsocket(inp
->inp_socket
, &xt
.xt_socket
);
1248 if ((error
= SYSCTL_OUT(req
, &xt
, sizeof xt
)) != 0)
1252 LIST_REMOVE(marker
, inp_list
);
1253 if (error
== 0 && i
< n
) {
1254 bzero(&xt
, sizeof xt
);
1255 xt
.xt_len
= sizeof xt
;
1257 error
= SYSCTL_OUT(req
, &xt
, sizeof xt
);
1266 * Make sure we are on the same cpu we were on originally, since
1267 * higher level callers expect this. Also don't pollute caches with
1268 * migrated userland data by (eventually) returning to userland
1269 * on a different cpu.
1271 lwkt_setcpu_self(globaldata_find(origcpu
));
1272 kfree(marker
, M_TEMP
);
1276 SYSCTL_PROC(_net_inet_tcp
, TCPCTL_PCBLIST
, pcblist
, CTLFLAG_RD
, 0, 0,
1277 tcp_pcblist
, "S,xtcpcb", "List of active TCP connections");
1280 tcp_getcred(SYSCTL_HANDLER_ARGS
)
1282 struct sockaddr_in addrs
[2];
1287 error
= priv_check(req
->td
, PRIV_ROOT
);
1290 error
= SYSCTL_IN(req
, addrs
, sizeof addrs
);
1294 cpu
= tcp_addrcpu(addrs
[1].sin_addr
.s_addr
, addrs
[1].sin_port
,
1295 addrs
[0].sin_addr
.s_addr
, addrs
[0].sin_port
);
1296 inp
= in_pcblookup_hash(&tcbinfo
[cpu
], addrs
[1].sin_addr
,
1297 addrs
[1].sin_port
, addrs
[0].sin_addr
, addrs
[0].sin_port
, 0, NULL
);
1298 if (inp
== NULL
|| inp
->inp_socket
== NULL
) {
1302 error
= SYSCTL_OUT(req
, inp
->inp_socket
->so_cred
, sizeof(struct ucred
));
1308 SYSCTL_PROC(_net_inet_tcp
, OID_AUTO
, getcred
, (CTLTYPE_OPAQUE
| CTLFLAG_RW
),
1309 0, 0, tcp_getcred
, "S,ucred", "Get the ucred of a TCP connection");
1313 tcp6_getcred(SYSCTL_HANDLER_ARGS
)
1315 struct sockaddr_in6 addrs
[2];
1318 boolean_t mapped
= FALSE
;
1320 error
= priv_check(req
->td
, PRIV_ROOT
);
1323 error
= SYSCTL_IN(req
, addrs
, sizeof addrs
);
1326 if (IN6_IS_ADDR_V4MAPPED(&addrs
[0].sin6_addr
)) {
1327 if (IN6_IS_ADDR_V4MAPPED(&addrs
[1].sin6_addr
))
1334 inp
= in_pcblookup_hash(&tcbinfo
[0],
1335 *(struct in_addr
*)&addrs
[1].sin6_addr
.s6_addr
[12],
1337 *(struct in_addr
*)&addrs
[0].sin6_addr
.s6_addr
[12],
1341 inp
= in6_pcblookup_hash(&tcbinfo
[0],
1342 &addrs
[1].sin6_addr
, addrs
[1].sin6_port
,
1343 &addrs
[0].sin6_addr
, addrs
[0].sin6_port
,
1346 if (inp
== NULL
|| inp
->inp_socket
== NULL
) {
1350 error
= SYSCTL_OUT(req
, inp
->inp_socket
->so_cred
, sizeof(struct ucred
));
1356 SYSCTL_PROC(_net_inet6_tcp6
, OID_AUTO
, getcred
, (CTLTYPE_OPAQUE
| CTLFLAG_RW
),
1358 tcp6_getcred
, "S,ucred", "Get the ucred of a TCP6 connection");
1361 struct netmsg_tcp_notify
{
1362 struct netmsg nm_nmsg
;
1363 void (*nm_notify
)(struct inpcb
*, int);
1364 struct in_addr nm_faddr
;
1369 tcp_notifyall_oncpu(struct netmsg
*netmsg
)
1371 struct netmsg_tcp_notify
*nmsg
= (struct netmsg_tcp_notify
*)netmsg
;
1374 in_pcbnotifyall(&tcbinfo
[mycpuid
].pcblisthead
, nmsg
->nm_faddr
,
1375 nmsg
->nm_arg
, nmsg
->nm_notify
);
1377 nextcpu
= mycpuid
+ 1;
1378 if (nextcpu
< ncpus2
)
1379 lwkt_forwardmsg(tcp_cport(nextcpu
), &netmsg
->nm_lmsg
);
1381 lwkt_replymsg(&netmsg
->nm_lmsg
, 0);
1385 tcp_ctlinput(int cmd
, struct sockaddr
*sa
, void *vip
)
1387 struct ip
*ip
= vip
;
1389 struct in_addr faddr
;
1392 void (*notify
)(struct inpcb
*, int) = tcp_notify
;
1396 if ((unsigned)cmd
>= PRC_NCMDS
|| inetctlerrmap
[cmd
] == 0) {
1400 faddr
= ((struct sockaddr_in
*)sa
)->sin_addr
;
1401 if (sa
->sa_family
!= AF_INET
|| faddr
.s_addr
== INADDR_ANY
)
1404 arg
= inetctlerrmap
[cmd
];
1405 if (cmd
== PRC_QUENCH
) {
1406 notify
= tcp_quench
;
1407 } else if (icmp_may_rst
&&
1408 (cmd
== PRC_UNREACH_ADMIN_PROHIB
||
1409 cmd
== PRC_UNREACH_PORT
||
1410 cmd
== PRC_TIMXCEED_INTRANS
) &&
1412 notify
= tcp_drop_syn_sent
;
1413 } else if (cmd
== PRC_MSGSIZE
) {
1414 struct icmp
*icmp
= (struct icmp
*)
1415 ((caddr_t
)ip
- offsetof(struct icmp
, icmp_ip
));
1417 arg
= ntohs(icmp
->icmp_nextmtu
);
1418 notify
= tcp_mtudisc
;
1419 } else if (PRC_IS_REDIRECT(cmd
)) {
1421 notify
= in_rtchange
;
1422 } else if (cmd
== PRC_HOSTDEAD
) {
1428 th
= (struct tcphdr
*)((caddr_t
)ip
+
1429 (IP_VHL_HL(ip
->ip_vhl
) << 2));
1430 cpu
= tcp_addrcpu(faddr
.s_addr
, th
->th_dport
,
1431 ip
->ip_src
.s_addr
, th
->th_sport
);
1432 inp
= in_pcblookup_hash(&tcbinfo
[cpu
], faddr
, th
->th_dport
,
1433 ip
->ip_src
, th
->th_sport
, 0, NULL
);
1434 if ((inp
!= NULL
) && (inp
->inp_socket
!= NULL
)) {
1435 icmpseq
= htonl(th
->th_seq
);
1436 tp
= intotcpcb(inp
);
1437 if (SEQ_GEQ(icmpseq
, tp
->snd_una
) &&
1438 SEQ_LT(icmpseq
, tp
->snd_max
))
1439 (*notify
)(inp
, arg
);
1441 struct in_conninfo inc
;
1443 inc
.inc_fport
= th
->th_dport
;
1444 inc
.inc_lport
= th
->th_sport
;
1445 inc
.inc_faddr
= faddr
;
1446 inc
.inc_laddr
= ip
->ip_src
;
1450 syncache_unreach(&inc
, th
);
1454 struct netmsg_tcp_notify nmsg
;
1456 KKASSERT(&curthread
->td_msgport
== cpu_portfn(0));
1457 netmsg_init(&nmsg
.nm_nmsg
, &curthread
->td_msgport
, 0,
1458 tcp_notifyall_oncpu
);
1459 nmsg
.nm_faddr
= faddr
;
1461 nmsg
.nm_notify
= notify
;
1463 lwkt_domsg(tcp_cport(0), &nmsg
.nm_nmsg
.nm_lmsg
, 0);
1469 tcp6_ctlinput(int cmd
, struct sockaddr
*sa
, void *d
)
1472 void (*notify
) (struct inpcb
*, int) = tcp_notify
;
1473 struct ip6_hdr
*ip6
;
1475 struct ip6ctlparam
*ip6cp
= NULL
;
1476 const struct sockaddr_in6
*sa6_src
= NULL
;
1478 struct tcp_portonly
{
1484 if (sa
->sa_family
!= AF_INET6
||
1485 sa
->sa_len
!= sizeof(struct sockaddr_in6
))
1489 if (cmd
== PRC_QUENCH
)
1490 notify
= tcp_quench
;
1491 else if (cmd
== PRC_MSGSIZE
) {
1492 struct ip6ctlparam
*ip6cp
= d
;
1493 struct icmp6_hdr
*icmp6
= ip6cp
->ip6c_icmp6
;
1495 arg
= ntohl(icmp6
->icmp6_mtu
);
1496 notify
= tcp_mtudisc
;
1497 } else if (!PRC_IS_REDIRECT(cmd
) &&
1498 ((unsigned)cmd
> PRC_NCMDS
|| inet6ctlerrmap
[cmd
] == 0)) {
1502 /* if the parameter is from icmp6, decode it. */
1504 ip6cp
= (struct ip6ctlparam
*)d
;
1506 ip6
= ip6cp
->ip6c_ip6
;
1507 off
= ip6cp
->ip6c_off
;
1508 sa6_src
= ip6cp
->ip6c_src
;
1512 off
= 0; /* fool gcc */
1517 struct in_conninfo inc
;
1519 * XXX: We assume that when IPV6 is non NULL,
1520 * M and OFF are valid.
1523 /* check if we can safely examine src and dst ports */
1524 if (m
->m_pkthdr
.len
< off
+ sizeof *thp
)
1527 bzero(&th
, sizeof th
);
1528 m_copydata(m
, off
, sizeof *thp
, (caddr_t
)&th
);
1530 in6_pcbnotify(&tcbinfo
[0].pcblisthead
, sa
, th
.th_dport
,
1531 (struct sockaddr
*)ip6cp
->ip6c_src
,
1532 th
.th_sport
, cmd
, arg
, notify
);
1534 inc
.inc_fport
= th
.th_dport
;
1535 inc
.inc_lport
= th
.th_sport
;
1536 inc
.inc6_faddr
= ((struct sockaddr_in6
*)sa
)->sin6_addr
;
1537 inc
.inc6_laddr
= ip6cp
->ip6c_src
->sin6_addr
;
1539 syncache_unreach(&inc
, &th
);
1541 in6_pcbnotify(&tcbinfo
[0].pcblisthead
, sa
, 0,
1542 (const struct sockaddr
*)sa6_src
, 0, cmd
, arg
, notify
);
1547 * Following is where TCP initial sequence number generation occurs.
1549 * There are two places where we must use initial sequence numbers:
1550 * 1. In SYN-ACK packets.
1551 * 2. In SYN packets.
1553 * All ISNs for SYN-ACK packets are generated by the syncache. See
1554 * tcp_syncache.c for details.
1556 * The ISNs in SYN packets must be monotonic; TIME_WAIT recycling
1557 * depends on this property. In addition, these ISNs should be
1558 * unguessable so as to prevent connection hijacking. To satisfy
1559 * the requirements of this situation, the algorithm outlined in
1560 * RFC 1948 is used to generate sequence numbers.
1562 * Implementation details:
1564 * Time is based off the system timer, and is corrected so that it
1565 * increases by one megabyte per second. This allows for proper
1566 * recycling on high speed LANs while still leaving over an hour
1569 * net.inet.tcp.isn_reseed_interval controls the number of seconds
1570 * between seeding of isn_secret. This is normally set to zero,
1571 * as reseeding should not be necessary.
1575 #define ISN_BYTES_PER_SECOND 1048576
1577 u_char isn_secret
[32];
1578 int isn_last_reseed
;
1582 tcp_new_isn(struct tcpcb
*tp
)
1584 u_int32_t md5_buffer
[4];
1587 /* Seed if this is the first use, reseed if requested. */
1588 if ((isn_last_reseed
== 0) || ((tcp_isn_reseed_interval
> 0) &&
1589 (((u_int
)isn_last_reseed
+ (u_int
)tcp_isn_reseed_interval
*hz
)
1591 read_random_unlimited(&isn_secret
, sizeof isn_secret
);
1592 isn_last_reseed
= ticks
;
1595 /* Compute the md5 hash and return the ISN. */
1597 MD5Update(&isn_ctx
, (u_char
*)&tp
->t_inpcb
->inp_fport
, sizeof(u_short
));
1598 MD5Update(&isn_ctx
, (u_char
*)&tp
->t_inpcb
->inp_lport
, sizeof(u_short
));
1600 if (tp
->t_inpcb
->inp_vflag
& INP_IPV6
) {
1601 MD5Update(&isn_ctx
, (u_char
*) &tp
->t_inpcb
->in6p_faddr
,
1602 sizeof(struct in6_addr
));
1603 MD5Update(&isn_ctx
, (u_char
*) &tp
->t_inpcb
->in6p_laddr
,
1604 sizeof(struct in6_addr
));
1608 MD5Update(&isn_ctx
, (u_char
*) &tp
->t_inpcb
->inp_faddr
,
1609 sizeof(struct in_addr
));
1610 MD5Update(&isn_ctx
, (u_char
*) &tp
->t_inpcb
->inp_laddr
,
1611 sizeof(struct in_addr
));
1613 MD5Update(&isn_ctx
, (u_char
*) &isn_secret
, sizeof(isn_secret
));
1614 MD5Final((u_char
*) &md5_buffer
, &isn_ctx
);
1615 new_isn
= (tcp_seq
) md5_buffer
[0];
1616 new_isn
+= ticks
* (ISN_BYTES_PER_SECOND
/ hz
);
1621 * When a source quench is received, close congestion window
1622 * to one segment. We will gradually open it again as we proceed.
1625 tcp_quench(struct inpcb
*inp
, int error
)
1627 struct tcpcb
*tp
= intotcpcb(inp
);
1630 tp
->snd_cwnd
= tp
->t_maxseg
;
1636 * When a specific ICMP unreachable message is received and the
1637 * connection state is SYN-SENT, drop the connection. This behavior
1638 * is controlled by the icmp_may_rst sysctl.
1641 tcp_drop_syn_sent(struct inpcb
*inp
, int error
)
1643 struct tcpcb
*tp
= intotcpcb(inp
);
1645 if ((tp
!= NULL
) && (tp
->t_state
== TCPS_SYN_SENT
))
1646 tcp_drop(tp
, error
);
1650 * When a `need fragmentation' ICMP is received, update our idea of the MSS
1651 * based on the new value in the route. Also nudge TCP to send something,
1652 * since we know the packet we just sent was dropped.
1653 * This duplicates some code in the tcp_mss() function in tcp_input.c.
1656 tcp_mtudisc(struct inpcb
*inp
, int mtu
)
1658 struct tcpcb
*tp
= intotcpcb(inp
);
1660 struct socket
*so
= inp
->inp_socket
;
1663 boolean_t isipv6
= ((tp
->t_inpcb
->inp_vflag
& INP_IPV6
) != 0);
1665 const boolean_t isipv6
= FALSE
;
1672 * If no MTU is provided in the ICMP message, use the
1673 * next lower likely value, as specified in RFC 1191.
1678 oldmtu
= tp
->t_maxopd
+
1680 sizeof(struct ip6_hdr
) + sizeof(struct tcphdr
) :
1681 sizeof(struct tcpiphdr
));
1682 mtu
= ip_next_mtu(oldmtu
, 0);
1686 rt
= tcp_rtlookup6(&inp
->inp_inc
);
1688 rt
= tcp_rtlookup(&inp
->inp_inc
);
1690 struct rmxp_tao
*taop
= rmx_taop(rt
->rt_rmx
);
1692 if (rt
->rt_rmx
.rmx_mtu
!= 0 && rt
->rt_rmx
.rmx_mtu
< mtu
)
1693 mtu
= rt
->rt_rmx
.rmx_mtu
;
1697 sizeof(struct ip6_hdr
) + sizeof(struct tcphdr
) :
1698 sizeof(struct tcpiphdr
));
1701 * XXX - The following conditional probably violates the TCP
1702 * spec. The problem is that, since we don't know the
1703 * other end's MSS, we are supposed to use a conservative
1704 * default. But, if we do that, then MTU discovery will
1705 * never actually take place, because the conservative
1706 * default is much less than the MTUs typically seen
1707 * on the Internet today. For the moment, we'll sweep
1708 * this under the carpet.
1710 * The conservative default might not actually be a problem
1711 * if the only case this occurs is when sending an initial
1712 * SYN with options and data to a host we've never talked
1713 * to before. Then, they will reply with an MSS value which
1714 * will get recorded and the new parameters should get
1715 * recomputed. For Further Study.
1717 if (taop
->tao_mssopt
!= 0 && taop
->tao_mssopt
< maxopd
)
1718 maxopd
= taop
->tao_mssopt
;
1722 sizeof(struct ip6_hdr
) + sizeof(struct tcphdr
) :
1723 sizeof(struct tcpiphdr
));
1725 if (tp
->t_maxopd
<= maxopd
)
1727 tp
->t_maxopd
= maxopd
;
1730 if ((tp
->t_flags
& (TF_REQ_TSTMP
| TF_RCVD_TSTMP
| TF_NOOPT
)) ==
1731 (TF_REQ_TSTMP
| TF_RCVD_TSTMP
))
1732 mss
-= TCPOLEN_TSTAMP_APPA
;
1734 if ((tp
->t_flags
& (TF_REQ_CC
| TF_RCVD_CC
| TF_NOOPT
)) ==
1735 (TF_REQ_CC
| TF_RCVD_CC
))
1736 mss
-= TCPOLEN_CC_APPA
;
1738 /* round down to multiple of MCLBYTES */
1739 #if (MCLBYTES & (MCLBYTES - 1)) == 0 /* test if MCLBYTES power of 2 */
1741 mss
&= ~(MCLBYTES
- 1);
1744 mss
= (mss
/ MCLBYTES
) * MCLBYTES
;
1747 if (so
->so_snd
.ssb_hiwat
< mss
)
1748 mss
= so
->so_snd
.ssb_hiwat
;
1752 tp
->snd_nxt
= tp
->snd_una
;
1754 tcpstat
.tcps_mturesent
++;
1758 * Look-up the routing entry to the peer of this inpcb. If no route
1759 * is found and it cannot be allocated the return NULL. This routine
1760 * is called by TCP routines that access the rmx structure and by tcp_mss
1761 * to get the interface MTU.
1764 tcp_rtlookup(struct in_conninfo
*inc
)
1766 struct route
*ro
= &inc
->inc_route
;
1768 if (ro
->ro_rt
== NULL
|| !(ro
->ro_rt
->rt_flags
& RTF_UP
)) {
1769 /* No route yet, so try to acquire one */
1770 if (inc
->inc_faddr
.s_addr
!= INADDR_ANY
) {
1772 * unused portions of the structure MUST be zero'd
1773 * out because rtalloc() treats it as opaque data
1775 bzero(&ro
->ro_dst
, sizeof(struct sockaddr_in
));
1776 ro
->ro_dst
.sa_family
= AF_INET
;
1777 ro
->ro_dst
.sa_len
= sizeof(struct sockaddr_in
);
1778 ((struct sockaddr_in
*) &ro
->ro_dst
)->sin_addr
=
1788 tcp_rtlookup6(struct in_conninfo
*inc
)
1790 struct route_in6
*ro6
= &inc
->inc6_route
;
1792 if (ro6
->ro_rt
== NULL
|| !(ro6
->ro_rt
->rt_flags
& RTF_UP
)) {
1793 /* No route yet, so try to acquire one */
1794 if (!IN6_IS_ADDR_UNSPECIFIED(&inc
->inc6_faddr
)) {
1796 * unused portions of the structure MUST be zero'd
1797 * out because rtalloc() treats it as opaque data
1799 bzero(&ro6
->ro_dst
, sizeof(struct sockaddr_in6
));
1800 ro6
->ro_dst
.sin6_family
= AF_INET6
;
1801 ro6
->ro_dst
.sin6_len
= sizeof(struct sockaddr_in6
);
1802 ro6
->ro_dst
.sin6_addr
= inc
->inc6_faddr
;
1803 rtalloc((struct route
*)ro6
);
1806 return (ro6
->ro_rt
);
1811 /* compute ESP/AH header size for TCP, including outer IP header. */
1813 ipsec_hdrsiz_tcp(struct tcpcb
*tp
)
1821 if ((tp
== NULL
) || ((inp
= tp
->t_inpcb
) == NULL
))
1823 MGETHDR(m
, MB_DONTWAIT
, MT_DATA
);
1828 if (inp
->inp_vflag
& INP_IPV6
) {
1829 struct ip6_hdr
*ip6
= mtod(m
, struct ip6_hdr
*);
1831 th
= (struct tcphdr
*)(ip6
+ 1);
1832 m
->m_pkthdr
.len
= m
->m_len
=
1833 sizeof(struct ip6_hdr
) + sizeof(struct tcphdr
);
1834 tcp_fillheaders(tp
, ip6
, th
);
1835 hdrsiz
= ipsec6_hdrsiz(m
, IPSEC_DIR_OUTBOUND
, inp
);
1839 ip
= mtod(m
, struct ip
*);
1840 th
= (struct tcphdr
*)(ip
+ 1);
1841 m
->m_pkthdr
.len
= m
->m_len
= sizeof(struct tcpiphdr
);
1842 tcp_fillheaders(tp
, ip
, th
);
1843 hdrsiz
= ipsec4_hdrsiz(m
, IPSEC_DIR_OUTBOUND
, inp
);
1852 * Return a pointer to the cached information about the remote host.
1853 * The cached information is stored in the protocol specific part of
1854 * the route metrics.
1857 tcp_gettaocache(struct in_conninfo
*inc
)
1862 if (inc
->inc_isipv6
)
1863 rt
= tcp_rtlookup6(inc
);
1866 rt
= tcp_rtlookup(inc
);
1868 /* Make sure this is a host route and is up. */
1870 (rt
->rt_flags
& (RTF_UP
| RTF_HOST
)) != (RTF_UP
| RTF_HOST
))
1873 return (rmx_taop(rt
->rt_rmx
));
1877 * Clear all the TAO cache entries, called from tcp_init.
1880 * This routine is just an empty one, because we assume that the routing
1881 * routing tables are initialized at the same time when TCP, so there is
1882 * nothing in the cache left over.
1885 tcp_cleartaocache(void)
1890 * TCP BANDWIDTH DELAY PRODUCT WINDOW LIMITING
1892 * This code attempts to calculate the bandwidth-delay product as a
1893 * means of determining the optimal window size to maximize bandwidth,
1894 * minimize RTT, and avoid the over-allocation of buffers on interfaces and
1895 * routers. This code also does a fairly good job keeping RTTs in check
1896 * across slow links like modems. We implement an algorithm which is very
1897 * similar (but not meant to be) TCP/Vegas. The code operates on the
1898 * transmitter side of a TCP connection and so only effects the transmit
1899 * side of the connection.
1901 * BACKGROUND: TCP makes no provision for the management of buffer space
1902 * at the end points or at the intermediate routers and switches. A TCP
1903 * stream, whether using NewReno or not, will eventually buffer as
1904 * many packets as it is able and the only reason this typically works is
1905 * due to the fairly small default buffers made available for a connection
1906 * (typicaly 16K or 32K). As machines use larger windows and/or window
1907 * scaling it is now fairly easy for even a single TCP connection to blow-out
1908 * all available buffer space not only on the local interface, but on
1909 * intermediate routers and switches as well. NewReno makes a misguided
1910 * attempt to 'solve' this problem by waiting for an actual failure to occur,
1911 * then backing off, then steadily increasing the window again until another
1912 * failure occurs, ad-infinitum. This results in terrible oscillation that
1913 * is only made worse as network loads increase and the idea of intentionally
1914 * blowing out network buffers is, frankly, a terrible way to manage network
1917 * It is far better to limit the transmit window prior to the failure
1918 * condition being achieved. There are two general ways to do this: First
1919 * you can 'scan' through different transmit window sizes and locate the
1920 * point where the RTT stops increasing, indicating that you have filled the
1921 * pipe, then scan backwards until you note that RTT stops decreasing, then
1922 * repeat ad-infinitum. This method works in principle but has severe
1923 * implementation issues due to RTT variances, timer granularity, and
1924 * instability in the algorithm which can lead to many false positives and
1925 * create oscillations as well as interact badly with other TCP streams
1926 * implementing the same algorithm.
1928 * The second method is to limit the window to the bandwidth delay product
1929 * of the link. This is the method we implement. RTT variances and our
1930 * own manipulation of the congestion window, bwnd, can potentially
1931 * destabilize the algorithm. For this reason we have to stabilize the
1932 * elements used to calculate the window. We do this by using the minimum
1933 * observed RTT, the long term average of the observed bandwidth, and
1934 * by adding two segments worth of slop. It isn't perfect but it is able
1935 * to react to changing conditions and gives us a very stable basis on
1936 * which to extend the algorithm.
1939 tcp_xmit_bandwidth_limit(struct tcpcb
*tp
, tcp_seq ack_seq
)
1947 * If inflight_enable is disabled in the middle of a tcp connection,
1948 * make sure snd_bwnd is effectively disabled.
1950 if (!tcp_inflight_enable
) {
1951 tp
->snd_bwnd
= TCP_MAXWIN
<< TCP_MAX_WINSHIFT
;
1952 tp
->snd_bandwidth
= 0;
1957 * Validate the delta time. If a connection is new or has been idle
1958 * a long time we have to reset the bandwidth calculator.
1961 delta_ticks
= save_ticks
- tp
->t_bw_rtttime
;
1962 if (tp
->t_bw_rtttime
== 0 || delta_ticks
< 0 || delta_ticks
> hz
* 10) {
1963 tp
->t_bw_rtttime
= ticks
;
1964 tp
->t_bw_rtseq
= ack_seq
;
1965 if (tp
->snd_bandwidth
== 0)
1966 tp
->snd_bandwidth
= tcp_inflight_min
;
1969 if (delta_ticks
== 0)
1973 * Sanity check, plus ignore pure window update acks.
1975 if ((int)(ack_seq
- tp
->t_bw_rtseq
) <= 0)
1979 * Figure out the bandwidth. Due to the tick granularity this
1980 * is a very rough number and it MUST be averaged over a fairly
1981 * long period of time. XXX we need to take into account a link
1982 * that is not using all available bandwidth, but for now our
1983 * slop will ramp us up if this case occurs and the bandwidth later
1986 bw
= (int64_t)(ack_seq
- tp
->t_bw_rtseq
) * hz
/ delta_ticks
;
1987 tp
->t_bw_rtttime
= save_ticks
;
1988 tp
->t_bw_rtseq
= ack_seq
;
1989 bw
= ((int64_t)tp
->snd_bandwidth
* 15 + bw
) >> 4;
1991 tp
->snd_bandwidth
= bw
;
1994 * Calculate the semi-static bandwidth delay product, plus two maximal
1995 * segments. The additional slop puts us squarely in the sweet
1996 * spot and also handles the bandwidth run-up case. Without the
1997 * slop we could be locking ourselves into a lower bandwidth.
1999 * Situations Handled:
2000 * (1) Prevents over-queueing of packets on LANs, especially on
2001 * high speed LANs, allowing larger TCP buffers to be
2002 * specified, and also does a good job preventing
2003 * over-queueing of packets over choke points like modems
2004 * (at least for the transmit side).
2006 * (2) Is able to handle changing network loads (bandwidth
2007 * drops so bwnd drops, bandwidth increases so bwnd
2010 * (3) Theoretically should stabilize in the face of multiple
2011 * connections implementing the same algorithm (this may need
2014 * (4) Stability value (defaults to 20 = 2 maximal packets) can
2015 * be adjusted with a sysctl but typically only needs to be on
2016 * very slow connections. A value no smaller then 5 should
2017 * be used, but only reduce this default if you have no other
2021 #define USERTT ((tp->t_srtt + tp->t_rttbest) / 2)
2022 bwnd
= (int64_t)bw
* USERTT
/ (hz
<< TCP_RTT_SHIFT
) +
2023 tcp_inflight_stab
* (int)tp
->t_maxseg
/ 10;
2026 if (tcp_inflight_debug
> 0) {
2028 if ((u_int
)(ticks
- ltime
) >= hz
/ tcp_inflight_debug
) {
2030 kprintf("%p bw %ld rttbest %d srtt %d bwnd %ld\n",
2031 tp
, bw
, tp
->t_rttbest
, tp
->t_srtt
, bwnd
);
2034 if ((long)bwnd
< tcp_inflight_min
)
2035 bwnd
= tcp_inflight_min
;
2036 if (bwnd
> tcp_inflight_max
)
2037 bwnd
= tcp_inflight_max
;
2038 if ((long)bwnd
< tp
->t_maxseg
* 2)
2039 bwnd
= tp
->t_maxseg
* 2;
2040 tp
->snd_bwnd
= bwnd
;