1/*
2 * Copyright (c) 1982, 1986, 1988, 1990, 1993, 1995
3 * The Regents of the University of California. All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. All advertising materials mentioning features or use of this software
14 * must display the following acknowledgement:
15 * This product includes software developed by the University of
16 * California, Berkeley and its contributors.
17 * 4. Neither the name of the University nor the names of its contributors
18 * may be used to endorse or promote products derived from this software
19 * without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 *
33 * @(#)tcp_subr.c 8.2 (Berkeley) 5/24/95
| 1/*
2 * Copyright (c) 1982, 1986, 1988, 1990, 1993, 1995
3 * The Regents of the University of California. All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. All advertising materials mentioning features or use of this software
14 * must display the following acknowledgement:
15 * This product includes software developed by the University of
16 * California, Berkeley and its contributors.
17 * 4. Neither the name of the University nor the names of its contributors
18 * may be used to endorse or promote products derived from this software
19 * without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 *
33 * @(#)tcp_subr.c 8.2 (Berkeley) 5/24/95
|
34 * $FreeBSD: head/sys/netinet/tcp_timewait.c 112009 2003-03-08 22:06:20Z jlemon $
| 34 * $FreeBSD: head/sys/netinet/tcp_timewait.c 113345 2003-04-10 20:33:10Z rwatson $
|
35 */
36
37#include "opt_compat.h"
38#include "opt_inet6.h"
39#include "opt_ipsec.h"
40#include "opt_mac.h"
41#include "opt_tcpdebug.h"
42
43#include <sys/param.h>
44#include <sys/systm.h>
45#include <sys/callout.h>
46#include <sys/kernel.h>
47#include <sys/sysctl.h>
48#include <sys/mac.h>
49#include <sys/malloc.h>
50#include <sys/mbuf.h>
51#ifdef INET6
52#include <sys/domain.h>
53#endif
54#include <sys/proc.h>
55#include <sys/socket.h>
56#include <sys/socketvar.h>
57#include <sys/protosw.h>
58#include <sys/random.h>
59
60#include <vm/uma.h>
61
62#include <net/route.h>
63#include <net/if.h>
64
65#include <netinet/in.h>
66#include <netinet/in_systm.h>
67#include <netinet/ip.h>
68#ifdef INET6
69#include <netinet/ip6.h>
70#endif
71#include <netinet/in_pcb.h>
72#ifdef INET6
73#include <netinet6/in6_pcb.h>
74#endif
75#include <netinet/in_var.h>
76#include <netinet/ip_var.h>
77#ifdef INET6
78#include <netinet6/ip6_var.h>
79#endif
80#include <netinet/tcp.h>
81#include <netinet/tcp_fsm.h>
82#include <netinet/tcp_seq.h>
83#include <netinet/tcp_timer.h>
84#include <netinet/tcp_var.h>
85#ifdef INET6
86#include <netinet6/tcp6_var.h>
87#endif
88#include <netinet/tcpip.h>
89#ifdef TCPDEBUG
90#include <netinet/tcp_debug.h>
91#endif
92#include <netinet6/ip6protosw.h>
93
94#ifdef IPSEC
95#include <netinet6/ipsec.h>
96#ifdef INET6
97#include <netinet6/ipsec6.h>
98#endif
99#endif /*IPSEC*/
100
101#ifdef FAST_IPSEC
102#include <netipsec/ipsec.h>
103#ifdef INET6
104#include <netipsec/ipsec6.h>
105#endif
106#define IPSEC
107#endif /*FAST_IPSEC*/
108
109#include <machine/in_cksum.h>
110#include <sys/md5.h>
111
112int tcp_mssdflt = TCP_MSS;
113SYSCTL_INT(_net_inet_tcp, TCPCTL_MSSDFLT, mssdflt, CTLFLAG_RW,
114 &tcp_mssdflt , 0, "Default TCP Maximum Segment Size");
115
116#ifdef INET6
117int tcp_v6mssdflt = TCP6_MSS;
118SYSCTL_INT(_net_inet_tcp, TCPCTL_V6MSSDFLT, v6mssdflt,
119 CTLFLAG_RW, &tcp_v6mssdflt , 0,
120 "Default TCP Maximum Segment Size for IPv6");
121#endif
122
123#if 0
124static int tcp_rttdflt = TCPTV_SRTTDFLT / PR_SLOWHZ;
125SYSCTL_INT(_net_inet_tcp, TCPCTL_RTTDFLT, rttdflt, CTLFLAG_RW,
126 &tcp_rttdflt , 0, "Default maximum TCP Round Trip Time");
127#endif
128
129int tcp_do_rfc1323 = 1;
130SYSCTL_INT(_net_inet_tcp, TCPCTL_DO_RFC1323, rfc1323, CTLFLAG_RW,
131 &tcp_do_rfc1323 , 0, "Enable rfc1323 (high performance TCP) extensions");
132
133int tcp_do_rfc1644 = 0;
134SYSCTL_INT(_net_inet_tcp, TCPCTL_DO_RFC1644, rfc1644, CTLFLAG_RW,
135 &tcp_do_rfc1644 , 0, "Enable rfc1644 (TTCP) extensions");
136
137static int tcp_tcbhashsize = 0;
138SYSCTL_INT(_net_inet_tcp, OID_AUTO, tcbhashsize, CTLFLAG_RD,
139 &tcp_tcbhashsize, 0, "Size of TCP control-block hashtable");
140
141static int do_tcpdrain = 1;
142SYSCTL_INT(_net_inet_tcp, OID_AUTO, do_tcpdrain, CTLFLAG_RW, &do_tcpdrain, 0,
143 "Enable tcp_drain routine for extra help when low on mbufs");
144
145SYSCTL_INT(_net_inet_tcp, OID_AUTO, pcbcount, CTLFLAG_RD,
146 &tcbinfo.ipi_count, 0, "Number of active PCBs");
147
148static int icmp_may_rst = 1;
149SYSCTL_INT(_net_inet_tcp, OID_AUTO, icmp_may_rst, CTLFLAG_RW, &icmp_may_rst, 0,
150 "Certain ICMP unreachable messages may abort connections in SYN_SENT");
151
152static int tcp_isn_reseed_interval = 0;
153SYSCTL_INT(_net_inet_tcp, OID_AUTO, isn_reseed_interval, CTLFLAG_RW,
154 &tcp_isn_reseed_interval, 0, "Seconds between reseeding of ISN secret");
155
156/*
157 * TCP bandwidth limiting sysctls. Note that the default lower bound of
158 * 1024 exists only for debugging. A good production default would be
159 * something like 6100.
160 */
161static int tcp_inflight_enable = 0;
162SYSCTL_INT(_net_inet_tcp, OID_AUTO, inflight_enable, CTLFLAG_RW,
163 &tcp_inflight_enable, 0, "Enable automatic TCP inflight data limiting");
164
165static int tcp_inflight_debug = 0;
166SYSCTL_INT(_net_inet_tcp, OID_AUTO, inflight_debug, CTLFLAG_RW,
167 &tcp_inflight_debug, 0, "Debug TCP inflight calculations");
168
169static int tcp_inflight_min = 6144;
170SYSCTL_INT(_net_inet_tcp, OID_AUTO, inflight_min, CTLFLAG_RW,
171 &tcp_inflight_min, 0, "Lower-bound for TCP inflight window");
172
173static int tcp_inflight_max = TCP_MAXWIN << TCP_MAX_WINSHIFT;
174SYSCTL_INT(_net_inet_tcp, OID_AUTO, inflight_max, CTLFLAG_RW,
175 &tcp_inflight_max, 0, "Upper-bound for TCP inflight window");
176static int tcp_inflight_stab = 20;
177SYSCTL_INT(_net_inet_tcp, OID_AUTO, inflight_stab, CTLFLAG_RW,
178 &tcp_inflight_stab, 0, "Inflight Algorithm Stabilization 20 = 2 packets");
179
180static void tcp_cleartaocache(void);
181static struct inpcb *tcp_notify(struct inpcb *, int);
182static void tcp_discardcb(struct tcpcb *);
183
184/*
185 * Target size of TCP PCB hash tables. Must be a power of two.
186 *
187 * Note that this can be overridden by the kernel environment
188 * variable net.inet.tcp.tcbhashsize
189 */
190#ifndef TCBHASHSIZE
191#define TCBHASHSIZE 512
192#endif
193
194/*
195 * XXX
196 * Callouts should be moved into struct tcp directly. They are currently
197 * separate becuase the tcpcb structure is exported to userland for sysctl
198 * parsing purposes, which do not know about callouts.
199 */
200struct tcpcb_mem {
201 struct tcpcb tcb;
202 struct callout tcpcb_mem_rexmt, tcpcb_mem_persist, tcpcb_mem_keep;
203 struct callout tcpcb_mem_2msl, tcpcb_mem_delack;
204};
205
206static uma_zone_t tcpcb_zone;
207static uma_zone_t tcptw_zone;
208
209/*
210 * Tcp initialization
211 */
212void
213tcp_init()
214{
215 int hashsize = TCBHASHSIZE;
216
217 tcp_ccgen = 1;
218 tcp_cleartaocache();
219
220 tcp_delacktime = TCPTV_DELACK;
221 tcp_keepinit = TCPTV_KEEP_INIT;
222 tcp_keepidle = TCPTV_KEEP_IDLE;
223 tcp_keepintvl = TCPTV_KEEPINTVL;
224 tcp_maxpersistidle = TCPTV_KEEP_IDLE;
225 tcp_msl = TCPTV_MSL;
226 tcp_rexmit_min = TCPTV_MIN;
227 tcp_rexmit_slop = TCPTV_CPU_VAR;
228
229 INP_INFO_LOCK_INIT(&tcbinfo, "tcp");
230 LIST_INIT(&tcb);
231 tcbinfo.listhead = &tcb;
232 TUNABLE_INT_FETCH("net.inet.tcp.tcbhashsize", &hashsize);
233 if (!powerof2(hashsize)) {
234 printf("WARNING: TCB hash size not a power of 2\n");
235 hashsize = 512; /* safe default */
236 }
237 tcp_tcbhashsize = hashsize;
238 tcbinfo.hashbase = hashinit(hashsize, M_PCB, &tcbinfo.hashmask);
239 tcbinfo.porthashbase = hashinit(hashsize, M_PCB,
240 &tcbinfo.porthashmask);
241 tcbinfo.ipi_zone = uma_zcreate("inpcb", sizeof(struct inpcb),
242 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE);
243 uma_zone_set_max(tcbinfo.ipi_zone, maxsockets);
244#ifdef INET6
245#define TCP_MINPROTOHDR (sizeof(struct ip6_hdr) + sizeof(struct tcphdr))
246#else /* INET6 */
247#define TCP_MINPROTOHDR (sizeof(struct tcpiphdr))
248#endif /* INET6 */
249 if (max_protohdr < TCP_MINPROTOHDR)
250 max_protohdr = TCP_MINPROTOHDR;
251 if (max_linkhdr + TCP_MINPROTOHDR > MHLEN)
252 panic("tcp_init");
253#undef TCP_MINPROTOHDR
254 /*
255 * These have to be type stable for the benefit of the timers.
256 */
257 tcpcb_zone = uma_zcreate("tcpcb", sizeof(struct tcpcb_mem),
258 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE);
259 uma_zone_set_max(tcpcb_zone, maxsockets);
260 tcptw_zone = uma_zcreate("tcptw", sizeof(struct tcptw),
261 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE);
262 uma_zone_set_max(tcptw_zone, maxsockets);
263 tcp_timer_init();
264 syncache_init();
265}
266
267/*
268 * Fill in the IP and TCP headers for an outgoing packet, given the tcpcb.
269 * tcp_template used to store this data in mbufs, but we now recopy it out
270 * of the tcpcb each time to conserve mbufs.
271 */
272void
273tcpip_fillheaders(inp, ip_ptr, tcp_ptr)
274 struct inpcb *inp;
275 void *ip_ptr;
276 void *tcp_ptr;
277{
278 struct tcphdr *th = (struct tcphdr *)tcp_ptr;
279
280#ifdef INET6
281 if ((inp->inp_vflag & INP_IPV6) != 0) {
282 struct ip6_hdr *ip6;
283
284 ip6 = (struct ip6_hdr *)ip_ptr;
285 ip6->ip6_flow = (ip6->ip6_flow & ~IPV6_FLOWINFO_MASK) |
286 (inp->in6p_flowinfo & IPV6_FLOWINFO_MASK);
287 ip6->ip6_vfc = (ip6->ip6_vfc & ~IPV6_VERSION_MASK) |
288 (IPV6_VERSION & IPV6_VERSION_MASK);
289 ip6->ip6_nxt = IPPROTO_TCP;
290 ip6->ip6_plen = sizeof(struct tcphdr);
291 ip6->ip6_src = inp->in6p_laddr;
292 ip6->ip6_dst = inp->in6p_faddr;
293 } else
294#endif
295 {
296 struct ip *ip;
297
298 ip = (struct ip *)ip_ptr;
299 ip->ip_v = IPVERSION;
300 ip->ip_hl = 5;
301 ip->ip_tos = inp->inp_ip_tos;
302 ip->ip_len = 0;
303 ip->ip_id = 0;
304 ip->ip_off = 0;
305 ip->ip_ttl = inp->inp_ip_ttl;
306 ip->ip_sum = 0;
307 ip->ip_p = IPPROTO_TCP;
308 ip->ip_src = inp->inp_laddr;
309 ip->ip_dst = inp->inp_faddr;
310 }
311 th->th_sport = inp->inp_lport;
312 th->th_dport = inp->inp_fport;
313 th->th_seq = 0;
314 th->th_ack = 0;
315 th->th_x2 = 0;
316 th->th_off = 5;
317 th->th_flags = 0;
318 th->th_win = 0;
319 th->th_urp = 0;
320 th->th_sum = 0; /* in_pseudo() is called later for ipv4 */
321}
322
323/*
324 * Create template to be used to send tcp packets on a connection.
325 * Allocates an mbuf and fills in a skeletal tcp/ip header. The only
326 * use for this function is in keepalives, which use tcp_respond.
327 */
328struct tcptemp *
329tcpip_maketemplate(inp)
330 struct inpcb *inp;
331{
332 struct mbuf *m;
333 struct tcptemp *n;
334
335 m = m_get(M_DONTWAIT, MT_HEADER);
336 if (m == NULL)
337 return (0);
338 m->m_len = sizeof(struct tcptemp);
339 n = mtod(m, struct tcptemp *);
340
341 tcpip_fillheaders(inp, (void *)&n->tt_ipgen, (void *)&n->tt_t);
342 return (n);
343}
344
345/*
346 * Send a single message to the TCP at address specified by
347 * the given TCP/IP header. If m == 0, then we make a copy
348 * of the tcpiphdr at ti and send directly to the addressed host.
349 * This is used to force keep alive messages out using the TCP
350 * template for a connection. If flags are given then we send
351 * a message back to the TCP which originated the * segment ti,
352 * and discard the mbuf containing it and any other attached mbufs.
353 *
354 * In any case the ack and sequence number of the transmitted
355 * segment are as specified by the parameters.
356 *
357 * NOTE: If m != NULL, then ti must point to *inside* the mbuf.
358 */
359void
360tcp_respond(tp, ipgen, th, m, ack, seq, flags)
361 struct tcpcb *tp;
362 void *ipgen;
363 register struct tcphdr *th;
364 register struct mbuf *m;
365 tcp_seq ack, seq;
366 int flags;
367{
368 register int tlen;
369 int win = 0;
370 struct route *ro = 0;
371 struct route sro;
372 struct ip *ip;
373 struct tcphdr *nth;
374#ifdef INET6
375 struct route_in6 *ro6 = 0;
376 struct route_in6 sro6;
377 struct ip6_hdr *ip6;
378 int isipv6;
379#endif /* INET6 */
380 int ipflags = 0;
381
382 KASSERT(tp != NULL || m != NULL, ("tcp_respond: tp and m both NULL"));
383
384#ifdef INET6
385 isipv6 = ((struct ip *)ipgen)->ip_v == 6;
386 ip6 = ipgen;
387#endif /* INET6 */
388 ip = ipgen;
389
390 if (tp) {
391 if (!(flags & TH_RST)) {
392 win = sbspace(&tp->t_inpcb->inp_socket->so_rcv);
393 if (win > (long)TCP_MAXWIN << tp->rcv_scale)
394 win = (long)TCP_MAXWIN << tp->rcv_scale;
395 }
396#ifdef INET6
397 if (isipv6)
398 ro6 = &tp->t_inpcb->in6p_route;
399 else
400#endif /* INET6 */
401 ro = &tp->t_inpcb->inp_route;
402 } else {
403#ifdef INET6
404 if (isipv6) {
405 ro6 = &sro6;
406 bzero(ro6, sizeof *ro6);
407 } else
408#endif /* INET6 */
409 {
410 ro = &sro;
411 bzero(ro, sizeof *ro);
412 }
413 }
414 if (m == 0) {
415 m = m_gethdr(M_DONTWAIT, MT_HEADER);
416 if (m == NULL)
417 return;
418 tlen = 0;
419 m->m_data += max_linkhdr;
420#ifdef INET6
421 if (isipv6) {
422 bcopy((caddr_t)ip6, mtod(m, caddr_t),
423 sizeof(struct ip6_hdr));
424 ip6 = mtod(m, struct ip6_hdr *);
425 nth = (struct tcphdr *)(ip6 + 1);
426 } else
427#endif /* INET6 */
428 {
429 bcopy((caddr_t)ip, mtod(m, caddr_t), sizeof(struct ip));
430 ip = mtod(m, struct ip *);
431 nth = (struct tcphdr *)(ip + 1);
432 }
433 bcopy((caddr_t)th, (caddr_t)nth, sizeof(struct tcphdr));
434 flags = TH_ACK;
435 } else {
436 m_freem(m->m_next);
437 m->m_next = 0;
438 m->m_data = (caddr_t)ipgen;
439 /* m_len is set later */
440 tlen = 0;
441#define xchg(a,b,type) { type t; t=a; a=b; b=t; }
442#ifdef INET6
443 if (isipv6) {
444 xchg(ip6->ip6_dst, ip6->ip6_src, struct in6_addr);
445 nth = (struct tcphdr *)(ip6 + 1);
446 } else
447#endif /* INET6 */
448 {
449 xchg(ip->ip_dst.s_addr, ip->ip_src.s_addr, n_long);
450 nth = (struct tcphdr *)(ip + 1);
451 }
452 if (th != nth) {
453 /*
454 * this is usually a case when an extension header
455 * exists between the IPv6 header and the
456 * TCP header.
457 */
458 nth->th_sport = th->th_sport;
459 nth->th_dport = th->th_dport;
460 }
461 xchg(nth->th_dport, nth->th_sport, n_short);
462#undef xchg
463 }
464#ifdef INET6
465 if (isipv6) {
466 ip6->ip6_flow = 0;
467 ip6->ip6_vfc = IPV6_VERSION;
468 ip6->ip6_nxt = IPPROTO_TCP;
469 ip6->ip6_plen = htons((u_short)(sizeof (struct tcphdr) +
470 tlen));
471 tlen += sizeof (struct ip6_hdr) + sizeof (struct tcphdr);
472 } else
473#endif
474 {
475 tlen += sizeof (struct tcpiphdr);
476 ip->ip_len = tlen;
477 ip->ip_ttl = ip_defttl;
478 }
479 m->m_len = tlen;
480 m->m_pkthdr.len = tlen;
481 m->m_pkthdr.rcvif = (struct ifnet *) 0;
482#ifdef MAC
483 if (tp != NULL && tp->t_inpcb != NULL) {
484 /*
485 * Packet is associated with a socket, so allow the
486 * label of the response to reflect the socket label.
487 */
488 mac_create_mbuf_from_socket(tp->t_inpcb->inp_socket, m);
489 } else {
490 /*
491 * XXXMAC: This will need to call a mac function that
492 * modifies the mbuf label in place for TCP datagrams
493 * not associated with a PCB.
494 */
495 }
496#endif
497 nth->th_seq = htonl(seq);
498 nth->th_ack = htonl(ack);
499 nth->th_x2 = 0;
500 nth->th_off = sizeof (struct tcphdr) >> 2;
501 nth->th_flags = flags;
502 if (tp)
503 nth->th_win = htons((u_short) (win >> tp->rcv_scale));
504 else
505 nth->th_win = htons((u_short)win);
506 nth->th_urp = 0;
507#ifdef INET6
508 if (isipv6) {
509 nth->th_sum = 0;
510 nth->th_sum = in6_cksum(m, IPPROTO_TCP,
511 sizeof(struct ip6_hdr),
512 tlen - sizeof(struct ip6_hdr));
513 ip6->ip6_hlim = in6_selecthlim(tp ? tp->t_inpcb : NULL,
514 ro6 && ro6->ro_rt ?
515 ro6->ro_rt->rt_ifp :
516 NULL);
517 } else
518#endif /* INET6 */
519 {
520 nth->th_sum = in_pseudo(ip->ip_src.s_addr, ip->ip_dst.s_addr,
521 htons((u_short)(tlen - sizeof(struct ip) + ip->ip_p)));
522 m->m_pkthdr.csum_flags = CSUM_TCP;
523 m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum);
524 }
525#ifdef TCPDEBUG
526 if (tp == NULL || (tp->t_inpcb->inp_socket->so_options & SO_DEBUG))
527 tcp_trace(TA_OUTPUT, 0, tp, mtod(m, void *), th, 0);
528#endif
529#ifdef INET6
530 if (isipv6) {
531 (void)ip6_output(m, NULL, ro6, ipflags, NULL, NULL,
532 tp ? tp->t_inpcb : NULL);
533 if (ro6 == &sro6 && ro6->ro_rt) {
534 RTFREE(ro6->ro_rt);
535 ro6->ro_rt = NULL;
536 }
537 } else
538#endif /* INET6 */
539 {
540 (void) ip_output(m, NULL, ro, ipflags, NULL, tp ? tp->t_inpcb : NULL);
541 if (ro == &sro && ro->ro_rt) {
542 RTFREE(ro->ro_rt);
543 ro->ro_rt = NULL;
544 }
545 }
546}
547
548/*
549 * Create a new TCP control block, making an
550 * empty reassembly queue and hooking it to the argument
551 * protocol control block. The `inp' parameter must have
552 * come from the zone allocator set up in tcp_init().
553 */
554struct tcpcb *
555tcp_newtcpcb(inp)
556 struct inpcb *inp;
557{
558 struct tcpcb_mem *tm;
559 struct tcpcb *tp;
560#ifdef INET6
561 int isipv6 = (inp->inp_vflag & INP_IPV6) != 0;
562#endif /* INET6 */
563
564 tm = uma_zalloc(tcpcb_zone, M_NOWAIT | M_ZERO);
565 if (tm == NULL)
566 return (NULL);
567 tp = &tm->tcb;
568 /* LIST_INIT(&tp->t_segq); */ /* XXX covered by M_ZERO */
569 tp->t_maxseg = tp->t_maxopd =
570#ifdef INET6
571 isipv6 ? tcp_v6mssdflt :
572#endif /* INET6 */
573 tcp_mssdflt;
574
575 /* Set up our timeouts. */
576 callout_init(tp->tt_rexmt = &tm->tcpcb_mem_rexmt, 0);
577 callout_init(tp->tt_persist = &tm->tcpcb_mem_persist, 0);
578 callout_init(tp->tt_keep = &tm->tcpcb_mem_keep, 0);
579 callout_init(tp->tt_2msl = &tm->tcpcb_mem_2msl, 0);
580 callout_init(tp->tt_delack = &tm->tcpcb_mem_delack, 0);
581
582 if (tcp_do_rfc1323)
583 tp->t_flags = (TF_REQ_SCALE|TF_REQ_TSTMP);
584 if (tcp_do_rfc1644)
585 tp->t_flags |= TF_REQ_CC;
586 tp->t_inpcb = inp; /* XXX */
587 /*
588 * Init srtt to TCPTV_SRTTBASE (0), so we can tell that we have no
589 * rtt estimate. Set rttvar so that srtt + 4 * rttvar gives
590 * reasonable initial retransmit time.
591 */
592 tp->t_srtt = TCPTV_SRTTBASE;
593 tp->t_rttvar = ((TCPTV_RTOBASE - TCPTV_SRTTBASE) << TCP_RTTVAR_SHIFT) / 4;
594 tp->t_rttmin = tcp_rexmit_min;
595 tp->t_rxtcur = TCPTV_RTOBASE;
596 tp->snd_cwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT;
597 tp->snd_bwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT;
598 tp->snd_ssthresh = TCP_MAXWIN << TCP_MAX_WINSHIFT;
599 tp->t_rcvtime = ticks;
600 tp->t_bw_rtttime = ticks;
601 /*
602 * IPv4 TTL initialization is necessary for an IPv6 socket as well,
603 * because the socket may be bound to an IPv6 wildcard address,
604 * which may match an IPv4-mapped IPv6 address.
605 */
606 inp->inp_ip_ttl = ip_defttl;
607 inp->inp_ppcb = (caddr_t)tp;
608 return (tp); /* XXX */
609}
610
611/*
612 * Drop a TCP connection, reporting
613 * the specified error. If connection is synchronized,
614 * then send a RST to peer.
615 */
616struct tcpcb *
617tcp_drop(tp, errno)
618 register struct tcpcb *tp;
619 int errno;
620{
621 struct socket *so = tp->t_inpcb->inp_socket;
622
623 if (TCPS_HAVERCVDSYN(tp->t_state)) {
624 tp->t_state = TCPS_CLOSED;
625 (void) tcp_output(tp);
626 tcpstat.tcps_drops++;
627 } else
628 tcpstat.tcps_conndrops++;
629 if (errno == ETIMEDOUT && tp->t_softerror)
630 errno = tp->t_softerror;
631 so->so_error = errno;
632 return (tcp_close(tp));
633}
634
635static void
636tcp_discardcb(tp)
637 struct tcpcb *tp;
638{
639 struct tseg_qent *q;
640 struct inpcb *inp = tp->t_inpcb;
641 struct socket *so = inp->inp_socket;
642#ifdef INET6
643 int isipv6 = (inp->inp_vflag & INP_IPV6) != 0;
644#endif /* INET6 */
645 struct rtentry *rt;
646 int dosavessthresh;
647
648 /*
649 * Make sure that all of our timers are stopped before we
650 * delete the PCB.
651 */
652 callout_stop(tp->tt_rexmt);
653 callout_stop(tp->tt_persist);
654 callout_stop(tp->tt_keep);
655 callout_stop(tp->tt_2msl);
656 callout_stop(tp->tt_delack);
657
658 /*
659 * If we got enough samples through the srtt filter,
660 * save the rtt and rttvar in the routing entry.
661 * 'Enough' is arbitrarily defined as the 16 samples.
662 * 16 samples is enough for the srtt filter to converge
663 * to within 5% of the correct value; fewer samples and
664 * we could save a very bogus rtt.
665 *
666 * Don't update the default route's characteristics and don't
667 * update anything that the user "locked".
668 */
669 if (tp->t_rttupdated >= 16) {
670 register u_long i = 0;
671#ifdef INET6
672 if (isipv6) {
673 struct sockaddr_in6 *sin6;
674
675 if ((rt = inp->in6p_route.ro_rt) == NULL)
676 goto no_valid_rt;
677 sin6 = (struct sockaddr_in6 *)rt_key(rt);
678 if (IN6_IS_ADDR_UNSPECIFIED(&sin6->sin6_addr))
679 goto no_valid_rt;
680 }
681 else
682#endif /* INET6 */
683 if ((rt = inp->inp_route.ro_rt) == NULL ||
684 ((struct sockaddr_in *)rt_key(rt))->sin_addr.s_addr
685 == INADDR_ANY)
686 goto no_valid_rt;
687
688 if ((rt->rt_rmx.rmx_locks & RTV_RTT) == 0) {
689 i = tp->t_srtt *
690 (RTM_RTTUNIT / (hz * TCP_RTT_SCALE));
691 if (rt->rt_rmx.rmx_rtt && i)
692 /*
693 * filter this update to half the old & half
694 * the new values, converting scale.
695 * See route.h and tcp_var.h for a
696 * description of the scaling constants.
697 */
698 rt->rt_rmx.rmx_rtt =
699 (rt->rt_rmx.rmx_rtt + i) / 2;
700 else
701 rt->rt_rmx.rmx_rtt = i;
702 tcpstat.tcps_cachedrtt++;
703 }
704 if ((rt->rt_rmx.rmx_locks & RTV_RTTVAR) == 0) {
705 i = tp->t_rttvar *
706 (RTM_RTTUNIT / (hz * TCP_RTTVAR_SCALE));
707 if (rt->rt_rmx.rmx_rttvar && i)
708 rt->rt_rmx.rmx_rttvar =
709 (rt->rt_rmx.rmx_rttvar + i) / 2;
710 else
711 rt->rt_rmx.rmx_rttvar = i;
712 tcpstat.tcps_cachedrttvar++;
713 }
714 /*
715 * The old comment here said:
716 * update the pipelimit (ssthresh) if it has been updated
717 * already or if a pipesize was specified & the threshhold
718 * got below half the pipesize. I.e., wait for bad news
719 * before we start updating, then update on both good
720 * and bad news.
721 *
722 * But we want to save the ssthresh even if no pipesize is
723 * specified explicitly in the route, because such
724 * connections still have an implicit pipesize specified
725 * by the global tcp_sendspace. In the absence of a reliable
726 * way to calculate the pipesize, it will have to do.
727 */
728 i = tp->snd_ssthresh;
729 if (rt->rt_rmx.rmx_sendpipe != 0)
730 dosavessthresh = (i < rt->rt_rmx.rmx_sendpipe / 2);
731 else
732 dosavessthresh = (i < so->so_snd.sb_hiwat / 2);
733 if (((rt->rt_rmx.rmx_locks & RTV_SSTHRESH) == 0 &&
734 i != 0 && rt->rt_rmx.rmx_ssthresh != 0)
735 || dosavessthresh) {
736 /*
737 * convert the limit from user data bytes to
738 * packets then to packet data bytes.
739 */
740 i = (i + tp->t_maxseg / 2) / tp->t_maxseg;
741 if (i < 2)
742 i = 2;
743 i *= (u_long)(tp->t_maxseg +
744#ifdef INET6
745 (isipv6 ? sizeof (struct ip6_hdr) +
746 sizeof (struct tcphdr) :
747#endif
748 sizeof (struct tcpiphdr)
749#ifdef INET6
750 )
751#endif
752 );
753 if (rt->rt_rmx.rmx_ssthresh)
754 rt->rt_rmx.rmx_ssthresh =
755 (rt->rt_rmx.rmx_ssthresh + i) / 2;
756 else
757 rt->rt_rmx.rmx_ssthresh = i;
758 tcpstat.tcps_cachedssthresh++;
759 }
760 }
761 no_valid_rt:
762 /* free the reassembly queue, if any */
763 while ((q = LIST_FIRST(&tp->t_segq)) != NULL) {
764 LIST_REMOVE(q, tqe_q);
765 m_freem(q->tqe_m);
766 FREE(q, M_TSEGQ);
767 }
768 inp->inp_ppcb = NULL;
769 tp->t_inpcb = NULL;
770 uma_zfree(tcpcb_zone, tp);
771 soisdisconnected(so);
772}
773
774/*
775 * Close a TCP control block:
776 * discard all space held by the tcp
777 * discard internet protocol block
778 * wake up any sleepers
779 */
780struct tcpcb *
781tcp_close(tp)
782 struct tcpcb *tp;
783{
784 struct inpcb *inp = tp->t_inpcb;
785#ifdef INET6
786 struct socket *so = inp->inp_socket;
787#endif
788
789 tcp_discardcb(tp);
790#ifdef INET6
791 if (INP_CHECK_SOCKAF(so, AF_INET6))
792 in6_pcbdetach(inp);
793 else
794#endif
795 in_pcbdetach(inp);
796 tcpstat.tcps_closed++;
797 return ((struct tcpcb *)0);
798}
799
800void
801tcp_drain()
802{
803 if (do_tcpdrain)
804 {
805 struct inpcb *inpb;
806 struct tcpcb *tcpb;
807 struct tseg_qent *te;
808
809 /*
810 * Walk the tcpbs, if existing, and flush the reassembly queue,
811 * if there is one...
812 * XXX: The "Net/3" implementation doesn't imply that the TCP
813 * reassembly queue should be flushed, but in a situation
814 * where we're really low on mbufs, this is potentially
815 * usefull.
816 */
817 INP_INFO_RLOCK(&tcbinfo);
818 LIST_FOREACH(inpb, tcbinfo.listhead, inp_list) {
819 if (inpb->inp_vflag & INP_TIMEWAIT)
820 continue;
821 INP_LOCK(inpb);
822 if ((tcpb = intotcpcb(inpb))) {
823 while ((te = LIST_FIRST(&tcpb->t_segq))
824 != NULL) {
825 LIST_REMOVE(te, tqe_q);
826 m_freem(te->tqe_m);
827 FREE(te, M_TSEGQ);
828 }
829 }
830 INP_UNLOCK(inpb);
831 }
832 INP_INFO_RUNLOCK(&tcbinfo);
833 }
834}
835
836/*
837 * Notify a tcp user of an asynchronous error;
838 * store error as soft error, but wake up user
839 * (for now, won't do anything until can select for soft error).
840 *
841 * Do not wake up user since there currently is no mechanism for
842 * reporting soft errors (yet - a kqueue filter may be added).
843 */
844static struct inpcb *
845tcp_notify(inp, error)
846 struct inpcb *inp;
847 int error;
848{
849 struct tcpcb *tp = (struct tcpcb *)inp->inp_ppcb;
850
851 /*
852 * Ignore some errors if we are hooked up.
853 * If connection hasn't completed, has retransmitted several times,
854 * and receives a second error, give up now. This is better
855 * than waiting a long time to establish a connection that
856 * can never complete.
857 */
858 if (tp->t_state == TCPS_ESTABLISHED &&
859 (error == EHOSTUNREACH || error == ENETUNREACH ||
860 error == EHOSTDOWN)) {
861 return inp;
862 } else if (tp->t_state < TCPS_ESTABLISHED && tp->t_rxtshift > 3 &&
863 tp->t_softerror) {
864 tcp_drop(tp, error);
865 return (struct inpcb *)0;
866 } else {
867 tp->t_softerror = error;
868 return inp;
869 }
870#if 0
871 wakeup( &so->so_timeo);
872 sorwakeup(so);
873 sowwakeup(so);
874#endif
875}
876
877static int
878tcp_pcblist(SYSCTL_HANDLER_ARGS)
879{
880 int error, i, n, s;
881 struct inpcb *inp, **inp_list;
882 inp_gen_t gencnt;
883 struct xinpgen xig;
884
885 /*
886 * The process of preparing the TCB list is too time-consuming and
887 * resource-intensive to repeat twice on every request.
888 */
889 if (req->oldptr == 0) {
890 n = tcbinfo.ipi_count;
891 req->oldidx = 2 * (sizeof xig)
892 + (n + n/8) * sizeof(struct xtcpcb);
893 return 0;
894 }
895
896 if (req->newptr != 0)
897 return EPERM;
898
899 /*
900 * OK, now we're committed to doing something.
901 */
902 s = splnet();
903 INP_INFO_RLOCK(&tcbinfo);
904 gencnt = tcbinfo.ipi_gencnt;
905 n = tcbinfo.ipi_count;
906 INP_INFO_RUNLOCK(&tcbinfo);
907 splx(s);
908
909 sysctl_wire_old_buffer(req, 2 * (sizeof xig)
910 + n * sizeof(struct xtcpcb));
911
912 xig.xig_len = sizeof xig;
913 xig.xig_count = n;
914 xig.xig_gen = gencnt;
915 xig.xig_sogen = so_gencnt;
916 error = SYSCTL_OUT(req, &xig, sizeof xig);
917 if (error)
918 return error;
919
920 inp_list = malloc(n * sizeof *inp_list, M_TEMP, M_WAITOK);
921 if (inp_list == 0)
922 return ENOMEM;
923
924 s = splnet();
925 INP_INFO_RLOCK(&tcbinfo);
926 for (inp = LIST_FIRST(tcbinfo.listhead), i = 0; inp && i < n;
927 inp = LIST_NEXT(inp, inp_list)) {
928 INP_LOCK(inp);
| 35 */
36
37#include "opt_compat.h"
38#include "opt_inet6.h"
39#include "opt_ipsec.h"
40#include "opt_mac.h"
41#include "opt_tcpdebug.h"
42
43#include <sys/param.h>
44#include <sys/systm.h>
45#include <sys/callout.h>
46#include <sys/kernel.h>
47#include <sys/sysctl.h>
48#include <sys/mac.h>
49#include <sys/malloc.h>
50#include <sys/mbuf.h>
51#ifdef INET6
52#include <sys/domain.h>
53#endif
54#include <sys/proc.h>
55#include <sys/socket.h>
56#include <sys/socketvar.h>
57#include <sys/protosw.h>
58#include <sys/random.h>
59
60#include <vm/uma.h>
61
62#include <net/route.h>
63#include <net/if.h>
64
65#include <netinet/in.h>
66#include <netinet/in_systm.h>
67#include <netinet/ip.h>
68#ifdef INET6
69#include <netinet/ip6.h>
70#endif
71#include <netinet/in_pcb.h>
72#ifdef INET6
73#include <netinet6/in6_pcb.h>
74#endif
75#include <netinet/in_var.h>
76#include <netinet/ip_var.h>
77#ifdef INET6
78#include <netinet6/ip6_var.h>
79#endif
80#include <netinet/tcp.h>
81#include <netinet/tcp_fsm.h>
82#include <netinet/tcp_seq.h>
83#include <netinet/tcp_timer.h>
84#include <netinet/tcp_var.h>
85#ifdef INET6
86#include <netinet6/tcp6_var.h>
87#endif
88#include <netinet/tcpip.h>
89#ifdef TCPDEBUG
90#include <netinet/tcp_debug.h>
91#endif
92#include <netinet6/ip6protosw.h>
93
94#ifdef IPSEC
95#include <netinet6/ipsec.h>
96#ifdef INET6
97#include <netinet6/ipsec6.h>
98#endif
99#endif /*IPSEC*/
100
101#ifdef FAST_IPSEC
102#include <netipsec/ipsec.h>
103#ifdef INET6
104#include <netipsec/ipsec6.h>
105#endif
106#define IPSEC
107#endif /*FAST_IPSEC*/
108
109#include <machine/in_cksum.h>
110#include <sys/md5.h>
111
112int tcp_mssdflt = TCP_MSS;
113SYSCTL_INT(_net_inet_tcp, TCPCTL_MSSDFLT, mssdflt, CTLFLAG_RW,
114 &tcp_mssdflt , 0, "Default TCP Maximum Segment Size");
115
116#ifdef INET6
117int tcp_v6mssdflt = TCP6_MSS;
118SYSCTL_INT(_net_inet_tcp, TCPCTL_V6MSSDFLT, v6mssdflt,
119 CTLFLAG_RW, &tcp_v6mssdflt , 0,
120 "Default TCP Maximum Segment Size for IPv6");
121#endif
122
123#if 0
124static int tcp_rttdflt = TCPTV_SRTTDFLT / PR_SLOWHZ;
125SYSCTL_INT(_net_inet_tcp, TCPCTL_RTTDFLT, rttdflt, CTLFLAG_RW,
126 &tcp_rttdflt , 0, "Default maximum TCP Round Trip Time");
127#endif
128
129int tcp_do_rfc1323 = 1;
130SYSCTL_INT(_net_inet_tcp, TCPCTL_DO_RFC1323, rfc1323, CTLFLAG_RW,
131 &tcp_do_rfc1323 , 0, "Enable rfc1323 (high performance TCP) extensions");
132
133int tcp_do_rfc1644 = 0;
134SYSCTL_INT(_net_inet_tcp, TCPCTL_DO_RFC1644, rfc1644, CTLFLAG_RW,
135 &tcp_do_rfc1644 , 0, "Enable rfc1644 (TTCP) extensions");
136
137static int tcp_tcbhashsize = 0;
138SYSCTL_INT(_net_inet_tcp, OID_AUTO, tcbhashsize, CTLFLAG_RD,
139 &tcp_tcbhashsize, 0, "Size of TCP control-block hashtable");
140
141static int do_tcpdrain = 1;
142SYSCTL_INT(_net_inet_tcp, OID_AUTO, do_tcpdrain, CTLFLAG_RW, &do_tcpdrain, 0,
143 "Enable tcp_drain routine for extra help when low on mbufs");
144
145SYSCTL_INT(_net_inet_tcp, OID_AUTO, pcbcount, CTLFLAG_RD,
146 &tcbinfo.ipi_count, 0, "Number of active PCBs");
147
148static int icmp_may_rst = 1;
149SYSCTL_INT(_net_inet_tcp, OID_AUTO, icmp_may_rst, CTLFLAG_RW, &icmp_may_rst, 0,
150 "Certain ICMP unreachable messages may abort connections in SYN_SENT");
151
152static int tcp_isn_reseed_interval = 0;
153SYSCTL_INT(_net_inet_tcp, OID_AUTO, isn_reseed_interval, CTLFLAG_RW,
154 &tcp_isn_reseed_interval, 0, "Seconds between reseeding of ISN secret");
155
156/*
157 * TCP bandwidth limiting sysctls. Note that the default lower bound of
158 * 1024 exists only for debugging. A good production default would be
159 * something like 6100.
160 */
161static int tcp_inflight_enable = 0;
162SYSCTL_INT(_net_inet_tcp, OID_AUTO, inflight_enable, CTLFLAG_RW,
163 &tcp_inflight_enable, 0, "Enable automatic TCP inflight data limiting");
164
165static int tcp_inflight_debug = 0;
166SYSCTL_INT(_net_inet_tcp, OID_AUTO, inflight_debug, CTLFLAG_RW,
167 &tcp_inflight_debug, 0, "Debug TCP inflight calculations");
168
169static int tcp_inflight_min = 6144;
170SYSCTL_INT(_net_inet_tcp, OID_AUTO, inflight_min, CTLFLAG_RW,
171 &tcp_inflight_min, 0, "Lower-bound for TCP inflight window");
172
173static int tcp_inflight_max = TCP_MAXWIN << TCP_MAX_WINSHIFT;
174SYSCTL_INT(_net_inet_tcp, OID_AUTO, inflight_max, CTLFLAG_RW,
175 &tcp_inflight_max, 0, "Upper-bound for TCP inflight window");
176static int tcp_inflight_stab = 20;
177SYSCTL_INT(_net_inet_tcp, OID_AUTO, inflight_stab, CTLFLAG_RW,
178 &tcp_inflight_stab, 0, "Inflight Algorithm Stabilization 20 = 2 packets");
179
180static void tcp_cleartaocache(void);
181static struct inpcb *tcp_notify(struct inpcb *, int);
182static void tcp_discardcb(struct tcpcb *);
183
184/*
185 * Target size of TCP PCB hash tables. Must be a power of two.
186 *
187 * Note that this can be overridden by the kernel environment
188 * variable net.inet.tcp.tcbhashsize
189 */
190#ifndef TCBHASHSIZE
191#define TCBHASHSIZE 512
192#endif
193
194/*
195 * XXX
196 * Callouts should be moved into struct tcp directly. They are currently
197 * separate becuase the tcpcb structure is exported to userland for sysctl
198 * parsing purposes, which do not know about callouts.
199 */
200struct tcpcb_mem {
201 struct tcpcb tcb;
202 struct callout tcpcb_mem_rexmt, tcpcb_mem_persist, tcpcb_mem_keep;
203 struct callout tcpcb_mem_2msl, tcpcb_mem_delack;
204};
205
206static uma_zone_t tcpcb_zone;
207static uma_zone_t tcptw_zone;
208
209/*
210 * Tcp initialization
211 */
212void
213tcp_init()
214{
215 int hashsize = TCBHASHSIZE;
216
217 tcp_ccgen = 1;
218 tcp_cleartaocache();
219
220 tcp_delacktime = TCPTV_DELACK;
221 tcp_keepinit = TCPTV_KEEP_INIT;
222 tcp_keepidle = TCPTV_KEEP_IDLE;
223 tcp_keepintvl = TCPTV_KEEPINTVL;
224 tcp_maxpersistidle = TCPTV_KEEP_IDLE;
225 tcp_msl = TCPTV_MSL;
226 tcp_rexmit_min = TCPTV_MIN;
227 tcp_rexmit_slop = TCPTV_CPU_VAR;
228
229 INP_INFO_LOCK_INIT(&tcbinfo, "tcp");
230 LIST_INIT(&tcb);
231 tcbinfo.listhead = &tcb;
232 TUNABLE_INT_FETCH("net.inet.tcp.tcbhashsize", &hashsize);
233 if (!powerof2(hashsize)) {
234 printf("WARNING: TCB hash size not a power of 2\n");
235 hashsize = 512; /* safe default */
236 }
237 tcp_tcbhashsize = hashsize;
238 tcbinfo.hashbase = hashinit(hashsize, M_PCB, &tcbinfo.hashmask);
239 tcbinfo.porthashbase = hashinit(hashsize, M_PCB,
240 &tcbinfo.porthashmask);
241 tcbinfo.ipi_zone = uma_zcreate("inpcb", sizeof(struct inpcb),
242 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE);
243 uma_zone_set_max(tcbinfo.ipi_zone, maxsockets);
244#ifdef INET6
245#define TCP_MINPROTOHDR (sizeof(struct ip6_hdr) + sizeof(struct tcphdr))
246#else /* INET6 */
247#define TCP_MINPROTOHDR (sizeof(struct tcpiphdr))
248#endif /* INET6 */
249 if (max_protohdr < TCP_MINPROTOHDR)
250 max_protohdr = TCP_MINPROTOHDR;
251 if (max_linkhdr + TCP_MINPROTOHDR > MHLEN)
252 panic("tcp_init");
253#undef TCP_MINPROTOHDR
254 /*
255 * These have to be type stable for the benefit of the timers.
256 */
257 tcpcb_zone = uma_zcreate("tcpcb", sizeof(struct tcpcb_mem),
258 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE);
259 uma_zone_set_max(tcpcb_zone, maxsockets);
260 tcptw_zone = uma_zcreate("tcptw", sizeof(struct tcptw),
261 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE);
262 uma_zone_set_max(tcptw_zone, maxsockets);
263 tcp_timer_init();
264 syncache_init();
265}
266
267/*
268 * Fill in the IP and TCP headers for an outgoing packet, given the tcpcb.
269 * tcp_template used to store this data in mbufs, but we now recopy it out
270 * of the tcpcb each time to conserve mbufs.
271 */
272void
273tcpip_fillheaders(inp, ip_ptr, tcp_ptr)
274 struct inpcb *inp;
275 void *ip_ptr;
276 void *tcp_ptr;
277{
278 struct tcphdr *th = (struct tcphdr *)tcp_ptr;
279
280#ifdef INET6
281 if ((inp->inp_vflag & INP_IPV6) != 0) {
282 struct ip6_hdr *ip6;
283
284 ip6 = (struct ip6_hdr *)ip_ptr;
285 ip6->ip6_flow = (ip6->ip6_flow & ~IPV6_FLOWINFO_MASK) |
286 (inp->in6p_flowinfo & IPV6_FLOWINFO_MASK);
287 ip6->ip6_vfc = (ip6->ip6_vfc & ~IPV6_VERSION_MASK) |
288 (IPV6_VERSION & IPV6_VERSION_MASK);
289 ip6->ip6_nxt = IPPROTO_TCP;
290 ip6->ip6_plen = sizeof(struct tcphdr);
291 ip6->ip6_src = inp->in6p_laddr;
292 ip6->ip6_dst = inp->in6p_faddr;
293 } else
294#endif
295 {
296 struct ip *ip;
297
298 ip = (struct ip *)ip_ptr;
299 ip->ip_v = IPVERSION;
300 ip->ip_hl = 5;
301 ip->ip_tos = inp->inp_ip_tos;
302 ip->ip_len = 0;
303 ip->ip_id = 0;
304 ip->ip_off = 0;
305 ip->ip_ttl = inp->inp_ip_ttl;
306 ip->ip_sum = 0;
307 ip->ip_p = IPPROTO_TCP;
308 ip->ip_src = inp->inp_laddr;
309 ip->ip_dst = inp->inp_faddr;
310 }
311 th->th_sport = inp->inp_lport;
312 th->th_dport = inp->inp_fport;
313 th->th_seq = 0;
314 th->th_ack = 0;
315 th->th_x2 = 0;
316 th->th_off = 5;
317 th->th_flags = 0;
318 th->th_win = 0;
319 th->th_urp = 0;
320 th->th_sum = 0; /* in_pseudo() is called later for ipv4 */
321}
322
323/*
324 * Create template to be used to send tcp packets on a connection.
325 * Allocates an mbuf and fills in a skeletal tcp/ip header. The only
326 * use for this function is in keepalives, which use tcp_respond.
327 */
328struct tcptemp *
329tcpip_maketemplate(inp)
330 struct inpcb *inp;
331{
332 struct mbuf *m;
333 struct tcptemp *n;
334
335 m = m_get(M_DONTWAIT, MT_HEADER);
336 if (m == NULL)
337 return (0);
338 m->m_len = sizeof(struct tcptemp);
339 n = mtod(m, struct tcptemp *);
340
341 tcpip_fillheaders(inp, (void *)&n->tt_ipgen, (void *)&n->tt_t);
342 return (n);
343}
344
345/*
346 * Send a single message to the TCP at address specified by
347 * the given TCP/IP header. If m == 0, then we make a copy
348 * of the tcpiphdr at ti and send directly to the addressed host.
349 * This is used to force keep alive messages out using the TCP
350 * template for a connection. If flags are given then we send
351 * a message back to the TCP which originated the * segment ti,
352 * and discard the mbuf containing it and any other attached mbufs.
353 *
354 * In any case the ack and sequence number of the transmitted
355 * segment are as specified by the parameters.
356 *
357 * NOTE: If m != NULL, then ti must point to *inside* the mbuf.
358 */
359void
360tcp_respond(tp, ipgen, th, m, ack, seq, flags)
361 struct tcpcb *tp;
362 void *ipgen;
363 register struct tcphdr *th;
364 register struct mbuf *m;
365 tcp_seq ack, seq;
366 int flags;
367{
368 register int tlen;
369 int win = 0;
370 struct route *ro = 0;
371 struct route sro;
372 struct ip *ip;
373 struct tcphdr *nth;
374#ifdef INET6
375 struct route_in6 *ro6 = 0;
376 struct route_in6 sro6;
377 struct ip6_hdr *ip6;
378 int isipv6;
379#endif /* INET6 */
380 int ipflags = 0;
381
382 KASSERT(tp != NULL || m != NULL, ("tcp_respond: tp and m both NULL"));
383
384#ifdef INET6
385 isipv6 = ((struct ip *)ipgen)->ip_v == 6;
386 ip6 = ipgen;
387#endif /* INET6 */
388 ip = ipgen;
389
390 if (tp) {
391 if (!(flags & TH_RST)) {
392 win = sbspace(&tp->t_inpcb->inp_socket->so_rcv);
393 if (win > (long)TCP_MAXWIN << tp->rcv_scale)
394 win = (long)TCP_MAXWIN << tp->rcv_scale;
395 }
396#ifdef INET6
397 if (isipv6)
398 ro6 = &tp->t_inpcb->in6p_route;
399 else
400#endif /* INET6 */
401 ro = &tp->t_inpcb->inp_route;
402 } else {
403#ifdef INET6
404 if (isipv6) {
405 ro6 = &sro6;
406 bzero(ro6, sizeof *ro6);
407 } else
408#endif /* INET6 */
409 {
410 ro = &sro;
411 bzero(ro, sizeof *ro);
412 }
413 }
414 if (m == 0) {
415 m = m_gethdr(M_DONTWAIT, MT_HEADER);
416 if (m == NULL)
417 return;
418 tlen = 0;
419 m->m_data += max_linkhdr;
420#ifdef INET6
421 if (isipv6) {
422 bcopy((caddr_t)ip6, mtod(m, caddr_t),
423 sizeof(struct ip6_hdr));
424 ip6 = mtod(m, struct ip6_hdr *);
425 nth = (struct tcphdr *)(ip6 + 1);
426 } else
427#endif /* INET6 */
428 {
429 bcopy((caddr_t)ip, mtod(m, caddr_t), sizeof(struct ip));
430 ip = mtod(m, struct ip *);
431 nth = (struct tcphdr *)(ip + 1);
432 }
433 bcopy((caddr_t)th, (caddr_t)nth, sizeof(struct tcphdr));
434 flags = TH_ACK;
435 } else {
436 m_freem(m->m_next);
437 m->m_next = 0;
438 m->m_data = (caddr_t)ipgen;
439 /* m_len is set later */
440 tlen = 0;
441#define xchg(a,b,type) { type t; t=a; a=b; b=t; }
442#ifdef INET6
443 if (isipv6) {
444 xchg(ip6->ip6_dst, ip6->ip6_src, struct in6_addr);
445 nth = (struct tcphdr *)(ip6 + 1);
446 } else
447#endif /* INET6 */
448 {
449 xchg(ip->ip_dst.s_addr, ip->ip_src.s_addr, n_long);
450 nth = (struct tcphdr *)(ip + 1);
451 }
452 if (th != nth) {
453 /*
454 * this is usually a case when an extension header
455 * exists between the IPv6 header and the
456 * TCP header.
457 */
458 nth->th_sport = th->th_sport;
459 nth->th_dport = th->th_dport;
460 }
461 xchg(nth->th_dport, nth->th_sport, n_short);
462#undef xchg
463 }
464#ifdef INET6
465 if (isipv6) {
466 ip6->ip6_flow = 0;
467 ip6->ip6_vfc = IPV6_VERSION;
468 ip6->ip6_nxt = IPPROTO_TCP;
469 ip6->ip6_plen = htons((u_short)(sizeof (struct tcphdr) +
470 tlen));
471 tlen += sizeof (struct ip6_hdr) + sizeof (struct tcphdr);
472 } else
473#endif
474 {
475 tlen += sizeof (struct tcpiphdr);
476 ip->ip_len = tlen;
477 ip->ip_ttl = ip_defttl;
478 }
479 m->m_len = tlen;
480 m->m_pkthdr.len = tlen;
481 m->m_pkthdr.rcvif = (struct ifnet *) 0;
482#ifdef MAC
483 if (tp != NULL && tp->t_inpcb != NULL) {
484 /*
485 * Packet is associated with a socket, so allow the
486 * label of the response to reflect the socket label.
487 */
488 mac_create_mbuf_from_socket(tp->t_inpcb->inp_socket, m);
489 } else {
490 /*
491 * XXXMAC: This will need to call a mac function that
492 * modifies the mbuf label in place for TCP datagrams
493 * not associated with a PCB.
494 */
495 }
496#endif
497 nth->th_seq = htonl(seq);
498 nth->th_ack = htonl(ack);
499 nth->th_x2 = 0;
500 nth->th_off = sizeof (struct tcphdr) >> 2;
501 nth->th_flags = flags;
502 if (tp)
503 nth->th_win = htons((u_short) (win >> tp->rcv_scale));
504 else
505 nth->th_win = htons((u_short)win);
506 nth->th_urp = 0;
507#ifdef INET6
508 if (isipv6) {
509 nth->th_sum = 0;
510 nth->th_sum = in6_cksum(m, IPPROTO_TCP,
511 sizeof(struct ip6_hdr),
512 tlen - sizeof(struct ip6_hdr));
513 ip6->ip6_hlim = in6_selecthlim(tp ? tp->t_inpcb : NULL,
514 ro6 && ro6->ro_rt ?
515 ro6->ro_rt->rt_ifp :
516 NULL);
517 } else
518#endif /* INET6 */
519 {
520 nth->th_sum = in_pseudo(ip->ip_src.s_addr, ip->ip_dst.s_addr,
521 htons((u_short)(tlen - sizeof(struct ip) + ip->ip_p)));
522 m->m_pkthdr.csum_flags = CSUM_TCP;
523 m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum);
524 }
525#ifdef TCPDEBUG
526 if (tp == NULL || (tp->t_inpcb->inp_socket->so_options & SO_DEBUG))
527 tcp_trace(TA_OUTPUT, 0, tp, mtod(m, void *), th, 0);
528#endif
529#ifdef INET6
530 if (isipv6) {
531 (void)ip6_output(m, NULL, ro6, ipflags, NULL, NULL,
532 tp ? tp->t_inpcb : NULL);
533 if (ro6 == &sro6 && ro6->ro_rt) {
534 RTFREE(ro6->ro_rt);
535 ro6->ro_rt = NULL;
536 }
537 } else
538#endif /* INET6 */
539 {
540 (void) ip_output(m, NULL, ro, ipflags, NULL, tp ? tp->t_inpcb : NULL);
541 if (ro == &sro && ro->ro_rt) {
542 RTFREE(ro->ro_rt);
543 ro->ro_rt = NULL;
544 }
545 }
546}
547
548/*
549 * Create a new TCP control block, making an
550 * empty reassembly queue and hooking it to the argument
551 * protocol control block. The `inp' parameter must have
552 * come from the zone allocator set up in tcp_init().
553 */
554struct tcpcb *
555tcp_newtcpcb(inp)
556 struct inpcb *inp;
557{
558 struct tcpcb_mem *tm;
559 struct tcpcb *tp;
560#ifdef INET6
561 int isipv6 = (inp->inp_vflag & INP_IPV6) != 0;
562#endif /* INET6 */
563
564 tm = uma_zalloc(tcpcb_zone, M_NOWAIT | M_ZERO);
565 if (tm == NULL)
566 return (NULL);
567 tp = &tm->tcb;
568 /* LIST_INIT(&tp->t_segq); */ /* XXX covered by M_ZERO */
569 tp->t_maxseg = tp->t_maxopd =
570#ifdef INET6
571 isipv6 ? tcp_v6mssdflt :
572#endif /* INET6 */
573 tcp_mssdflt;
574
575 /* Set up our timeouts. */
576 callout_init(tp->tt_rexmt = &tm->tcpcb_mem_rexmt, 0);
577 callout_init(tp->tt_persist = &tm->tcpcb_mem_persist, 0);
578 callout_init(tp->tt_keep = &tm->tcpcb_mem_keep, 0);
579 callout_init(tp->tt_2msl = &tm->tcpcb_mem_2msl, 0);
580 callout_init(tp->tt_delack = &tm->tcpcb_mem_delack, 0);
581
582 if (tcp_do_rfc1323)
583 tp->t_flags = (TF_REQ_SCALE|TF_REQ_TSTMP);
584 if (tcp_do_rfc1644)
585 tp->t_flags |= TF_REQ_CC;
586 tp->t_inpcb = inp; /* XXX */
587 /*
588 * Init srtt to TCPTV_SRTTBASE (0), so we can tell that we have no
589 * rtt estimate. Set rttvar so that srtt + 4 * rttvar gives
590 * reasonable initial retransmit time.
591 */
592 tp->t_srtt = TCPTV_SRTTBASE;
593 tp->t_rttvar = ((TCPTV_RTOBASE - TCPTV_SRTTBASE) << TCP_RTTVAR_SHIFT) / 4;
594 tp->t_rttmin = tcp_rexmit_min;
595 tp->t_rxtcur = TCPTV_RTOBASE;
596 tp->snd_cwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT;
597 tp->snd_bwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT;
598 tp->snd_ssthresh = TCP_MAXWIN << TCP_MAX_WINSHIFT;
599 tp->t_rcvtime = ticks;
600 tp->t_bw_rtttime = ticks;
601 /*
602 * IPv4 TTL initialization is necessary for an IPv6 socket as well,
603 * because the socket may be bound to an IPv6 wildcard address,
604 * which may match an IPv4-mapped IPv6 address.
605 */
606 inp->inp_ip_ttl = ip_defttl;
607 inp->inp_ppcb = (caddr_t)tp;
608 return (tp); /* XXX */
609}
610
611/*
612 * Drop a TCP connection, reporting
613 * the specified error. If connection is synchronized,
614 * then send a RST to peer.
615 */
616struct tcpcb *
617tcp_drop(tp, errno)
618 register struct tcpcb *tp;
619 int errno;
620{
621 struct socket *so = tp->t_inpcb->inp_socket;
622
623 if (TCPS_HAVERCVDSYN(tp->t_state)) {
624 tp->t_state = TCPS_CLOSED;
625 (void) tcp_output(tp);
626 tcpstat.tcps_drops++;
627 } else
628 tcpstat.tcps_conndrops++;
629 if (errno == ETIMEDOUT && tp->t_softerror)
630 errno = tp->t_softerror;
631 so->so_error = errno;
632 return (tcp_close(tp));
633}
634
635static void
636tcp_discardcb(tp)
637 struct tcpcb *tp;
638{
639 struct tseg_qent *q;
640 struct inpcb *inp = tp->t_inpcb;
641 struct socket *so = inp->inp_socket;
642#ifdef INET6
643 int isipv6 = (inp->inp_vflag & INP_IPV6) != 0;
644#endif /* INET6 */
645 struct rtentry *rt;
646 int dosavessthresh;
647
648 /*
649 * Make sure that all of our timers are stopped before we
650 * delete the PCB.
651 */
652 callout_stop(tp->tt_rexmt);
653 callout_stop(tp->tt_persist);
654 callout_stop(tp->tt_keep);
655 callout_stop(tp->tt_2msl);
656 callout_stop(tp->tt_delack);
657
658 /*
659 * If we got enough samples through the srtt filter,
660 * save the rtt and rttvar in the routing entry.
661 * 'Enough' is arbitrarily defined as the 16 samples.
662 * 16 samples is enough for the srtt filter to converge
663 * to within 5% of the correct value; fewer samples and
664 * we could save a very bogus rtt.
665 *
666 * Don't update the default route's characteristics and don't
667 * update anything that the user "locked".
668 */
669 if (tp->t_rttupdated >= 16) {
670 register u_long i = 0;
671#ifdef INET6
672 if (isipv6) {
673 struct sockaddr_in6 *sin6;
674
675 if ((rt = inp->in6p_route.ro_rt) == NULL)
676 goto no_valid_rt;
677 sin6 = (struct sockaddr_in6 *)rt_key(rt);
678 if (IN6_IS_ADDR_UNSPECIFIED(&sin6->sin6_addr))
679 goto no_valid_rt;
680 }
681 else
682#endif /* INET6 */
683 if ((rt = inp->inp_route.ro_rt) == NULL ||
684 ((struct sockaddr_in *)rt_key(rt))->sin_addr.s_addr
685 == INADDR_ANY)
686 goto no_valid_rt;
687
688 if ((rt->rt_rmx.rmx_locks & RTV_RTT) == 0) {
689 i = tp->t_srtt *
690 (RTM_RTTUNIT / (hz * TCP_RTT_SCALE));
691 if (rt->rt_rmx.rmx_rtt && i)
692 /*
693 * filter this update to half the old & half
694 * the new values, converting scale.
695 * See route.h and tcp_var.h for a
696 * description of the scaling constants.
697 */
698 rt->rt_rmx.rmx_rtt =
699 (rt->rt_rmx.rmx_rtt + i) / 2;
700 else
701 rt->rt_rmx.rmx_rtt = i;
702 tcpstat.tcps_cachedrtt++;
703 }
704 if ((rt->rt_rmx.rmx_locks & RTV_RTTVAR) == 0) {
705 i = tp->t_rttvar *
706 (RTM_RTTUNIT / (hz * TCP_RTTVAR_SCALE));
707 if (rt->rt_rmx.rmx_rttvar && i)
708 rt->rt_rmx.rmx_rttvar =
709 (rt->rt_rmx.rmx_rttvar + i) / 2;
710 else
711 rt->rt_rmx.rmx_rttvar = i;
712 tcpstat.tcps_cachedrttvar++;
713 }
714 /*
715 * The old comment here said:
716 * update the pipelimit (ssthresh) if it has been updated
717 * already or if a pipesize was specified & the threshhold
718 * got below half the pipesize. I.e., wait for bad news
719 * before we start updating, then update on both good
720 * and bad news.
721 *
722 * But we want to save the ssthresh even if no pipesize is
723 * specified explicitly in the route, because such
724 * connections still have an implicit pipesize specified
725 * by the global tcp_sendspace. In the absence of a reliable
726 * way to calculate the pipesize, it will have to do.
727 */
728 i = tp->snd_ssthresh;
729 if (rt->rt_rmx.rmx_sendpipe != 0)
730 dosavessthresh = (i < rt->rt_rmx.rmx_sendpipe / 2);
731 else
732 dosavessthresh = (i < so->so_snd.sb_hiwat / 2);
733 if (((rt->rt_rmx.rmx_locks & RTV_SSTHRESH) == 0 &&
734 i != 0 && rt->rt_rmx.rmx_ssthresh != 0)
735 || dosavessthresh) {
736 /*
737 * convert the limit from user data bytes to
738 * packets then to packet data bytes.
739 */
740 i = (i + tp->t_maxseg / 2) / tp->t_maxseg;
741 if (i < 2)
742 i = 2;
743 i *= (u_long)(tp->t_maxseg +
744#ifdef INET6
745 (isipv6 ? sizeof (struct ip6_hdr) +
746 sizeof (struct tcphdr) :
747#endif
748 sizeof (struct tcpiphdr)
749#ifdef INET6
750 )
751#endif
752 );
753 if (rt->rt_rmx.rmx_ssthresh)
754 rt->rt_rmx.rmx_ssthresh =
755 (rt->rt_rmx.rmx_ssthresh + i) / 2;
756 else
757 rt->rt_rmx.rmx_ssthresh = i;
758 tcpstat.tcps_cachedssthresh++;
759 }
760 }
761 no_valid_rt:
762 /* free the reassembly queue, if any */
763 while ((q = LIST_FIRST(&tp->t_segq)) != NULL) {
764 LIST_REMOVE(q, tqe_q);
765 m_freem(q->tqe_m);
766 FREE(q, M_TSEGQ);
767 }
768 inp->inp_ppcb = NULL;
769 tp->t_inpcb = NULL;
770 uma_zfree(tcpcb_zone, tp);
771 soisdisconnected(so);
772}
773
774/*
775 * Close a TCP control block:
776 * discard all space held by the tcp
777 * discard internet protocol block
778 * wake up any sleepers
779 */
780struct tcpcb *
781tcp_close(tp)
782 struct tcpcb *tp;
783{
784 struct inpcb *inp = tp->t_inpcb;
785#ifdef INET6
786 struct socket *so = inp->inp_socket;
787#endif
788
789 tcp_discardcb(tp);
790#ifdef INET6
791 if (INP_CHECK_SOCKAF(so, AF_INET6))
792 in6_pcbdetach(inp);
793 else
794#endif
795 in_pcbdetach(inp);
796 tcpstat.tcps_closed++;
797 return ((struct tcpcb *)0);
798}
799
800void
801tcp_drain()
802{
803 if (do_tcpdrain)
804 {
805 struct inpcb *inpb;
806 struct tcpcb *tcpb;
807 struct tseg_qent *te;
808
809 /*
810 * Walk the tcpbs, if existing, and flush the reassembly queue,
811 * if there is one...
812 * XXX: The "Net/3" implementation doesn't imply that the TCP
813 * reassembly queue should be flushed, but in a situation
814 * where we're really low on mbufs, this is potentially
815 * usefull.
816 */
817 INP_INFO_RLOCK(&tcbinfo);
818 LIST_FOREACH(inpb, tcbinfo.listhead, inp_list) {
819 if (inpb->inp_vflag & INP_TIMEWAIT)
820 continue;
821 INP_LOCK(inpb);
822 if ((tcpb = intotcpcb(inpb))) {
823 while ((te = LIST_FIRST(&tcpb->t_segq))
824 != NULL) {
825 LIST_REMOVE(te, tqe_q);
826 m_freem(te->tqe_m);
827 FREE(te, M_TSEGQ);
828 }
829 }
830 INP_UNLOCK(inpb);
831 }
832 INP_INFO_RUNLOCK(&tcbinfo);
833 }
834}
835
836/*
837 * Notify a tcp user of an asynchronous error;
838 * store error as soft error, but wake up user
839 * (for now, won't do anything until can select for soft error).
840 *
841 * Do not wake up user since there currently is no mechanism for
842 * reporting soft errors (yet - a kqueue filter may be added).
843 */
844static struct inpcb *
845tcp_notify(inp, error)
846 struct inpcb *inp;
847 int error;
848{
849 struct tcpcb *tp = (struct tcpcb *)inp->inp_ppcb;
850
851 /*
852 * Ignore some errors if we are hooked up.
853 * If connection hasn't completed, has retransmitted several times,
854 * and receives a second error, give up now. This is better
855 * than waiting a long time to establish a connection that
856 * can never complete.
857 */
858 if (tp->t_state == TCPS_ESTABLISHED &&
859 (error == EHOSTUNREACH || error == ENETUNREACH ||
860 error == EHOSTDOWN)) {
861 return inp;
862 } else if (tp->t_state < TCPS_ESTABLISHED && tp->t_rxtshift > 3 &&
863 tp->t_softerror) {
864 tcp_drop(tp, error);
865 return (struct inpcb *)0;
866 } else {
867 tp->t_softerror = error;
868 return inp;
869 }
870#if 0
871 wakeup( &so->so_timeo);
872 sorwakeup(so);
873 sowwakeup(so);
874#endif
875}
876
877static int
878tcp_pcblist(SYSCTL_HANDLER_ARGS)
879{
880 int error, i, n, s;
881 struct inpcb *inp, **inp_list;
882 inp_gen_t gencnt;
883 struct xinpgen xig;
884
885 /*
886 * The process of preparing the TCB list is too time-consuming and
887 * resource-intensive to repeat twice on every request.
888 */
889 if (req->oldptr == 0) {
890 n = tcbinfo.ipi_count;
891 req->oldidx = 2 * (sizeof xig)
892 + (n + n/8) * sizeof(struct xtcpcb);
893 return 0;
894 }
895
896 if (req->newptr != 0)
897 return EPERM;
898
899 /*
900 * OK, now we're committed to doing something.
901 */
902 s = splnet();
903 INP_INFO_RLOCK(&tcbinfo);
904 gencnt = tcbinfo.ipi_gencnt;
905 n = tcbinfo.ipi_count;
906 INP_INFO_RUNLOCK(&tcbinfo);
907 splx(s);
908
909 sysctl_wire_old_buffer(req, 2 * (sizeof xig)
910 + n * sizeof(struct xtcpcb));
911
912 xig.xig_len = sizeof xig;
913 xig.xig_count = n;
914 xig.xig_gen = gencnt;
915 xig.xig_sogen = so_gencnt;
916 error = SYSCTL_OUT(req, &xig, sizeof xig);
917 if (error)
918 return error;
919
920 inp_list = malloc(n * sizeof *inp_list, M_TEMP, M_WAITOK);
921 if (inp_list == 0)
922 return ENOMEM;
923
924 s = splnet();
925 INP_INFO_RLOCK(&tcbinfo);
926 for (inp = LIST_FIRST(tcbinfo.listhead), i = 0; inp && i < n;
927 inp = LIST_NEXT(inp, inp_list)) {
928 INP_LOCK(inp);
|
929 if (inp->inp_gencnt <= gencnt &&
930 (((inp->inp_vflag & INP_TIMEWAIT) &&
931 cr_cansee(req->td->td_ucred, intotw(inp)->tw_cred) == 0) ||
932 cr_canseesocket(req->td->td_ucred, inp->inp_socket) == 0))
933 inp_list[i++] = inp;
| 929 if (inp->inp_gencnt <= gencnt) {
930 /*
931 * XXX: This use of cr_cansee(), introduced with
932 * TCP state changes, is not quite right, but for
933 * now, better than nothing.
934 */
935 if (inp->inp_vflag & INP_TIMEWAIT)
936 error = cr_cansee(req->td->td_ucred,
937 intotw(inp)->tw_cred);
938 else
939 error = cr_canseesocket(req->td->td_ucred,
940 inp->inp_socket);
941 if (error == 0)
942 inp_list[i++] = inp;
943 }
|
934 INP_UNLOCK(inp);
935 }
936 INP_INFO_RUNLOCK(&tcbinfo);
937 splx(s);
938 n = i;
939
940 error = 0;
941 for (i = 0; i < n; i++) {
942 inp = inp_list[i];
943 if (inp->inp_gencnt <= gencnt) {
944 struct xtcpcb xt;
945 caddr_t inp_ppcb;
946 xt.xt_len = sizeof xt;
947 /* XXX should avoid extra copy */
948 bcopy(inp, &xt.xt_inp, sizeof *inp);
949 inp_ppcb = inp->inp_ppcb;
950 if (inp_ppcb == NULL)
951 bzero((char *) &xt.xt_tp, sizeof xt.xt_tp);
952 else if (inp->inp_vflag & INP_TIMEWAIT) {
953 bzero((char *) &xt.xt_tp, sizeof xt.xt_tp);
954 xt.xt_tp.t_state = TCPS_TIME_WAIT;
955 } else
956 bcopy(inp_ppcb, &xt.xt_tp, sizeof xt.xt_tp);
957 if (inp->inp_socket)
958 sotoxsocket(inp->inp_socket, &xt.xt_socket);
959 else {
960 bzero(&xt.xt_socket, sizeof xt.xt_socket);
961 xt.xt_socket.xso_protocol = IPPROTO_TCP;
962 }
963 xt.xt_inp.inp_gencnt = inp->inp_gencnt;
964 error = SYSCTL_OUT(req, &xt, sizeof xt);
965 }
966 }
967 if (!error) {
968 /*
969 * Give the user an updated idea of our state.
970 * If the generation differs from what we told
971 * her before, she knows that something happened
972 * while we were processing this request, and it
973 * might be necessary to retry.
974 */
975 s = splnet();
976 INP_INFO_RLOCK(&tcbinfo);
977 xig.xig_gen = tcbinfo.ipi_gencnt;
978 xig.xig_sogen = so_gencnt;
979 xig.xig_count = tcbinfo.ipi_count;
980 INP_INFO_RUNLOCK(&tcbinfo);
981 splx(s);
982 error = SYSCTL_OUT(req, &xig, sizeof xig);
983 }
984 free(inp_list, M_TEMP);
985 return error;
986}
987
988SYSCTL_PROC(_net_inet_tcp, TCPCTL_PCBLIST, pcblist, CTLFLAG_RD, 0, 0,
989 tcp_pcblist, "S,xtcpcb", "List of active TCP connections");
990
991static int
992tcp_getcred(SYSCTL_HANDLER_ARGS)
993{
994 struct xucred xuc;
995 struct sockaddr_in addrs[2];
996 struct inpcb *inp;
997 int error, s;
998
999 error = suser_cred(req->td->td_ucred, PRISON_ROOT);
1000 if (error)
1001 return (error);
1002 error = SYSCTL_IN(req, addrs, sizeof(addrs));
1003 if (error)
1004 return (error);
1005 s = splnet();
1006 INP_INFO_RLOCK(&tcbinfo);
1007 inp = in_pcblookup_hash(&tcbinfo, addrs[1].sin_addr, addrs[1].sin_port,
1008 addrs[0].sin_addr, addrs[0].sin_port, 0, NULL);
1009 if (inp == NULL) {
1010 error = ENOENT;
1011 goto outunlocked;
1012 }
1013 INP_LOCK(inp);
1014 if (inp->inp_socket == NULL) {
1015 error = ENOENT;
1016 goto out;
1017 }
1018 error = cr_canseesocket(req->td->td_ucred, inp->inp_socket);
1019 if (error)
1020 goto out;
1021 cru2x(inp->inp_socket->so_cred, &xuc);
1022out:
1023 INP_UNLOCK(inp);
1024outunlocked:
1025 INP_INFO_RUNLOCK(&tcbinfo);
1026 splx(s);
1027 if (error == 0)
1028 error = SYSCTL_OUT(req, &xuc, sizeof(struct xucred));
1029 return (error);
1030}
1031
1032SYSCTL_PROC(_net_inet_tcp, OID_AUTO, getcred,
1033 CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_PRISON, 0, 0,
1034 tcp_getcred, "S,xucred", "Get the xucred of a TCP connection");
1035
1036#ifdef INET6
1037static int
1038tcp6_getcred(SYSCTL_HANDLER_ARGS)
1039{
1040 struct xucred xuc;
1041 struct sockaddr_in6 addrs[2];
1042 struct inpcb *inp;
1043 int error, s, mapped = 0;
1044
1045 error = suser_cred(req->td->td_ucred, PRISON_ROOT);
1046 if (error)
1047 return (error);
1048 error = SYSCTL_IN(req, addrs, sizeof(addrs));
1049 if (error)
1050 return (error);
1051 if (IN6_IS_ADDR_V4MAPPED(&addrs[0].sin6_addr)) {
1052 if (IN6_IS_ADDR_V4MAPPED(&addrs[1].sin6_addr))
1053 mapped = 1;
1054 else
1055 return (EINVAL);
1056 }
1057 s = splnet();
1058 INP_INFO_RLOCK(&tcbinfo);
1059 if (mapped == 1)
1060 inp = in_pcblookup_hash(&tcbinfo,
1061 *(struct in_addr *)&addrs[1].sin6_addr.s6_addr[12],
1062 addrs[1].sin6_port,
1063 *(struct in_addr *)&addrs[0].sin6_addr.s6_addr[12],
1064 addrs[0].sin6_port,
1065 0, NULL);
1066 else
1067 inp = in6_pcblookup_hash(&tcbinfo, &addrs[1].sin6_addr,
1068 addrs[1].sin6_port,
1069 &addrs[0].sin6_addr, addrs[0].sin6_port,
1070 0, NULL);
1071 if (inp == NULL) {
1072 error = ENOENT;
1073 goto outunlocked;
1074 }
1075 INP_LOCK(inp);
1076 if (inp->inp_socket == NULL) {
1077 error = ENOENT;
1078 goto out;
1079 }
1080 error = cr_canseesocket(req->td->td_ucred, inp->inp_socket);
1081 if (error)
1082 goto out;
1083 cru2x(inp->inp_socket->so_cred, &xuc);
1084out:
1085 INP_UNLOCK(inp);
1086outunlocked:
1087 INP_INFO_RUNLOCK(&tcbinfo);
1088 splx(s);
1089 if (error == 0)
1090 error = SYSCTL_OUT(req, &xuc, sizeof(struct xucred));
1091 return (error);
1092}
1093
1094SYSCTL_PROC(_net_inet6_tcp6, OID_AUTO, getcred,
1095 CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_PRISON, 0, 0,
1096 tcp6_getcred, "S,xucred", "Get the xucred of a TCP6 connection");
1097#endif
1098
1099
1100void
1101tcp_ctlinput(cmd, sa, vip)
1102 int cmd;
1103 struct sockaddr *sa;
1104 void *vip;
1105{
1106 struct ip *ip = vip;
1107 struct tcphdr *th;
1108 struct in_addr faddr;
1109 struct inpcb *inp;
1110 struct tcpcb *tp;
1111 struct inpcb *(*notify)(struct inpcb *, int) = tcp_notify;
1112 tcp_seq icmp_seq;
1113 int s;
1114
1115 faddr = ((struct sockaddr_in *)sa)->sin_addr;
1116 if (sa->sa_family != AF_INET || faddr.s_addr == INADDR_ANY)
1117 return;
1118
1119 if (cmd == PRC_QUENCH)
1120 notify = tcp_quench;
1121 else if (icmp_may_rst && (cmd == PRC_UNREACH_ADMIN_PROHIB ||
1122 cmd == PRC_UNREACH_PORT || cmd == PRC_TIMXCEED_INTRANS) && ip)
1123 notify = tcp_drop_syn_sent;
1124 else if (cmd == PRC_MSGSIZE)
1125 notify = tcp_mtudisc;
1126 else if (PRC_IS_REDIRECT(cmd)) {
1127 ip = 0;
1128 notify = in_rtchange;
1129 } else if (cmd == PRC_HOSTDEAD)
1130 ip = 0;
1131 else if ((unsigned)cmd > PRC_NCMDS || inetctlerrmap[cmd] == 0)
1132 return;
1133 if (ip) {
1134 s = splnet();
1135 th = (struct tcphdr *)((caddr_t)ip
1136 + (ip->ip_hl << 2));
1137 INP_INFO_WLOCK(&tcbinfo);
1138 inp = in_pcblookup_hash(&tcbinfo, faddr, th->th_dport,
1139 ip->ip_src, th->th_sport, 0, NULL);
1140 if (inp != NULL) {
1141 INP_LOCK(inp);
1142 if (inp->inp_socket != NULL) {
1143 icmp_seq = htonl(th->th_seq);
1144 tp = intotcpcb(inp);
1145 if (SEQ_GEQ(icmp_seq, tp->snd_una) &&
1146 SEQ_LT(icmp_seq, tp->snd_max))
1147 inp = (*notify)(inp, inetctlerrmap[cmd]);
1148 }
1149 if (inp)
1150 INP_UNLOCK(inp);
1151 } else {
1152 struct in_conninfo inc;
1153
1154 inc.inc_fport = th->th_dport;
1155 inc.inc_lport = th->th_sport;
1156 inc.inc_faddr = faddr;
1157 inc.inc_laddr = ip->ip_src;
1158#ifdef INET6
1159 inc.inc_isipv6 = 0;
1160#endif
1161 syncache_unreach(&inc, th);
1162 }
1163 INP_INFO_WUNLOCK(&tcbinfo);
1164 splx(s);
1165 } else
1166 in_pcbnotifyall(&tcbinfo, faddr, inetctlerrmap[cmd], notify);
1167}
1168
1169#ifdef INET6
1170void
1171tcp6_ctlinput(cmd, sa, d)
1172 int cmd;
1173 struct sockaddr *sa;
1174 void *d;
1175{
1176 struct tcphdr th;
1177 struct inpcb *(*notify)(struct inpcb *, int) = tcp_notify;
1178 struct ip6_hdr *ip6;
1179 struct mbuf *m;
1180 struct ip6ctlparam *ip6cp = NULL;
1181 const struct sockaddr_in6 *sa6_src = NULL;
1182 int off;
1183 struct tcp_portonly {
1184 u_int16_t th_sport;
1185 u_int16_t th_dport;
1186 } *thp;
1187
1188 if (sa->sa_family != AF_INET6 ||
1189 sa->sa_len != sizeof(struct sockaddr_in6))
1190 return;
1191
1192 if (cmd == PRC_QUENCH)
1193 notify = tcp_quench;
1194 else if (cmd == PRC_MSGSIZE)
1195 notify = tcp_mtudisc;
1196 else if (!PRC_IS_REDIRECT(cmd) &&
1197 ((unsigned)cmd > PRC_NCMDS || inet6ctlerrmap[cmd] == 0))
1198 return;
1199
1200 /* if the parameter is from icmp6, decode it. */
1201 if (d != NULL) {
1202 ip6cp = (struct ip6ctlparam *)d;
1203 m = ip6cp->ip6c_m;
1204 ip6 = ip6cp->ip6c_ip6;
1205 off = ip6cp->ip6c_off;
1206 sa6_src = ip6cp->ip6c_src;
1207 } else {
1208 m = NULL;
1209 ip6 = NULL;
1210 off = 0; /* fool gcc */
1211 sa6_src = &sa6_any;
1212 }
1213
1214 if (ip6) {
1215 struct in_conninfo inc;
1216 /*
1217 * XXX: We assume that when IPV6 is non NULL,
1218 * M and OFF are valid.
1219 */
1220
1221 /* check if we can safely examine src and dst ports */
1222 if (m->m_pkthdr.len < off + sizeof(*thp))
1223 return;
1224
1225 bzero(&th, sizeof(th));
1226 m_copydata(m, off, sizeof(*thp), (caddr_t)&th);
1227
1228 in6_pcbnotify(&tcb, sa, th.th_dport,
1229 (struct sockaddr *)ip6cp->ip6c_src,
1230 th.th_sport, cmd, notify);
1231
1232 inc.inc_fport = th.th_dport;
1233 inc.inc_lport = th.th_sport;
1234 inc.inc6_faddr = ((struct sockaddr_in6 *)sa)->sin6_addr;
1235 inc.inc6_laddr = ip6cp->ip6c_src->sin6_addr;
1236 inc.inc_isipv6 = 1;
1237 syncache_unreach(&inc, &th);
1238 } else
1239 in6_pcbnotify(&tcb, sa, 0, (const struct sockaddr *)sa6_src,
1240 0, cmd, notify);
1241}
1242#endif /* INET6 */
1243
1244
1245/*
1246 * Following is where TCP initial sequence number generation occurs.
1247 *
1248 * There are two places where we must use initial sequence numbers:
1249 * 1. In SYN-ACK packets.
1250 * 2. In SYN packets.
1251 *
1252 * All ISNs for SYN-ACK packets are generated by the syncache. See
1253 * tcp_syncache.c for details.
1254 *
1255 * The ISNs in SYN packets must be monotonic; TIME_WAIT recycling
1256 * depends on this property. In addition, these ISNs should be
1257 * unguessable so as to prevent connection hijacking. To satisfy
1258 * the requirements of this situation, the algorithm outlined in
1259 * RFC 1948 is used to generate sequence numbers.
1260 *
1261 * Implementation details:
1262 *
1263 * Time is based off the system timer, and is corrected so that it
1264 * increases by one megabyte per second. This allows for proper
1265 * recycling on high speed LANs while still leaving over an hour
1266 * before rollover.
1267 *
1268 * net.inet.tcp.isn_reseed_interval controls the number of seconds
1269 * between seeding of isn_secret. This is normally set to zero,
1270 * as reseeding should not be necessary.
1271 *
1272 */
1273
1274#define ISN_BYTES_PER_SECOND 1048576
1275
1276u_char isn_secret[32];
1277int isn_last_reseed;
1278MD5_CTX isn_ctx;
1279
1280tcp_seq
1281tcp_new_isn(tp)
1282 struct tcpcb *tp;
1283{
1284 u_int32_t md5_buffer[4];
1285 tcp_seq new_isn;
1286
1287 /* Seed if this is the first use, reseed if requested. */
1288 if ((isn_last_reseed == 0) || ((tcp_isn_reseed_interval > 0) &&
1289 (((u_int)isn_last_reseed + (u_int)tcp_isn_reseed_interval*hz)
1290 < (u_int)ticks))) {
1291 read_random(&isn_secret, sizeof(isn_secret));
1292 isn_last_reseed = ticks;
1293 }
1294
1295 /* Compute the md5 hash and return the ISN. */
1296 MD5Init(&isn_ctx);
1297 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_fport, sizeof(u_short));
1298 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_lport, sizeof(u_short));
1299#ifdef INET6
1300 if ((tp->t_inpcb->inp_vflag & INP_IPV6) != 0) {
1301 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->in6p_faddr,
1302 sizeof(struct in6_addr));
1303 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->in6p_laddr,
1304 sizeof(struct in6_addr));
1305 } else
1306#endif
1307 {
1308 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_faddr,
1309 sizeof(struct in_addr));
1310 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_laddr,
1311 sizeof(struct in_addr));
1312 }
1313 MD5Update(&isn_ctx, (u_char *) &isn_secret, sizeof(isn_secret));
1314 MD5Final((u_char *) &md5_buffer, &isn_ctx);
1315 new_isn = (tcp_seq) md5_buffer[0];
1316 new_isn += ticks * (ISN_BYTES_PER_SECOND / hz);
1317 return new_isn;
1318}
1319
1320/*
1321 * When a source quench is received, close congestion window
1322 * to one segment. We will gradually open it again as we proceed.
1323 */
1324struct inpcb *
1325tcp_quench(inp, errno)
1326 struct inpcb *inp;
1327 int errno;
1328{
1329 struct tcpcb *tp = intotcpcb(inp);
1330
1331 if (tp)
1332 tp->snd_cwnd = tp->t_maxseg;
1333 return (inp);
1334}
1335
1336/*
1337 * When a specific ICMP unreachable message is received and the
1338 * connection state is SYN-SENT, drop the connection. This behavior
1339 * is controlled by the icmp_may_rst sysctl.
1340 */
1341struct inpcb *
1342tcp_drop_syn_sent(inp, errno)
1343 struct inpcb *inp;
1344 int errno;
1345{
1346 struct tcpcb *tp = intotcpcb(inp);
1347
1348 if (tp && tp->t_state == TCPS_SYN_SENT) {
1349 tcp_drop(tp, errno);
1350 return (struct inpcb *)0;
1351 }
1352 return inp;
1353}
1354
1355/*
1356 * When `need fragmentation' ICMP is received, update our idea of the MSS
1357 * based on the new value in the route. Also nudge TCP to send something,
1358 * since we know the packet we just sent was dropped.
1359 * This duplicates some code in the tcp_mss() function in tcp_input.c.
1360 */
1361struct inpcb *
1362tcp_mtudisc(inp, errno)
1363 struct inpcb *inp;
1364 int errno;
1365{
1366 struct tcpcb *tp = intotcpcb(inp);
1367 struct rtentry *rt;
1368 struct rmxp_tao *taop;
1369 struct socket *so = inp->inp_socket;
1370 int offered;
1371 int mss;
1372#ifdef INET6
1373 int isipv6 = (tp->t_inpcb->inp_vflag & INP_IPV6) != 0;
1374#endif /* INET6 */
1375
1376 if (tp) {
1377#ifdef INET6
1378 if (isipv6)
1379 rt = tcp_rtlookup6(&inp->inp_inc);
1380 else
1381#endif /* INET6 */
1382 rt = tcp_rtlookup(&inp->inp_inc);
1383 if (!rt || !rt->rt_rmx.rmx_mtu) {
1384 tp->t_maxopd = tp->t_maxseg =
1385#ifdef INET6
1386 isipv6 ? tcp_v6mssdflt :
1387#endif /* INET6 */
1388 tcp_mssdflt;
1389 return inp;
1390 }
1391 taop = rmx_taop(rt->rt_rmx);
1392 offered = taop->tao_mssopt;
1393 mss = rt->rt_rmx.rmx_mtu -
1394#ifdef INET6
1395 (isipv6 ?
1396 sizeof(struct ip6_hdr) + sizeof(struct tcphdr) :
1397#endif /* INET6 */
1398 sizeof(struct tcpiphdr)
1399#ifdef INET6
1400 )
1401#endif /* INET6 */
1402 ;
1403
1404 if (offered)
1405 mss = min(mss, offered);
1406 /*
1407 * XXX - The above conditional probably violates the TCP
1408 * spec. The problem is that, since we don't know the
1409 * other end's MSS, we are supposed to use a conservative
1410 * default. But, if we do that, then MTU discovery will
1411 * never actually take place, because the conservative
1412 * default is much less than the MTUs typically seen
1413 * on the Internet today. For the moment, we'll sweep
1414 * this under the carpet.
1415 *
1416 * The conservative default might not actually be a problem
1417 * if the only case this occurs is when sending an initial
1418 * SYN with options and data to a host we've never talked
1419 * to before. Then, they will reply with an MSS value which
1420 * will get recorded and the new parameters should get
1421 * recomputed. For Further Study.
1422 */
1423 if (tp->t_maxopd <= mss)
1424 return inp;
1425 tp->t_maxopd = mss;
1426
1427 if ((tp->t_flags & (TF_REQ_TSTMP|TF_NOOPT)) == TF_REQ_TSTMP &&
1428 (tp->t_flags & TF_RCVD_TSTMP) == TF_RCVD_TSTMP)
1429 mss -= TCPOLEN_TSTAMP_APPA;
1430 if ((tp->t_flags & (TF_REQ_CC|TF_NOOPT)) == TF_REQ_CC &&
1431 (tp->t_flags & TF_RCVD_CC) == TF_RCVD_CC)
1432 mss -= TCPOLEN_CC_APPA;
1433#if (MCLBYTES & (MCLBYTES - 1)) == 0
1434 if (mss > MCLBYTES)
1435 mss &= ~(MCLBYTES-1);
1436#else
1437 if (mss > MCLBYTES)
1438 mss = mss / MCLBYTES * MCLBYTES;
1439#endif
1440 if (so->so_snd.sb_hiwat < mss)
1441 mss = so->so_snd.sb_hiwat;
1442
1443 tp->t_maxseg = mss;
1444
1445 tcpstat.tcps_mturesent++;
1446 tp->t_rtttime = 0;
1447 tp->snd_nxt = tp->snd_una;
1448 tcp_output(tp);
1449 }
1450 return inp;
1451}
1452
1453/*
1454 * Look-up the routing entry to the peer of this inpcb. If no route
1455 * is found and it cannot be allocated, then return NULL. This routine
1456 * is called by TCP routines that access the rmx structure and by tcp_mss
1457 * to get the interface MTU.
1458 */
1459struct rtentry *
1460tcp_rtlookup(inc)
1461 struct in_conninfo *inc;
1462{
1463 struct route *ro;
1464 struct rtentry *rt;
1465
1466 ro = &inc->inc_route;
1467 rt = ro->ro_rt;
1468 if (rt == NULL || !(rt->rt_flags & RTF_UP)) {
1469 /* No route yet, so try to acquire one */
1470 if (inc->inc_faddr.s_addr != INADDR_ANY) {
1471 ro->ro_dst.sa_family = AF_INET;
1472 ro->ro_dst.sa_len = sizeof(struct sockaddr_in);
1473 ((struct sockaddr_in *) &ro->ro_dst)->sin_addr =
1474 inc->inc_faddr;
1475 rtalloc(ro);
1476 rt = ro->ro_rt;
1477 }
1478 }
1479 return rt;
1480}
1481
1482#ifdef INET6
1483struct rtentry *
1484tcp_rtlookup6(inc)
1485 struct in_conninfo *inc;
1486{
1487 struct route_in6 *ro6;
1488 struct rtentry *rt;
1489
1490 ro6 = &inc->inc6_route;
1491 rt = ro6->ro_rt;
1492 if (rt == NULL || !(rt->rt_flags & RTF_UP)) {
1493 /* No route yet, so try to acquire one */
1494 if (!IN6_IS_ADDR_UNSPECIFIED(&inc->inc6_faddr)) {
1495 ro6->ro_dst.sin6_family = AF_INET6;
1496 ro6->ro_dst.sin6_len = sizeof(struct sockaddr_in6);
1497 ro6->ro_dst.sin6_addr = inc->inc6_faddr;
1498 rtalloc((struct route *)ro6);
1499 rt = ro6->ro_rt;
1500 }
1501 }
1502 return rt;
1503}
1504#endif /* INET6 */
1505
1506#ifdef IPSEC
1507/* compute ESP/AH header size for TCP, including outer IP header. */
1508size_t
1509ipsec_hdrsiz_tcp(tp)
1510 struct tcpcb *tp;
1511{
1512 struct inpcb *inp;
1513 struct mbuf *m;
1514 size_t hdrsiz;
1515 struct ip *ip;
1516#ifdef INET6
1517 struct ip6_hdr *ip6;
1518#endif
1519 struct tcphdr *th;
1520
1521 if ((tp == NULL) || ((inp = tp->t_inpcb) == NULL))
1522 return 0;
1523 MGETHDR(m, M_DONTWAIT, MT_DATA);
1524 if (!m)
1525 return 0;
1526
1527#ifdef INET6
1528 if ((inp->inp_vflag & INP_IPV6) != 0) {
1529 ip6 = mtod(m, struct ip6_hdr *);
1530 th = (struct tcphdr *)(ip6 + 1);
1531 m->m_pkthdr.len = m->m_len =
1532 sizeof(struct ip6_hdr) + sizeof(struct tcphdr);
1533 tcpip_fillheaders(inp, ip6, th);
1534 hdrsiz = ipsec6_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp);
1535 } else
1536#endif /* INET6 */
1537 {
1538 ip = mtod(m, struct ip *);
1539 th = (struct tcphdr *)(ip + 1);
1540 m->m_pkthdr.len = m->m_len = sizeof(struct tcpiphdr);
1541 tcpip_fillheaders(inp, ip, th);
1542 hdrsiz = ipsec4_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp);
1543 }
1544
1545 m_free(m);
1546 return hdrsiz;
1547}
1548#endif /*IPSEC*/
1549
1550/*
1551 * Return a pointer to the cached information about the remote host.
1552 * The cached information is stored in the protocol specific part of
1553 * the route metrics.
1554 */
1555struct rmxp_tao *
1556tcp_gettaocache(inc)
1557 struct in_conninfo *inc;
1558{
1559 struct rtentry *rt;
1560
1561#ifdef INET6
1562 if (inc->inc_isipv6)
1563 rt = tcp_rtlookup6(inc);
1564 else
1565#endif /* INET6 */
1566 rt = tcp_rtlookup(inc);
1567
1568 /* Make sure this is a host route and is up. */
1569 if (rt == NULL ||
1570 (rt->rt_flags & (RTF_UP|RTF_HOST)) != (RTF_UP|RTF_HOST))
1571 return NULL;
1572
1573 return rmx_taop(rt->rt_rmx);
1574}
1575
1576/*
1577 * Clear all the TAO cache entries, called from tcp_init.
1578 *
1579 * XXX
1580 * This routine is just an empty one, because we assume that the routing
1581 * routing tables are initialized at the same time when TCP, so there is
1582 * nothing in the cache left over.
1583 */
1584static void
1585tcp_cleartaocache()
1586{
1587}
1588
1589/*
1590 * Move a TCP connection into TIME_WAIT state.
1591 * tcbinfo is unlocked.
1592 * inp is locked, and is unlocked before returning.
1593 */
1594void
1595tcp_twstart(tp)
1596 struct tcpcb *tp;
1597{
1598 struct tcptw *tw;
1599 struct inpcb *inp;
1600 int tw_time, acknow;
1601 struct socket *so;
1602
1603 tw = uma_zalloc(tcptw_zone, M_NOWAIT);
1604 if (tw == NULL) {
1605 tw = tcp_timer_2msl_tw(1);
1606 if (tw == NULL) {
1607 tcp_close(tp);
1608 return;
1609 }
1610 }
1611 inp = tp->t_inpcb;
1612 tw->tw_inpcb = inp;
1613
1614 /*
1615 * Recover last window size sent.
1616 */
1617 tw->last_win = (tp->rcv_adv - tp->rcv_nxt) >> tp->rcv_scale;
1618
1619 /*
1620 * Set t_recent if timestamps are used on the connection.
1621 */
1622 if ((tp->t_flags & (TF_REQ_TSTMP|TF_RCVD_TSTMP|TF_NOOPT)) ==
1623 (TF_REQ_TSTMP|TF_RCVD_TSTMP))
1624 tw->t_recent = tp->ts_recent;
1625 else
1626 tw->t_recent = 0;
1627
1628 tw->snd_nxt = tp->snd_nxt;
1629 tw->rcv_nxt = tp->rcv_nxt;
1630 tw->cc_recv = tp->cc_recv;
1631 tw->cc_send = tp->cc_send;
1632 tw->t_starttime = tp->t_starttime;
1633 tw->tw_time = 0;
1634
1635/* XXX
1636 * If this code will
1637 * be used for fin-wait-2 state also, then we may need
1638 * a ts_recent from the last segment.
1639 */
1640 /* Shorten TIME_WAIT [RFC-1644, p.28] */
1641 if (tp->cc_recv != 0 && (ticks - tp->t_starttime) < tcp_msl) {
1642 tw_time = tp->t_rxtcur * TCPTV_TWTRUNC;
1643 /* For T/TCP client, force ACK now. */
1644 acknow = 1;
1645 } else {
1646 tw_time = 2 * tcp_msl;
1647 acknow = tp->t_flags & TF_ACKNOW;
1648 }
1649 tcp_discardcb(tp);
1650 so = inp->inp_socket;
1651 so->so_pcb = NULL;
1652 tw->tw_cred = crhold(so->so_cred);
1653 tw->tw_so_options = so->so_options;
1654 sotryfree(so);
1655 inp->inp_socket = NULL;
1656 inp->inp_ppcb = (caddr_t)tw;
1657 inp->inp_vflag |= INP_TIMEWAIT;
1658 tcp_timer_2msl_reset(tw, tw_time);
1659 if (acknow)
1660 tcp_twrespond(tw, TH_ACK);
1661 INP_UNLOCK(inp);
1662}
1663
1664struct tcptw *
1665tcp_twclose(struct tcptw *tw, int reuse)
1666{
1667 struct inpcb *inp;
1668
1669 inp = tw->tw_inpcb;
1670 tw->tw_inpcb = NULL;
1671 tcp_timer_2msl_stop(tw);
1672 inp->inp_ppcb = NULL;
1673#ifdef INET6
1674 if (inp->inp_vflag & INP_IPV6PROTO)
1675 in6_pcbdetach(inp);
1676 else
1677#endif
1678 in_pcbdetach(inp);
1679 tcpstat.tcps_closed++;
1680 if (reuse)
1681 return (tw);
1682 uma_zfree(tcptw_zone, tw);
1683 return (NULL);
1684}
1685
1686int
1687tcp_twrespond(struct tcptw *tw, int flags)
1688{
1689 struct inpcb *inp = tw->tw_inpcb;
1690 struct tcphdr *th;
1691 struct mbuf *m;
1692 struct ip *ip = NULL;
1693 u_int8_t *optp;
1694 u_int hdrlen, optlen;
1695 int error;
1696#ifdef INET6
1697 struct ip6_hdr *ip6 = NULL;
1698 int isipv6 = inp->inp_inc.inc_isipv6;
1699#endif
1700
1701 m = m_gethdr(M_DONTWAIT, MT_HEADER);
1702 if (m == NULL)
1703 return (ENOBUFS);
1704 m->m_data += max_linkhdr;
1705
1706#ifdef INET6
1707 if (isipv6) {
1708 hdrlen = sizeof(struct ip6_hdr) + sizeof(struct tcphdr);
1709 ip6 = mtod(m, struct ip6_hdr *);
1710 th = (struct tcphdr *)(ip6 + 1);
1711 tcpip_fillheaders(inp, ip6, th);
1712 } else
1713#endif
1714 {
1715 hdrlen = sizeof(struct tcpiphdr);
1716 ip = mtod(m, struct ip *);
1717 th = (struct tcphdr *)(ip + 1);
1718 tcpip_fillheaders(inp, ip, th);
1719 }
1720 optp = (u_int8_t *)(th + 1);
1721
1722 /*
1723 * Send a timestamp and echo-reply if both our side and our peer
1724 * have sent timestamps in our SYN's and this is not a RST.
1725 */
1726 if (tw->t_recent && flags == TH_ACK) {
1727 u_int32_t *lp = (u_int32_t *)optp;
1728
1729 /* Form timestamp option as shown in appendix A of RFC 1323. */
1730 *lp++ = htonl(TCPOPT_TSTAMP_HDR);
1731 *lp++ = htonl(ticks);
1732 *lp = htonl(tw->t_recent);
1733 optp += TCPOLEN_TSTAMP_APPA;
1734 }
1735
1736 /*
1737 * Send `CC-family' options if needed, and it's not a RST.
1738 */
1739 if (tw->cc_recv != 0 && flags == TH_ACK) {
1740 u_int32_t *lp = (u_int32_t *)optp;
1741
1742 *lp++ = htonl(TCPOPT_CC_HDR(TCPOPT_CC));
1743 *lp = htonl(tw->cc_send);
1744 optp += TCPOLEN_CC_APPA;
1745 }
1746 optlen = optp - (u_int8_t *)(th + 1);
1747
1748 m->m_len = hdrlen + optlen;
1749 m->m_pkthdr.len = m->m_len;
1750
1751 KASSERT(max_linkhdr + m->m_len <= MHLEN, ("tcptw: mbuf too small"));
1752
1753 th->th_seq = htonl(tw->snd_nxt);
1754 th->th_ack = htonl(tw->rcv_nxt);
1755 th->th_off = (sizeof(struct tcphdr) + optlen) >> 2;
1756 th->th_flags = flags;
1757 th->th_win = htons(tw->last_win);
1758
1759#ifdef INET6
1760 if (isipv6) {
1761 th->th_sum = in6_cksum(m, IPPROTO_TCP, sizeof(struct ip6_hdr),
1762 sizeof(struct tcphdr) + optlen);
1763 ip6->ip6_hlim = in6_selecthlim(inp, inp->in6p_route.ro_rt ?
1764 inp->in6p_route.ro_rt->rt_ifp : NULL);
1765 error = ip6_output(m, inp->in6p_outputopts, &inp->in6p_route,
1766 (tw->tw_so_options & SO_DONTROUTE), NULL, NULL, inp);
1767 } else
1768#endif
1769 {
1770 th->th_sum = in_pseudo(ip->ip_src.s_addr, ip->ip_dst.s_addr,
1771 htons(sizeof(struct tcphdr) + optlen + IPPROTO_TCP));
1772 m->m_pkthdr.csum_flags = CSUM_TCP;
1773 m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum);
1774 ip->ip_len = m->m_pkthdr.len;
1775 error = ip_output(m, inp->inp_options, &inp->inp_route,
1776 (tw->tw_so_options & SO_DONTROUTE), NULL, inp);
1777 }
1778 if (flags & TH_ACK)
1779 tcpstat.tcps_sndacks++;
1780 else
1781 tcpstat.tcps_sndctrl++;
1782 tcpstat.tcps_sndtotal++;
1783 return (error);
1784}
1785
1786/*
1787 * TCP BANDWIDTH DELAY PRODUCT WINDOW LIMITING
1788 *
1789 * This code attempts to calculate the bandwidth-delay product as a
1790 * means of determining the optimal window size to maximize bandwidth,
1791 * minimize RTT, and avoid the over-allocation of buffers on interfaces and
1792 * routers. This code also does a fairly good job keeping RTTs in check
1793 * across slow links like modems. We implement an algorithm which is very
1794 * similar (but not meant to be) TCP/Vegas. The code operates on the
1795 * transmitter side of a TCP connection and so only effects the transmit
1796 * side of the connection.
1797 *
1798 * BACKGROUND: TCP makes no provision for the management of buffer space
1799 * at the end points or at the intermediate routers and switches. A TCP
1800 * stream, whether using NewReno or not, will eventually buffer as
1801 * many packets as it is able and the only reason this typically works is
1802 * due to the fairly small default buffers made available for a connection
1803 * (typicaly 16K or 32K). As machines use larger windows and/or window
1804 * scaling it is now fairly easy for even a single TCP connection to blow-out
1805 * all available buffer space not only on the local interface, but on
1806 * intermediate routers and switches as well. NewReno makes a misguided
1807 * attempt to 'solve' this problem by waiting for an actual failure to occur,
1808 * then backing off, then steadily increasing the window again until another
1809 * failure occurs, ad-infinitum. This results in terrible oscillation that
1810 * is only made worse as network loads increase and the idea of intentionally
1811 * blowing out network buffers is, frankly, a terrible way to manage network
1812 * resources.
1813 *
1814 * It is far better to limit the transmit window prior to the failure
1815 * condition being achieved. There are two general ways to do this: First
1816 * you can 'scan' through different transmit window sizes and locate the
1817 * point where the RTT stops increasing, indicating that you have filled the
1818 * pipe, then scan backwards until you note that RTT stops decreasing, then
1819 * repeat ad-infinitum. This method works in principle but has severe
1820 * implementation issues due to RTT variances, timer granularity, and
1821 * instability in the algorithm which can lead to many false positives and
1822 * create oscillations as well as interact badly with other TCP streams
1823 * implementing the same algorithm.
1824 *
1825 * The second method is to limit the window to the bandwidth delay product
1826 * of the link. This is the method we implement. RTT variances and our
1827 * own manipulation of the congestion window, bwnd, can potentially
1828 * destabilize the algorithm. For this reason we have to stabilize the
1829 * elements used to calculate the window. We do this by using the minimum
1830 * observed RTT, the long term average of the observed bandwidth, and
1831 * by adding two segments worth of slop. It isn't perfect but it is able
1832 * to react to changing conditions and gives us a very stable basis on
1833 * which to extend the algorithm.
1834 */
1835void
1836tcp_xmit_bandwidth_limit(struct tcpcb *tp, tcp_seq ack_seq)
1837{
1838 u_long bw;
1839 u_long bwnd;
1840 int save_ticks;
1841
1842 /*
1843 * If inflight_enable is disabled in the middle of a tcp connection,
1844 * make sure snd_bwnd is effectively disabled.
1845 */
1846 if (tcp_inflight_enable == 0) {
1847 tp->snd_bwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT;
1848 tp->snd_bandwidth = 0;
1849 return;
1850 }
1851
1852 /*
1853 * Figure out the bandwidth. Due to the tick granularity this
1854 * is a very rough number and it MUST be averaged over a fairly
1855 * long period of time. XXX we need to take into account a link
1856 * that is not using all available bandwidth, but for now our
1857 * slop will ramp us up if this case occurs and the bandwidth later
1858 * increases.
1859 *
1860 * Note: if ticks rollover 'bw' may wind up negative. We must
1861 * effectively reset t_bw_rtttime for this case.
1862 */
1863 save_ticks = ticks;
1864 if ((u_int)(save_ticks - tp->t_bw_rtttime) < 1)
1865 return;
1866
1867 bw = (int64_t)(ack_seq - tp->t_bw_rtseq) * hz /
1868 (save_ticks - tp->t_bw_rtttime);
1869 tp->t_bw_rtttime = save_ticks;
1870 tp->t_bw_rtseq = ack_seq;
1871 if (tp->t_bw_rtttime == 0 || (int)bw < 0)
1872 return;
1873 bw = ((int64_t)tp->snd_bandwidth * 15 + bw) >> 4;
1874
1875 tp->snd_bandwidth = bw;
1876
1877 /*
1878 * Calculate the semi-static bandwidth delay product, plus two maximal
1879 * segments. The additional slop puts us squarely in the sweet
1880 * spot and also handles the bandwidth run-up case and stabilization.
1881 * Without the slop we could be locking ourselves into a lower
1882 * bandwidth.
1883 *
1884 * Situations Handled:
1885 * (1) Prevents over-queueing of packets on LANs, especially on
1886 * high speed LANs, allowing larger TCP buffers to be
1887 * specified, and also does a good job preventing
1888 * over-queueing of packets over choke points like modems
1889 * (at least for the transmit side).
1890 *
1891 * (2) Is able to handle changing network loads (bandwidth
1892 * drops so bwnd drops, bandwidth increases so bwnd
1893 * increases).
1894 *
1895 * (3) Theoretically should stabilize in the face of multiple
1896 * connections implementing the same algorithm (this may need
1897 * a little work).
1898 *
1899 * (4) Stability value (defaults to 20 = 2 maximal packets) can
1900 * be adjusted with a sysctl but typically only needs to be
1901 * on very slow connections. A value no smaller then 5
1902 * should be used, but only reduce this default if you have
1903 * no other choice.
1904 */
1905#define USERTT ((tp->t_srtt + tp->t_rttbest) / 2)
1906 bwnd = (int64_t)bw * USERTT / (hz << TCP_RTT_SHIFT) + tcp_inflight_stab * tp->t_maxseg / 10;
1907#undef USERTT
1908
1909 if (tcp_inflight_debug > 0) {
1910 static int ltime;
1911 if ((u_int)(ticks - ltime) >= hz / tcp_inflight_debug) {
1912 ltime = ticks;
1913 printf("%p bw %ld rttbest %d srtt %d bwnd %ld\n",
1914 tp,
1915 bw,
1916 tp->t_rttbest,
1917 tp->t_srtt,
1918 bwnd
1919 );
1920 }
1921 }
1922 if ((long)bwnd < tcp_inflight_min)
1923 bwnd = tcp_inflight_min;
1924 if (bwnd > tcp_inflight_max)
1925 bwnd = tcp_inflight_max;
1926 if ((long)bwnd < tp->t_maxseg * 2)
1927 bwnd = tp->t_maxseg * 2;
1928 tp->snd_bwnd = bwnd;
1929}
1930
| 944 INP_UNLOCK(inp);
945 }
946 INP_INFO_RUNLOCK(&tcbinfo);
947 splx(s);
948 n = i;
949
950 error = 0;
951 for (i = 0; i < n; i++) {
952 inp = inp_list[i];
953 if (inp->inp_gencnt <= gencnt) {
954 struct xtcpcb xt;
955 caddr_t inp_ppcb;
956 xt.xt_len = sizeof xt;
957 /* XXX should avoid extra copy */
958 bcopy(inp, &xt.xt_inp, sizeof *inp);
959 inp_ppcb = inp->inp_ppcb;
960 if (inp_ppcb == NULL)
961 bzero((char *) &xt.xt_tp, sizeof xt.xt_tp);
962 else if (inp->inp_vflag & INP_TIMEWAIT) {
963 bzero((char *) &xt.xt_tp, sizeof xt.xt_tp);
964 xt.xt_tp.t_state = TCPS_TIME_WAIT;
965 } else
966 bcopy(inp_ppcb, &xt.xt_tp, sizeof xt.xt_tp);
967 if (inp->inp_socket)
968 sotoxsocket(inp->inp_socket, &xt.xt_socket);
969 else {
970 bzero(&xt.xt_socket, sizeof xt.xt_socket);
971 xt.xt_socket.xso_protocol = IPPROTO_TCP;
972 }
973 xt.xt_inp.inp_gencnt = inp->inp_gencnt;
974 error = SYSCTL_OUT(req, &xt, sizeof xt);
975 }
976 }
977 if (!error) {
978 /*
979 * Give the user an updated idea of our state.
980 * If the generation differs from what we told
981 * her before, she knows that something happened
982 * while we were processing this request, and it
983 * might be necessary to retry.
984 */
985 s = splnet();
986 INP_INFO_RLOCK(&tcbinfo);
987 xig.xig_gen = tcbinfo.ipi_gencnt;
988 xig.xig_sogen = so_gencnt;
989 xig.xig_count = tcbinfo.ipi_count;
990 INP_INFO_RUNLOCK(&tcbinfo);
991 splx(s);
992 error = SYSCTL_OUT(req, &xig, sizeof xig);
993 }
994 free(inp_list, M_TEMP);
995 return error;
996}
997
998SYSCTL_PROC(_net_inet_tcp, TCPCTL_PCBLIST, pcblist, CTLFLAG_RD, 0, 0,
999 tcp_pcblist, "S,xtcpcb", "List of active TCP connections");
1000
1001static int
1002tcp_getcred(SYSCTL_HANDLER_ARGS)
1003{
1004 struct xucred xuc;
1005 struct sockaddr_in addrs[2];
1006 struct inpcb *inp;
1007 int error, s;
1008
1009 error = suser_cred(req->td->td_ucred, PRISON_ROOT);
1010 if (error)
1011 return (error);
1012 error = SYSCTL_IN(req, addrs, sizeof(addrs));
1013 if (error)
1014 return (error);
1015 s = splnet();
1016 INP_INFO_RLOCK(&tcbinfo);
1017 inp = in_pcblookup_hash(&tcbinfo, addrs[1].sin_addr, addrs[1].sin_port,
1018 addrs[0].sin_addr, addrs[0].sin_port, 0, NULL);
1019 if (inp == NULL) {
1020 error = ENOENT;
1021 goto outunlocked;
1022 }
1023 INP_LOCK(inp);
1024 if (inp->inp_socket == NULL) {
1025 error = ENOENT;
1026 goto out;
1027 }
1028 error = cr_canseesocket(req->td->td_ucred, inp->inp_socket);
1029 if (error)
1030 goto out;
1031 cru2x(inp->inp_socket->so_cred, &xuc);
1032out:
1033 INP_UNLOCK(inp);
1034outunlocked:
1035 INP_INFO_RUNLOCK(&tcbinfo);
1036 splx(s);
1037 if (error == 0)
1038 error = SYSCTL_OUT(req, &xuc, sizeof(struct xucred));
1039 return (error);
1040}
1041
1042SYSCTL_PROC(_net_inet_tcp, OID_AUTO, getcred,
1043 CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_PRISON, 0, 0,
1044 tcp_getcred, "S,xucred", "Get the xucred of a TCP connection");
1045
1046#ifdef INET6
1047static int
1048tcp6_getcred(SYSCTL_HANDLER_ARGS)
1049{
1050 struct xucred xuc;
1051 struct sockaddr_in6 addrs[2];
1052 struct inpcb *inp;
1053 int error, s, mapped = 0;
1054
1055 error = suser_cred(req->td->td_ucred, PRISON_ROOT);
1056 if (error)
1057 return (error);
1058 error = SYSCTL_IN(req, addrs, sizeof(addrs));
1059 if (error)
1060 return (error);
1061 if (IN6_IS_ADDR_V4MAPPED(&addrs[0].sin6_addr)) {
1062 if (IN6_IS_ADDR_V4MAPPED(&addrs[1].sin6_addr))
1063 mapped = 1;
1064 else
1065 return (EINVAL);
1066 }
1067 s = splnet();
1068 INP_INFO_RLOCK(&tcbinfo);
1069 if (mapped == 1)
1070 inp = in_pcblookup_hash(&tcbinfo,
1071 *(struct in_addr *)&addrs[1].sin6_addr.s6_addr[12],
1072 addrs[1].sin6_port,
1073 *(struct in_addr *)&addrs[0].sin6_addr.s6_addr[12],
1074 addrs[0].sin6_port,
1075 0, NULL);
1076 else
1077 inp = in6_pcblookup_hash(&tcbinfo, &addrs[1].sin6_addr,
1078 addrs[1].sin6_port,
1079 &addrs[0].sin6_addr, addrs[0].sin6_port,
1080 0, NULL);
1081 if (inp == NULL) {
1082 error = ENOENT;
1083 goto outunlocked;
1084 }
1085 INP_LOCK(inp);
1086 if (inp->inp_socket == NULL) {
1087 error = ENOENT;
1088 goto out;
1089 }
1090 error = cr_canseesocket(req->td->td_ucred, inp->inp_socket);
1091 if (error)
1092 goto out;
1093 cru2x(inp->inp_socket->so_cred, &xuc);
1094out:
1095 INP_UNLOCK(inp);
1096outunlocked:
1097 INP_INFO_RUNLOCK(&tcbinfo);
1098 splx(s);
1099 if (error == 0)
1100 error = SYSCTL_OUT(req, &xuc, sizeof(struct xucred));
1101 return (error);
1102}
1103
1104SYSCTL_PROC(_net_inet6_tcp6, OID_AUTO, getcred,
1105 CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_PRISON, 0, 0,
1106 tcp6_getcred, "S,xucred", "Get the xucred of a TCP6 connection");
1107#endif
1108
1109
1110void
1111tcp_ctlinput(cmd, sa, vip)
1112 int cmd;
1113 struct sockaddr *sa;
1114 void *vip;
1115{
1116 struct ip *ip = vip;
1117 struct tcphdr *th;
1118 struct in_addr faddr;
1119 struct inpcb *inp;
1120 struct tcpcb *tp;
1121 struct inpcb *(*notify)(struct inpcb *, int) = tcp_notify;
1122 tcp_seq icmp_seq;
1123 int s;
1124
1125 faddr = ((struct sockaddr_in *)sa)->sin_addr;
1126 if (sa->sa_family != AF_INET || faddr.s_addr == INADDR_ANY)
1127 return;
1128
1129 if (cmd == PRC_QUENCH)
1130 notify = tcp_quench;
1131 else if (icmp_may_rst && (cmd == PRC_UNREACH_ADMIN_PROHIB ||
1132 cmd == PRC_UNREACH_PORT || cmd == PRC_TIMXCEED_INTRANS) && ip)
1133 notify = tcp_drop_syn_sent;
1134 else if (cmd == PRC_MSGSIZE)
1135 notify = tcp_mtudisc;
1136 else if (PRC_IS_REDIRECT(cmd)) {
1137 ip = 0;
1138 notify = in_rtchange;
1139 } else if (cmd == PRC_HOSTDEAD)
1140 ip = 0;
1141 else if ((unsigned)cmd > PRC_NCMDS || inetctlerrmap[cmd] == 0)
1142 return;
1143 if (ip) {
1144 s = splnet();
1145 th = (struct tcphdr *)((caddr_t)ip
1146 + (ip->ip_hl << 2));
1147 INP_INFO_WLOCK(&tcbinfo);
1148 inp = in_pcblookup_hash(&tcbinfo, faddr, th->th_dport,
1149 ip->ip_src, th->th_sport, 0, NULL);
1150 if (inp != NULL) {
1151 INP_LOCK(inp);
1152 if (inp->inp_socket != NULL) {
1153 icmp_seq = htonl(th->th_seq);
1154 tp = intotcpcb(inp);
1155 if (SEQ_GEQ(icmp_seq, tp->snd_una) &&
1156 SEQ_LT(icmp_seq, tp->snd_max))
1157 inp = (*notify)(inp, inetctlerrmap[cmd]);
1158 }
1159 if (inp)
1160 INP_UNLOCK(inp);
1161 } else {
1162 struct in_conninfo inc;
1163
1164 inc.inc_fport = th->th_dport;
1165 inc.inc_lport = th->th_sport;
1166 inc.inc_faddr = faddr;
1167 inc.inc_laddr = ip->ip_src;
1168#ifdef INET6
1169 inc.inc_isipv6 = 0;
1170#endif
1171 syncache_unreach(&inc, th);
1172 }
1173 INP_INFO_WUNLOCK(&tcbinfo);
1174 splx(s);
1175 } else
1176 in_pcbnotifyall(&tcbinfo, faddr, inetctlerrmap[cmd], notify);
1177}
1178
1179#ifdef INET6
1180void
1181tcp6_ctlinput(cmd, sa, d)
1182 int cmd;
1183 struct sockaddr *sa;
1184 void *d;
1185{
1186 struct tcphdr th;
1187 struct inpcb *(*notify)(struct inpcb *, int) = tcp_notify;
1188 struct ip6_hdr *ip6;
1189 struct mbuf *m;
1190 struct ip6ctlparam *ip6cp = NULL;
1191 const struct sockaddr_in6 *sa6_src = NULL;
1192 int off;
1193 struct tcp_portonly {
1194 u_int16_t th_sport;
1195 u_int16_t th_dport;
1196 } *thp;
1197
1198 if (sa->sa_family != AF_INET6 ||
1199 sa->sa_len != sizeof(struct sockaddr_in6))
1200 return;
1201
1202 if (cmd == PRC_QUENCH)
1203 notify = tcp_quench;
1204 else if (cmd == PRC_MSGSIZE)
1205 notify = tcp_mtudisc;
1206 else if (!PRC_IS_REDIRECT(cmd) &&
1207 ((unsigned)cmd > PRC_NCMDS || inet6ctlerrmap[cmd] == 0))
1208 return;
1209
1210 /* if the parameter is from icmp6, decode it. */
1211 if (d != NULL) {
1212 ip6cp = (struct ip6ctlparam *)d;
1213 m = ip6cp->ip6c_m;
1214 ip6 = ip6cp->ip6c_ip6;
1215 off = ip6cp->ip6c_off;
1216 sa6_src = ip6cp->ip6c_src;
1217 } else {
1218 m = NULL;
1219 ip6 = NULL;
1220 off = 0; /* fool gcc */
1221 sa6_src = &sa6_any;
1222 }
1223
1224 if (ip6) {
1225 struct in_conninfo inc;
1226 /*
1227 * XXX: We assume that when IPV6 is non NULL,
1228 * M and OFF are valid.
1229 */
1230
1231 /* check if we can safely examine src and dst ports */
1232 if (m->m_pkthdr.len < off + sizeof(*thp))
1233 return;
1234
1235 bzero(&th, sizeof(th));
1236 m_copydata(m, off, sizeof(*thp), (caddr_t)&th);
1237
1238 in6_pcbnotify(&tcb, sa, th.th_dport,
1239 (struct sockaddr *)ip6cp->ip6c_src,
1240 th.th_sport, cmd, notify);
1241
1242 inc.inc_fport = th.th_dport;
1243 inc.inc_lport = th.th_sport;
1244 inc.inc6_faddr = ((struct sockaddr_in6 *)sa)->sin6_addr;
1245 inc.inc6_laddr = ip6cp->ip6c_src->sin6_addr;
1246 inc.inc_isipv6 = 1;
1247 syncache_unreach(&inc, &th);
1248 } else
1249 in6_pcbnotify(&tcb, sa, 0, (const struct sockaddr *)sa6_src,
1250 0, cmd, notify);
1251}
1252#endif /* INET6 */
1253
1254
1255/*
1256 * Following is where TCP initial sequence number generation occurs.
1257 *
1258 * There are two places where we must use initial sequence numbers:
1259 * 1. In SYN-ACK packets.
1260 * 2. In SYN packets.
1261 *
1262 * All ISNs for SYN-ACK packets are generated by the syncache. See
1263 * tcp_syncache.c for details.
1264 *
1265 * The ISNs in SYN packets must be monotonic; TIME_WAIT recycling
1266 * depends on this property. In addition, these ISNs should be
1267 * unguessable so as to prevent connection hijacking. To satisfy
1268 * the requirements of this situation, the algorithm outlined in
1269 * RFC 1948 is used to generate sequence numbers.
1270 *
1271 * Implementation details:
1272 *
1273 * Time is based off the system timer, and is corrected so that it
1274 * increases by one megabyte per second. This allows for proper
1275 * recycling on high speed LANs while still leaving over an hour
1276 * before rollover.
1277 *
1278 * net.inet.tcp.isn_reseed_interval controls the number of seconds
1279 * between seeding of isn_secret. This is normally set to zero,
1280 * as reseeding should not be necessary.
1281 *
1282 */
1283
1284#define ISN_BYTES_PER_SECOND 1048576
1285
1286u_char isn_secret[32];
1287int isn_last_reseed;
1288MD5_CTX isn_ctx;
1289
1290tcp_seq
1291tcp_new_isn(tp)
1292 struct tcpcb *tp;
1293{
1294 u_int32_t md5_buffer[4];
1295 tcp_seq new_isn;
1296
1297 /* Seed if this is the first use, reseed if requested. */
1298 if ((isn_last_reseed == 0) || ((tcp_isn_reseed_interval > 0) &&
1299 (((u_int)isn_last_reseed + (u_int)tcp_isn_reseed_interval*hz)
1300 < (u_int)ticks))) {
1301 read_random(&isn_secret, sizeof(isn_secret));
1302 isn_last_reseed = ticks;
1303 }
1304
1305 /* Compute the md5 hash and return the ISN. */
1306 MD5Init(&isn_ctx);
1307 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_fport, sizeof(u_short));
1308 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_lport, sizeof(u_short));
1309#ifdef INET6
1310 if ((tp->t_inpcb->inp_vflag & INP_IPV6) != 0) {
1311 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->in6p_faddr,
1312 sizeof(struct in6_addr));
1313 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->in6p_laddr,
1314 sizeof(struct in6_addr));
1315 } else
1316#endif
1317 {
1318 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_faddr,
1319 sizeof(struct in_addr));
1320 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_laddr,
1321 sizeof(struct in_addr));
1322 }
1323 MD5Update(&isn_ctx, (u_char *) &isn_secret, sizeof(isn_secret));
1324 MD5Final((u_char *) &md5_buffer, &isn_ctx);
1325 new_isn = (tcp_seq) md5_buffer[0];
1326 new_isn += ticks * (ISN_BYTES_PER_SECOND / hz);
1327 return new_isn;
1328}
1329
1330/*
1331 * When a source quench is received, close congestion window
1332 * to one segment. We will gradually open it again as we proceed.
1333 */
1334struct inpcb *
1335tcp_quench(inp, errno)
1336 struct inpcb *inp;
1337 int errno;
1338{
1339 struct tcpcb *tp = intotcpcb(inp);
1340
1341 if (tp)
1342 tp->snd_cwnd = tp->t_maxseg;
1343 return (inp);
1344}
1345
1346/*
1347 * When a specific ICMP unreachable message is received and the
1348 * connection state is SYN-SENT, drop the connection. This behavior
1349 * is controlled by the icmp_may_rst sysctl.
1350 */
1351struct inpcb *
1352tcp_drop_syn_sent(inp, errno)
1353 struct inpcb *inp;
1354 int errno;
1355{
1356 struct tcpcb *tp = intotcpcb(inp);
1357
1358 if (tp && tp->t_state == TCPS_SYN_SENT) {
1359 tcp_drop(tp, errno);
1360 return (struct inpcb *)0;
1361 }
1362 return inp;
1363}
1364
1365/*
1366 * When `need fragmentation' ICMP is received, update our idea of the MSS
1367 * based on the new value in the route. Also nudge TCP to send something,
1368 * since we know the packet we just sent was dropped.
1369 * This duplicates some code in the tcp_mss() function in tcp_input.c.
1370 */
1371struct inpcb *
1372tcp_mtudisc(inp, errno)
1373 struct inpcb *inp;
1374 int errno;
1375{
1376 struct tcpcb *tp = intotcpcb(inp);
1377 struct rtentry *rt;
1378 struct rmxp_tao *taop;
1379 struct socket *so = inp->inp_socket;
1380 int offered;
1381 int mss;
1382#ifdef INET6
1383 int isipv6 = (tp->t_inpcb->inp_vflag & INP_IPV6) != 0;
1384#endif /* INET6 */
1385
1386 if (tp) {
1387#ifdef INET6
1388 if (isipv6)
1389 rt = tcp_rtlookup6(&inp->inp_inc);
1390 else
1391#endif /* INET6 */
1392 rt = tcp_rtlookup(&inp->inp_inc);
1393 if (!rt || !rt->rt_rmx.rmx_mtu) {
1394 tp->t_maxopd = tp->t_maxseg =
1395#ifdef INET6
1396 isipv6 ? tcp_v6mssdflt :
1397#endif /* INET6 */
1398 tcp_mssdflt;
1399 return inp;
1400 }
1401 taop = rmx_taop(rt->rt_rmx);
1402 offered = taop->tao_mssopt;
1403 mss = rt->rt_rmx.rmx_mtu -
1404#ifdef INET6
1405 (isipv6 ?
1406 sizeof(struct ip6_hdr) + sizeof(struct tcphdr) :
1407#endif /* INET6 */
1408 sizeof(struct tcpiphdr)
1409#ifdef INET6
1410 )
1411#endif /* INET6 */
1412 ;
1413
1414 if (offered)
1415 mss = min(mss, offered);
1416 /*
1417 * XXX - The above conditional probably violates the TCP
1418 * spec. The problem is that, since we don't know the
1419 * other end's MSS, we are supposed to use a conservative
1420 * default. But, if we do that, then MTU discovery will
1421 * never actually take place, because the conservative
1422 * default is much less than the MTUs typically seen
1423 * on the Internet today. For the moment, we'll sweep
1424 * this under the carpet.
1425 *
1426 * The conservative default might not actually be a problem
1427 * if the only case this occurs is when sending an initial
1428 * SYN with options and data to a host we've never talked
1429 * to before. Then, they will reply with an MSS value which
1430 * will get recorded and the new parameters should get
1431 * recomputed. For Further Study.
1432 */
1433 if (tp->t_maxopd <= mss)
1434 return inp;
1435 tp->t_maxopd = mss;
1436
1437 if ((tp->t_flags & (TF_REQ_TSTMP|TF_NOOPT)) == TF_REQ_TSTMP &&
1438 (tp->t_flags & TF_RCVD_TSTMP) == TF_RCVD_TSTMP)
1439 mss -= TCPOLEN_TSTAMP_APPA;
1440 if ((tp->t_flags & (TF_REQ_CC|TF_NOOPT)) == TF_REQ_CC &&
1441 (tp->t_flags & TF_RCVD_CC) == TF_RCVD_CC)
1442 mss -= TCPOLEN_CC_APPA;
1443#if (MCLBYTES & (MCLBYTES - 1)) == 0
1444 if (mss > MCLBYTES)
1445 mss &= ~(MCLBYTES-1);
1446#else
1447 if (mss > MCLBYTES)
1448 mss = mss / MCLBYTES * MCLBYTES;
1449#endif
1450 if (so->so_snd.sb_hiwat < mss)
1451 mss = so->so_snd.sb_hiwat;
1452
1453 tp->t_maxseg = mss;
1454
1455 tcpstat.tcps_mturesent++;
1456 tp->t_rtttime = 0;
1457 tp->snd_nxt = tp->snd_una;
1458 tcp_output(tp);
1459 }
1460 return inp;
1461}
1462
1463/*
1464 * Look-up the routing entry to the peer of this inpcb. If no route
1465 * is found and it cannot be allocated, then return NULL. This routine
1466 * is called by TCP routines that access the rmx structure and by tcp_mss
1467 * to get the interface MTU.
1468 */
1469struct rtentry *
1470tcp_rtlookup(inc)
1471 struct in_conninfo *inc;
1472{
1473 struct route *ro;
1474 struct rtentry *rt;
1475
1476 ro = &inc->inc_route;
1477 rt = ro->ro_rt;
1478 if (rt == NULL || !(rt->rt_flags & RTF_UP)) {
1479 /* No route yet, so try to acquire one */
1480 if (inc->inc_faddr.s_addr != INADDR_ANY) {
1481 ro->ro_dst.sa_family = AF_INET;
1482 ro->ro_dst.sa_len = sizeof(struct sockaddr_in);
1483 ((struct sockaddr_in *) &ro->ro_dst)->sin_addr =
1484 inc->inc_faddr;
1485 rtalloc(ro);
1486 rt = ro->ro_rt;
1487 }
1488 }
1489 return rt;
1490}
1491
1492#ifdef INET6
1493struct rtentry *
1494tcp_rtlookup6(inc)
1495 struct in_conninfo *inc;
1496{
1497 struct route_in6 *ro6;
1498 struct rtentry *rt;
1499
1500 ro6 = &inc->inc6_route;
1501 rt = ro6->ro_rt;
1502 if (rt == NULL || !(rt->rt_flags & RTF_UP)) {
1503 /* No route yet, so try to acquire one */
1504 if (!IN6_IS_ADDR_UNSPECIFIED(&inc->inc6_faddr)) {
1505 ro6->ro_dst.sin6_family = AF_INET6;
1506 ro6->ro_dst.sin6_len = sizeof(struct sockaddr_in6);
1507 ro6->ro_dst.sin6_addr = inc->inc6_faddr;
1508 rtalloc((struct route *)ro6);
1509 rt = ro6->ro_rt;
1510 }
1511 }
1512 return rt;
1513}
1514#endif /* INET6 */
1515
1516#ifdef IPSEC
1517/* compute ESP/AH header size for TCP, including outer IP header. */
1518size_t
1519ipsec_hdrsiz_tcp(tp)
1520 struct tcpcb *tp;
1521{
1522 struct inpcb *inp;
1523 struct mbuf *m;
1524 size_t hdrsiz;
1525 struct ip *ip;
1526#ifdef INET6
1527 struct ip6_hdr *ip6;
1528#endif
1529 struct tcphdr *th;
1530
1531 if ((tp == NULL) || ((inp = tp->t_inpcb) == NULL))
1532 return 0;
1533 MGETHDR(m, M_DONTWAIT, MT_DATA);
1534 if (!m)
1535 return 0;
1536
1537#ifdef INET6
1538 if ((inp->inp_vflag & INP_IPV6) != 0) {
1539 ip6 = mtod(m, struct ip6_hdr *);
1540 th = (struct tcphdr *)(ip6 + 1);
1541 m->m_pkthdr.len = m->m_len =
1542 sizeof(struct ip6_hdr) + sizeof(struct tcphdr);
1543 tcpip_fillheaders(inp, ip6, th);
1544 hdrsiz = ipsec6_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp);
1545 } else
1546#endif /* INET6 */
1547 {
1548 ip = mtod(m, struct ip *);
1549 th = (struct tcphdr *)(ip + 1);
1550 m->m_pkthdr.len = m->m_len = sizeof(struct tcpiphdr);
1551 tcpip_fillheaders(inp, ip, th);
1552 hdrsiz = ipsec4_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp);
1553 }
1554
1555 m_free(m);
1556 return hdrsiz;
1557}
1558#endif /*IPSEC*/
1559
1560/*
1561 * Return a pointer to the cached information about the remote host.
1562 * The cached information is stored in the protocol specific part of
1563 * the route metrics.
1564 */
1565struct rmxp_tao *
1566tcp_gettaocache(inc)
1567 struct in_conninfo *inc;
1568{
1569 struct rtentry *rt;
1570
1571#ifdef INET6
1572 if (inc->inc_isipv6)
1573 rt = tcp_rtlookup6(inc);
1574 else
1575#endif /* INET6 */
1576 rt = tcp_rtlookup(inc);
1577
1578 /* Make sure this is a host route and is up. */
1579 if (rt == NULL ||
1580 (rt->rt_flags & (RTF_UP|RTF_HOST)) != (RTF_UP|RTF_HOST))
1581 return NULL;
1582
1583 return rmx_taop(rt->rt_rmx);
1584}
1585
1586/*
1587 * Clear all the TAO cache entries, called from tcp_init.
1588 *
1589 * XXX
1590 * This routine is just an empty one, because we assume that the routing
1591 * routing tables are initialized at the same time when TCP, so there is
1592 * nothing in the cache left over.
1593 */
1594static void
1595tcp_cleartaocache()
1596{
1597}
1598
1599/*
1600 * Move a TCP connection into TIME_WAIT state.
1601 * tcbinfo is unlocked.
1602 * inp is locked, and is unlocked before returning.
1603 */
1604void
1605tcp_twstart(tp)
1606 struct tcpcb *tp;
1607{
1608 struct tcptw *tw;
1609 struct inpcb *inp;
1610 int tw_time, acknow;
1611 struct socket *so;
1612
1613 tw = uma_zalloc(tcptw_zone, M_NOWAIT);
1614 if (tw == NULL) {
1615 tw = tcp_timer_2msl_tw(1);
1616 if (tw == NULL) {
1617 tcp_close(tp);
1618 return;
1619 }
1620 }
1621 inp = tp->t_inpcb;
1622 tw->tw_inpcb = inp;
1623
1624 /*
1625 * Recover last window size sent.
1626 */
1627 tw->last_win = (tp->rcv_adv - tp->rcv_nxt) >> tp->rcv_scale;
1628
1629 /*
1630 * Set t_recent if timestamps are used on the connection.
1631 */
1632 if ((tp->t_flags & (TF_REQ_TSTMP|TF_RCVD_TSTMP|TF_NOOPT)) ==
1633 (TF_REQ_TSTMP|TF_RCVD_TSTMP))
1634 tw->t_recent = tp->ts_recent;
1635 else
1636 tw->t_recent = 0;
1637
1638 tw->snd_nxt = tp->snd_nxt;
1639 tw->rcv_nxt = tp->rcv_nxt;
1640 tw->cc_recv = tp->cc_recv;
1641 tw->cc_send = tp->cc_send;
1642 tw->t_starttime = tp->t_starttime;
1643 tw->tw_time = 0;
1644
1645/* XXX
1646 * If this code will
1647 * be used for fin-wait-2 state also, then we may need
1648 * a ts_recent from the last segment.
1649 */
1650 /* Shorten TIME_WAIT [RFC-1644, p.28] */
1651 if (tp->cc_recv != 0 && (ticks - tp->t_starttime) < tcp_msl) {
1652 tw_time = tp->t_rxtcur * TCPTV_TWTRUNC;
1653 /* For T/TCP client, force ACK now. */
1654 acknow = 1;
1655 } else {
1656 tw_time = 2 * tcp_msl;
1657 acknow = tp->t_flags & TF_ACKNOW;
1658 }
1659 tcp_discardcb(tp);
1660 so = inp->inp_socket;
1661 so->so_pcb = NULL;
1662 tw->tw_cred = crhold(so->so_cred);
1663 tw->tw_so_options = so->so_options;
1664 sotryfree(so);
1665 inp->inp_socket = NULL;
1666 inp->inp_ppcb = (caddr_t)tw;
1667 inp->inp_vflag |= INP_TIMEWAIT;
1668 tcp_timer_2msl_reset(tw, tw_time);
1669 if (acknow)
1670 tcp_twrespond(tw, TH_ACK);
1671 INP_UNLOCK(inp);
1672}
1673
1674struct tcptw *
1675tcp_twclose(struct tcptw *tw, int reuse)
1676{
1677 struct inpcb *inp;
1678
1679 inp = tw->tw_inpcb;
1680 tw->tw_inpcb = NULL;
1681 tcp_timer_2msl_stop(tw);
1682 inp->inp_ppcb = NULL;
1683#ifdef INET6
1684 if (inp->inp_vflag & INP_IPV6PROTO)
1685 in6_pcbdetach(inp);
1686 else
1687#endif
1688 in_pcbdetach(inp);
1689 tcpstat.tcps_closed++;
1690 if (reuse)
1691 return (tw);
1692 uma_zfree(tcptw_zone, tw);
1693 return (NULL);
1694}
1695
1696int
1697tcp_twrespond(struct tcptw *tw, int flags)
1698{
1699 struct inpcb *inp = tw->tw_inpcb;
1700 struct tcphdr *th;
1701 struct mbuf *m;
1702 struct ip *ip = NULL;
1703 u_int8_t *optp;
1704 u_int hdrlen, optlen;
1705 int error;
1706#ifdef INET6
1707 struct ip6_hdr *ip6 = NULL;
1708 int isipv6 = inp->inp_inc.inc_isipv6;
1709#endif
1710
1711 m = m_gethdr(M_DONTWAIT, MT_HEADER);
1712 if (m == NULL)
1713 return (ENOBUFS);
1714 m->m_data += max_linkhdr;
1715
1716#ifdef INET6
1717 if (isipv6) {
1718 hdrlen = sizeof(struct ip6_hdr) + sizeof(struct tcphdr);
1719 ip6 = mtod(m, struct ip6_hdr *);
1720 th = (struct tcphdr *)(ip6 + 1);
1721 tcpip_fillheaders(inp, ip6, th);
1722 } else
1723#endif
1724 {
1725 hdrlen = sizeof(struct tcpiphdr);
1726 ip = mtod(m, struct ip *);
1727 th = (struct tcphdr *)(ip + 1);
1728 tcpip_fillheaders(inp, ip, th);
1729 }
1730 optp = (u_int8_t *)(th + 1);
1731
1732 /*
1733 * Send a timestamp and echo-reply if both our side and our peer
1734 * have sent timestamps in our SYN's and this is not a RST.
1735 */
1736 if (tw->t_recent && flags == TH_ACK) {
1737 u_int32_t *lp = (u_int32_t *)optp;
1738
1739 /* Form timestamp option as shown in appendix A of RFC 1323. */
1740 *lp++ = htonl(TCPOPT_TSTAMP_HDR);
1741 *lp++ = htonl(ticks);
1742 *lp = htonl(tw->t_recent);
1743 optp += TCPOLEN_TSTAMP_APPA;
1744 }
1745
1746 /*
1747 * Send `CC-family' options if needed, and it's not a RST.
1748 */
1749 if (tw->cc_recv != 0 && flags == TH_ACK) {
1750 u_int32_t *lp = (u_int32_t *)optp;
1751
1752 *lp++ = htonl(TCPOPT_CC_HDR(TCPOPT_CC));
1753 *lp = htonl(tw->cc_send);
1754 optp += TCPOLEN_CC_APPA;
1755 }
1756 optlen = optp - (u_int8_t *)(th + 1);
1757
1758 m->m_len = hdrlen + optlen;
1759 m->m_pkthdr.len = m->m_len;
1760
1761 KASSERT(max_linkhdr + m->m_len <= MHLEN, ("tcptw: mbuf too small"));
1762
1763 th->th_seq = htonl(tw->snd_nxt);
1764 th->th_ack = htonl(tw->rcv_nxt);
1765 th->th_off = (sizeof(struct tcphdr) + optlen) >> 2;
1766 th->th_flags = flags;
1767 th->th_win = htons(tw->last_win);
1768
1769#ifdef INET6
1770 if (isipv6) {
1771 th->th_sum = in6_cksum(m, IPPROTO_TCP, sizeof(struct ip6_hdr),
1772 sizeof(struct tcphdr) + optlen);
1773 ip6->ip6_hlim = in6_selecthlim(inp, inp->in6p_route.ro_rt ?
1774 inp->in6p_route.ro_rt->rt_ifp : NULL);
1775 error = ip6_output(m, inp->in6p_outputopts, &inp->in6p_route,
1776 (tw->tw_so_options & SO_DONTROUTE), NULL, NULL, inp);
1777 } else
1778#endif
1779 {
1780 th->th_sum = in_pseudo(ip->ip_src.s_addr, ip->ip_dst.s_addr,
1781 htons(sizeof(struct tcphdr) + optlen + IPPROTO_TCP));
1782 m->m_pkthdr.csum_flags = CSUM_TCP;
1783 m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum);
1784 ip->ip_len = m->m_pkthdr.len;
1785 error = ip_output(m, inp->inp_options, &inp->inp_route,
1786 (tw->tw_so_options & SO_DONTROUTE), NULL, inp);
1787 }
1788 if (flags & TH_ACK)
1789 tcpstat.tcps_sndacks++;
1790 else
1791 tcpstat.tcps_sndctrl++;
1792 tcpstat.tcps_sndtotal++;
1793 return (error);
1794}
1795
1796/*
1797 * TCP BANDWIDTH DELAY PRODUCT WINDOW LIMITING
1798 *
1799 * This code attempts to calculate the bandwidth-delay product as a
1800 * means of determining the optimal window size to maximize bandwidth,
1801 * minimize RTT, and avoid the over-allocation of buffers on interfaces and
1802 * routers. This code also does a fairly good job keeping RTTs in check
1803 * across slow links like modems. We implement an algorithm which is very
1804 * similar (but not meant to be) TCP/Vegas. The code operates on the
1805 * transmitter side of a TCP connection and so only effects the transmit
1806 * side of the connection.
1807 *
1808 * BACKGROUND: TCP makes no provision for the management of buffer space
1809 * at the end points or at the intermediate routers and switches. A TCP
1810 * stream, whether using NewReno or not, will eventually buffer as
1811 * many packets as it is able and the only reason this typically works is
1812 * due to the fairly small default buffers made available for a connection
1813 * (typicaly 16K or 32K). As machines use larger windows and/or window
1814 * scaling it is now fairly easy for even a single TCP connection to blow-out
1815 * all available buffer space not only on the local interface, but on
1816 * intermediate routers and switches as well. NewReno makes a misguided
1817 * attempt to 'solve' this problem by waiting for an actual failure to occur,
1818 * then backing off, then steadily increasing the window again until another
1819 * failure occurs, ad-infinitum. This results in terrible oscillation that
1820 * is only made worse as network loads increase and the idea of intentionally
1821 * blowing out network buffers is, frankly, a terrible way to manage network
1822 * resources.
1823 *
1824 * It is far better to limit the transmit window prior to the failure
1825 * condition being achieved. There are two general ways to do this: First
1826 * you can 'scan' through different transmit window sizes and locate the
1827 * point where the RTT stops increasing, indicating that you have filled the
1828 * pipe, then scan backwards until you note that RTT stops decreasing, then
1829 * repeat ad-infinitum. This method works in principle but has severe
1830 * implementation issues due to RTT variances, timer granularity, and
1831 * instability in the algorithm which can lead to many false positives and
1832 * create oscillations as well as interact badly with other TCP streams
1833 * implementing the same algorithm.
1834 *
1835 * The second method is to limit the window to the bandwidth delay product
1836 * of the link. This is the method we implement. RTT variances and our
1837 * own manipulation of the congestion window, bwnd, can potentially
1838 * destabilize the algorithm. For this reason we have to stabilize the
1839 * elements used to calculate the window. We do this by using the minimum
1840 * observed RTT, the long term average of the observed bandwidth, and
1841 * by adding two segments worth of slop. It isn't perfect but it is able
1842 * to react to changing conditions and gives us a very stable basis on
1843 * which to extend the algorithm.
1844 */
1845void
1846tcp_xmit_bandwidth_limit(struct tcpcb *tp, tcp_seq ack_seq)
1847{
1848 u_long bw;
1849 u_long bwnd;
1850 int save_ticks;
1851
1852 /*
1853 * If inflight_enable is disabled in the middle of a tcp connection,
1854 * make sure snd_bwnd is effectively disabled.
1855 */
1856 if (tcp_inflight_enable == 0) {
1857 tp->snd_bwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT;
1858 tp->snd_bandwidth = 0;
1859 return;
1860 }
1861
1862 /*
1863 * Figure out the bandwidth. Due to the tick granularity this
1864 * is a very rough number and it MUST be averaged over a fairly
1865 * long period of time. XXX we need to take into account a link
1866 * that is not using all available bandwidth, but for now our
1867 * slop will ramp us up if this case occurs and the bandwidth later
1868 * increases.
1869 *
1870 * Note: if ticks rollover 'bw' may wind up negative. We must
1871 * effectively reset t_bw_rtttime for this case.
1872 */
1873 save_ticks = ticks;
1874 if ((u_int)(save_ticks - tp->t_bw_rtttime) < 1)
1875 return;
1876
1877 bw = (int64_t)(ack_seq - tp->t_bw_rtseq) * hz /
1878 (save_ticks - tp->t_bw_rtttime);
1879 tp->t_bw_rtttime = save_ticks;
1880 tp->t_bw_rtseq = ack_seq;
1881 if (tp->t_bw_rtttime == 0 || (int)bw < 0)
1882 return;
1883 bw = ((int64_t)tp->snd_bandwidth * 15 + bw) >> 4;
1884
1885 tp->snd_bandwidth = bw;
1886
1887 /*
1888 * Calculate the semi-static bandwidth delay product, plus two maximal
1889 * segments. The additional slop puts us squarely in the sweet
1890 * spot and also handles the bandwidth run-up case and stabilization.
1891 * Without the slop we could be locking ourselves into a lower
1892 * bandwidth.
1893 *
1894 * Situations Handled:
1895 * (1) Prevents over-queueing of packets on LANs, especially on
1896 * high speed LANs, allowing larger TCP buffers to be
1897 * specified, and also does a good job preventing
1898 * over-queueing of packets over choke points like modems
1899 * (at least for the transmit side).
1900 *
1901 * (2) Is able to handle changing network loads (bandwidth
1902 * drops so bwnd drops, bandwidth increases so bwnd
1903 * increases).
1904 *
1905 * (3) Theoretically should stabilize in the face of multiple
1906 * connections implementing the same algorithm (this may need
1907 * a little work).
1908 *
1909 * (4) Stability value (defaults to 20 = 2 maximal packets) can
1910 * be adjusted with a sysctl but typically only needs to be
1911 * on very slow connections. A value no smaller then 5
1912 * should be used, but only reduce this default if you have
1913 * no other choice.
1914 */
1915#define USERTT ((tp->t_srtt + tp->t_rttbest) / 2)
1916 bwnd = (int64_t)bw * USERTT / (hz << TCP_RTT_SHIFT) + tcp_inflight_stab * tp->t_maxseg / 10;
1917#undef USERTT
1918
1919 if (tcp_inflight_debug > 0) {
1920 static int ltime;
1921 if ((u_int)(ticks - ltime) >= hz / tcp_inflight_debug) {
1922 ltime = ticks;
1923 printf("%p bw %ld rttbest %d srtt %d bwnd %ld\n",
1924 tp,
1925 bw,
1926 tp->t_rttbest,
1927 tp->t_srtt,
1928 bwnd
1929 );
1930 }
1931 }
1932 if ((long)bwnd < tcp_inflight_min)
1933 bwnd = tcp_inflight_min;
1934 if (bwnd > tcp_inflight_max)
1935 bwnd = tcp_inflight_max;
1936 if ((long)bwnd < tp->t_maxseg * 2)
1937 bwnd = tp->t_maxseg * 2;
1938 tp->snd_bwnd = bwnd;
1939}
1940
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