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 * 4. Neither the name of the University nor the names of its contributors
14 * may be used to endorse or promote products derived from this software
15 * without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 *
29 * @(#)tcp_subr.c 8.2 (Berkeley) 5/24/95
30 */
31
32 #include <sys/cdefs.h>
33 __FBSDID("$FreeBSD: releng/9.1/sys/netinet/tcp_subr.c 238247 2012-07-08 14:21:36Z bz $");
34
35 #include "opt_compat.h"
36 #include "opt_inet.h"
37 #include "opt_inet6.h"
38 #include "opt_ipsec.h"
39 #include "opt_tcpdebug.h"
40
41 #include <sys/param.h>
42 #include <sys/systm.h>
43 #include <sys/callout.h>
44 #include <sys/hhook.h>
45 #include <sys/kernel.h>
46 #include <sys/khelp.h>
47 #include <sys/sysctl.h>
48 #include <sys/jail.h>
49 #include <sys/malloc.h>
50 #include <sys/mbuf.h>
51 #ifdef INET6
52 #include <sys/domain.h>
53 #endif
54 #include <sys/priv.h>
55 #include <sys/proc.h>
56 #include <sys/socket.h>
57 #include <sys/socketvar.h>
58 #include <sys/protosw.h>
59 #include <sys/random.h>
60
61 #include <vm/uma.h>
62
63 #include <net/route.h>
64 #include <net/if.h>
65 #include <net/vnet.h>
66
67 #include <netinet/cc.h>
68 #include <netinet/in.h>
69 #include <netinet/in_pcb.h>
70 #include <netinet/in_systm.h>
71 #include <netinet/in_var.h>
72 #include <netinet/ip.h>
73 #include <netinet/ip_icmp.h>
74 #include <netinet/ip_var.h>
75 #ifdef INET6
76 #include <netinet/ip6.h>
77 #include <netinet6/in6_pcb.h>
78 #include <netinet6/ip6_var.h>
79 #include <netinet6/scope6_var.h>
80 #include <netinet6/nd6.h>
81 #endif
82
83 #include <netinet/tcp_fsm.h>
84 #include <netinet/tcp_seq.h>
85 #include <netinet/tcp_timer.h>
86 #include <netinet/tcp_var.h>
87 #include <netinet/tcp_syncache.h>
88 #include <netinet/tcp_offload.h>
89 #ifdef INET6
90 #include <netinet6/tcp6_var.h>
91 #endif
92 #include <netinet/tcpip.h>
93 #ifdef TCPDEBUG
94 #include <netinet/tcp_debug.h>
95 #endif
96 #ifdef INET6
97 #include <netinet6/ip6protosw.h>
98 #endif
99
100 #ifdef IPSEC
101 #include <netipsec/ipsec.h>
102 #include <netipsec/xform.h>
103 #ifdef INET6
104 #include <netipsec/ipsec6.h>
105 #endif
106 #include <netipsec/key.h>
107 #include <sys/syslog.h>
108 #endif /*IPSEC*/
109
110 #include <machine/in_cksum.h>
111 #include <sys/md5.h>
112
113 #include <security/mac/mac_framework.h>
114
115 VNET_DEFINE(int, tcp_mssdflt) = TCP_MSS;
116 #ifdef INET6
117 VNET_DEFINE(int, tcp_v6mssdflt) = TCP6_MSS;
118 #endif
119
120 static int
121 sysctl_net_inet_tcp_mss_check(SYSCTL_HANDLER_ARGS)
122 {
123 int error, new;
124
125 new = V_tcp_mssdflt;
126 error = sysctl_handle_int(oidp, &new, 0, req);
127 if (error == 0 && req->newptr) {
128 if (new < TCP_MINMSS)
129 error = EINVAL;
130 else
131 V_tcp_mssdflt = new;
132 }
133 return (error);
134 }
135
136 SYSCTL_VNET_PROC(_net_inet_tcp, TCPCTL_MSSDFLT, mssdflt,
137 CTLTYPE_INT|CTLFLAG_RW, &VNET_NAME(tcp_mssdflt), 0,
138 &sysctl_net_inet_tcp_mss_check, "I",
139 "Default TCP Maximum Segment Size");
140
141 #ifdef INET6
142 static int
143 sysctl_net_inet_tcp_mss_v6_check(SYSCTL_HANDLER_ARGS)
144 {
145 int error, new;
146
147 new = V_tcp_v6mssdflt;
148 error = sysctl_handle_int(oidp, &new, 0, req);
149 if (error == 0 && req->newptr) {
150 if (new < TCP_MINMSS)
151 error = EINVAL;
152 else
153 V_tcp_v6mssdflt = new;
154 }
155 return (error);
156 }
157
158 SYSCTL_VNET_PROC(_net_inet_tcp, TCPCTL_V6MSSDFLT, v6mssdflt,
159 CTLTYPE_INT|CTLFLAG_RW, &VNET_NAME(tcp_v6mssdflt), 0,
160 &sysctl_net_inet_tcp_mss_v6_check, "I",
161 "Default TCP Maximum Segment Size for IPv6");
162 #endif /* INET6 */
163
164 /*
165 * Minimum MSS we accept and use. This prevents DoS attacks where
166 * we are forced to a ridiculous low MSS like 20 and send hundreds
167 * of packets instead of one. The effect scales with the available
168 * bandwidth and quickly saturates the CPU and network interface
169 * with packet generation and sending. Set to zero to disable MINMSS
170 * checking. This setting prevents us from sending too small packets.
171 */
172 VNET_DEFINE(int, tcp_minmss) = TCP_MINMSS;
173 SYSCTL_VNET_INT(_net_inet_tcp, OID_AUTO, minmss, CTLFLAG_RW,
174 &VNET_NAME(tcp_minmss), 0,
175 "Minmum TCP Maximum Segment Size");
176
177 VNET_DEFINE(int, tcp_do_rfc1323) = 1;
178 SYSCTL_VNET_INT(_net_inet_tcp, TCPCTL_DO_RFC1323, rfc1323, CTLFLAG_RW,
179 &VNET_NAME(tcp_do_rfc1323), 0,
180 "Enable rfc1323 (high performance TCP) extensions");
181
182 static int tcp_log_debug = 0;
183 SYSCTL_INT(_net_inet_tcp, OID_AUTO, log_debug, CTLFLAG_RW,
184 &tcp_log_debug, 0, "Log errors caused by incoming TCP segments");
185
186 static int tcp_tcbhashsize = 0;
187 SYSCTL_INT(_net_inet_tcp, OID_AUTO, tcbhashsize, CTLFLAG_RDTUN,
188 &tcp_tcbhashsize, 0, "Size of TCP control-block hashtable");
189
190 static int do_tcpdrain = 1;
191 SYSCTL_INT(_net_inet_tcp, OID_AUTO, do_tcpdrain, CTLFLAG_RW, &do_tcpdrain, 0,
192 "Enable tcp_drain routine for extra help when low on mbufs");
193
194 SYSCTL_VNET_UINT(_net_inet_tcp, OID_AUTO, pcbcount, CTLFLAG_RD,
195 &VNET_NAME(tcbinfo.ipi_count), 0, "Number of active PCBs");
196
197 static VNET_DEFINE(int, icmp_may_rst) = 1;
198 #define V_icmp_may_rst VNET(icmp_may_rst)
199 SYSCTL_VNET_INT(_net_inet_tcp, OID_AUTO, icmp_may_rst, CTLFLAG_RW,
200 &VNET_NAME(icmp_may_rst), 0,
201 "Certain ICMP unreachable messages may abort connections in SYN_SENT");
202
203 static VNET_DEFINE(int, tcp_isn_reseed_interval) = 0;
204 #define V_tcp_isn_reseed_interval VNET(tcp_isn_reseed_interval)
205 SYSCTL_VNET_INT(_net_inet_tcp, OID_AUTO, isn_reseed_interval, CTLFLAG_RW,
206 &VNET_NAME(tcp_isn_reseed_interval), 0,
207 "Seconds between reseeding of ISN secret");
208
209 static int tcp_soreceive_stream = 0;
210 SYSCTL_INT(_net_inet_tcp, OID_AUTO, soreceive_stream, CTLFLAG_RDTUN,
211 &tcp_soreceive_stream, 0, "Using soreceive_stream for TCP sockets");
212
213 #ifdef TCP_SIGNATURE
214 static int tcp_sig_checksigs = 1;
215 SYSCTL_INT(_net_inet_tcp, OID_AUTO, signature_verify_input, CTLFLAG_RW,
216 &tcp_sig_checksigs, 0, "Verify RFC2385 digests on inbound traffic");
217 #endif
218
219 VNET_DEFINE(uma_zone_t, sack_hole_zone);
220 #define V_sack_hole_zone VNET(sack_hole_zone)
221
222 VNET_DEFINE(struct hhook_head *, tcp_hhh[HHOOK_TCP_LAST+1]);
223
224 static struct inpcb *tcp_notify(struct inpcb *, int);
225 static struct inpcb *tcp_mtudisc_notify(struct inpcb *, int);
226 static char * tcp_log_addr(struct in_conninfo *inc, struct tcphdr *th,
227 void *ip4hdr, const void *ip6hdr);
228
229 /*
230 * Target size of TCP PCB hash tables. Must be a power of two.
231 *
232 * Note that this can be overridden by the kernel environment
233 * variable net.inet.tcp.tcbhashsize
234 */
235 #ifndef TCBHASHSIZE
236 #define TCBHASHSIZE 512
237 #endif
238
239 /*
240 * XXX
241 * Callouts should be moved into struct tcp directly. They are currently
242 * separate because the tcpcb structure is exported to userland for sysctl
243 * parsing purposes, which do not know about callouts.
244 */
245 struct tcpcb_mem {
246 struct tcpcb tcb;
247 struct tcp_timer tt;
248 struct cc_var ccv;
249 struct osd osd;
250 };
251
252 static VNET_DEFINE(uma_zone_t, tcpcb_zone);
253 #define V_tcpcb_zone VNET(tcpcb_zone)
254
255 MALLOC_DEFINE(M_TCPLOG, "tcplog", "TCP address and flags print buffers");
256 static struct mtx isn_mtx;
257
258 #define ISN_LOCK_INIT() mtx_init(&isn_mtx, "isn_mtx", NULL, MTX_DEF)
259 #define ISN_LOCK() mtx_lock(&isn_mtx)
260 #define ISN_UNLOCK() mtx_unlock(&isn_mtx)
261
262 /*
263 * TCP initialization.
264 */
265 static void
266 tcp_zone_change(void *tag)
267 {
268
269 uma_zone_set_max(V_tcbinfo.ipi_zone, maxsockets);
270 uma_zone_set_max(V_tcpcb_zone, maxsockets);
271 tcp_tw_zone_change();
272 }
273
274 static int
275 tcp_inpcb_init(void *mem, int size, int flags)
276 {
277 struct inpcb *inp = mem;
278
279 INP_LOCK_INIT(inp, "inp", "tcpinp");
280 return (0);
281 }
282
283 void
284 tcp_init(void)
285 {
286 int hashsize;
287
288 if (hhook_head_register(HHOOK_TYPE_TCP, HHOOK_TCP_EST_IN,
289 &V_tcp_hhh[HHOOK_TCP_EST_IN], HHOOK_NOWAIT|HHOOK_HEADISINVNET) != 0)
290 printf("%s: WARNING: unable to register helper hook\n", __func__);
291 if (hhook_head_register(HHOOK_TYPE_TCP, HHOOK_TCP_EST_OUT,
292 &V_tcp_hhh[HHOOK_TCP_EST_OUT], HHOOK_NOWAIT|HHOOK_HEADISINVNET) != 0)
293 printf("%s: WARNING: unable to register helper hook\n", __func__);
294
295 hashsize = TCBHASHSIZE;
296 TUNABLE_INT_FETCH("net.inet.tcp.tcbhashsize", &hashsize);
297 if (!powerof2(hashsize)) {
298 printf("WARNING: TCB hash size not a power of 2\n");
299 hashsize = 512; /* safe default */
300 }
301 in_pcbinfo_init(&V_tcbinfo, "tcp", &V_tcb, hashsize, hashsize,
302 "tcp_inpcb", tcp_inpcb_init, NULL, UMA_ZONE_NOFREE,
303 IPI_HASHFIELDS_4TUPLE);
304
305 /*
306 * These have to be type stable for the benefit of the timers.
307 */
308 V_tcpcb_zone = uma_zcreate("tcpcb", sizeof(struct tcpcb_mem),
309 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE);
310 uma_zone_set_max(V_tcpcb_zone, maxsockets);
311
312 tcp_tw_init();
313 syncache_init();
314 tcp_hc_init();
315 tcp_reass_init();
316
317 TUNABLE_INT_FETCH("net.inet.tcp.sack.enable", &V_tcp_do_sack);
318 V_sack_hole_zone = uma_zcreate("sackhole", sizeof(struct sackhole),
319 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE);
320
321 /* Skip initialization of globals for non-default instances. */
322 if (!IS_DEFAULT_VNET(curvnet))
323 return;
324
325 /* XXX virtualize those bellow? */
326 tcp_delacktime = TCPTV_DELACK;
327 tcp_keepinit = TCPTV_KEEP_INIT;
328 tcp_keepidle = TCPTV_KEEP_IDLE;
329 tcp_keepintvl = TCPTV_KEEPINTVL;
330 tcp_maxpersistidle = TCPTV_KEEP_IDLE;
331 tcp_msl = TCPTV_MSL;
332 tcp_rexmit_min = TCPTV_MIN;
333 if (tcp_rexmit_min < 1)
334 tcp_rexmit_min = 1;
335 tcp_rexmit_slop = TCPTV_CPU_VAR;
336 tcp_finwait2_timeout = TCPTV_FINWAIT2_TIMEOUT;
337 tcp_tcbhashsize = hashsize;
338
339 TUNABLE_INT_FETCH("net.inet.tcp.soreceive_stream", &tcp_soreceive_stream);
340 if (tcp_soreceive_stream) {
341 #ifdef INET
342 tcp_usrreqs.pru_soreceive = soreceive_stream;
343 #endif
344 #ifdef INET6
345 tcp6_usrreqs.pru_soreceive = soreceive_stream;
346 #endif /* INET6 */
347 }
348
349 #ifdef INET6
350 #define TCP_MINPROTOHDR (sizeof(struct ip6_hdr) + sizeof(struct tcphdr))
351 #else /* INET6 */
352 #define TCP_MINPROTOHDR (sizeof(struct tcpiphdr))
353 #endif /* INET6 */
354 if (max_protohdr < TCP_MINPROTOHDR)
355 max_protohdr = TCP_MINPROTOHDR;
356 if (max_linkhdr + TCP_MINPROTOHDR > MHLEN)
357 panic("tcp_init");
358 #undef TCP_MINPROTOHDR
359
360 ISN_LOCK_INIT();
361 EVENTHANDLER_REGISTER(shutdown_pre_sync, tcp_fini, NULL,
362 SHUTDOWN_PRI_DEFAULT);
363 EVENTHANDLER_REGISTER(maxsockets_change, tcp_zone_change, NULL,
364 EVENTHANDLER_PRI_ANY);
365 }
366
367 #ifdef VIMAGE
368 void
369 tcp_destroy(void)
370 {
371
372 tcp_reass_destroy();
373 tcp_hc_destroy();
374 syncache_destroy();
375 tcp_tw_destroy();
376 in_pcbinfo_destroy(&V_tcbinfo);
377 uma_zdestroy(V_sack_hole_zone);
378 uma_zdestroy(V_tcpcb_zone);
379 }
380 #endif
381
382 void
383 tcp_fini(void *xtp)
384 {
385
386 }
387
388 /*
389 * Fill in the IP and TCP headers for an outgoing packet, given the tcpcb.
390 * tcp_template used to store this data in mbufs, but we now recopy it out
391 * of the tcpcb each time to conserve mbufs.
392 */
393 void
394 tcpip_fillheaders(struct inpcb *inp, void *ip_ptr, void *tcp_ptr)
395 {
396 struct tcphdr *th = (struct tcphdr *)tcp_ptr;
397
398 INP_WLOCK_ASSERT(inp);
399
400 #ifdef INET6
401 if ((inp->inp_vflag & INP_IPV6) != 0) {
402 struct ip6_hdr *ip6;
403
404 ip6 = (struct ip6_hdr *)ip_ptr;
405 ip6->ip6_flow = (ip6->ip6_flow & ~IPV6_FLOWINFO_MASK) |
406 (inp->inp_flow & IPV6_FLOWINFO_MASK);
407 ip6->ip6_vfc = (ip6->ip6_vfc & ~IPV6_VERSION_MASK) |
408 (IPV6_VERSION & IPV6_VERSION_MASK);
409 ip6->ip6_nxt = IPPROTO_TCP;
410 ip6->ip6_plen = htons(sizeof(struct tcphdr));
411 ip6->ip6_src = inp->in6p_laddr;
412 ip6->ip6_dst = inp->in6p_faddr;
413 }
414 #endif /* INET6 */
415 #if defined(INET6) && defined(INET)
416 else
417 #endif
418 #ifdef INET
419 {
420 struct ip *ip;
421
422 ip = (struct ip *)ip_ptr;
423 ip->ip_v = IPVERSION;
424 ip->ip_hl = 5;
425 ip->ip_tos = inp->inp_ip_tos;
426 ip->ip_len = 0;
427 ip->ip_id = 0;
428 ip->ip_off = 0;
429 ip->ip_ttl = inp->inp_ip_ttl;
430 ip->ip_sum = 0;
431 ip->ip_p = IPPROTO_TCP;
432 ip->ip_src = inp->inp_laddr;
433 ip->ip_dst = inp->inp_faddr;
434 }
435 #endif /* INET */
436 th->th_sport = inp->inp_lport;
437 th->th_dport = inp->inp_fport;
438 th->th_seq = 0;
439 th->th_ack = 0;
440 th->th_x2 = 0;
441 th->th_off = 5;
442 th->th_flags = 0;
443 th->th_win = 0;
444 th->th_urp = 0;
445 th->th_sum = 0; /* in_pseudo() is called later for ipv4 */
446 }
447
448 /*
449 * Create template to be used to send tcp packets on a connection.
450 * Allocates an mbuf and fills in a skeletal tcp/ip header. The only
451 * use for this function is in keepalives, which use tcp_respond.
452 */
453 struct tcptemp *
454 tcpip_maketemplate(struct inpcb *inp)
455 {
456 struct tcptemp *t;
457
458 t = malloc(sizeof(*t), M_TEMP, M_NOWAIT);
459 if (t == NULL)
460 return (NULL);
461 tcpip_fillheaders(inp, (void *)&t->tt_ipgen, (void *)&t->tt_t);
462 return (t);
463 }
464
465 /*
466 * Send a single message to the TCP at address specified by
467 * the given TCP/IP header. If m == NULL, then we make a copy
468 * of the tcpiphdr at ti and send directly to the addressed host.
469 * This is used to force keep alive messages out using the TCP
470 * template for a connection. If flags are given then we send
471 * a message back to the TCP which originated the * segment ti,
472 * and discard the mbuf containing it and any other attached mbufs.
473 *
474 * In any case the ack and sequence number of the transmitted
475 * segment are as specified by the parameters.
476 *
477 * NOTE: If m != NULL, then ti must point to *inside* the mbuf.
478 */
479 void
480 tcp_respond(struct tcpcb *tp, void *ipgen, struct tcphdr *th, struct mbuf *m,
481 tcp_seq ack, tcp_seq seq, int flags)
482 {
483 int tlen;
484 int win = 0;
485 struct ip *ip;
486 struct tcphdr *nth;
487 #ifdef INET6
488 struct ip6_hdr *ip6;
489 int isipv6;
490 #endif /* INET6 */
491 int ipflags = 0;
492 struct inpcb *inp;
493
494 KASSERT(tp != NULL || m != NULL, ("tcp_respond: tp and m both NULL"));
495
496 #ifdef INET6
497 isipv6 = ((struct ip *)ipgen)->ip_v == (IPV6_VERSION >> 4);
498 ip6 = ipgen;
499 #endif /* INET6 */
500 ip = ipgen;
501
502 if (tp != NULL) {
503 inp = tp->t_inpcb;
504 KASSERT(inp != NULL, ("tcp control block w/o inpcb"));
505 INP_WLOCK_ASSERT(inp);
506 } else
507 inp = NULL;
508
509 if (tp != NULL) {
510 if (!(flags & TH_RST)) {
511 win = sbspace(&inp->inp_socket->so_rcv);
512 if (win > (long)TCP_MAXWIN << tp->rcv_scale)
513 win = (long)TCP_MAXWIN << tp->rcv_scale;
514 }
515 }
516 if (m == NULL) {
517 m = m_gethdr(M_DONTWAIT, MT_DATA);
518 if (m == NULL)
519 return;
520 tlen = 0;
521 m->m_data += max_linkhdr;
522 #ifdef INET6
523 if (isipv6) {
524 bcopy((caddr_t)ip6, mtod(m, caddr_t),
525 sizeof(struct ip6_hdr));
526 ip6 = mtod(m, struct ip6_hdr *);
527 nth = (struct tcphdr *)(ip6 + 1);
528 } else
529 #endif /* INET6 */
530 {
531 bcopy((caddr_t)ip, mtod(m, caddr_t), sizeof(struct ip));
532 ip = mtod(m, struct ip *);
533 nth = (struct tcphdr *)(ip + 1);
534 }
535 bcopy((caddr_t)th, (caddr_t)nth, sizeof(struct tcphdr));
536 flags = TH_ACK;
537 } else {
538 /*
539 * reuse the mbuf.
540 * XXX MRT We inherrit the FIB, which is lucky.
541 */
542 m_freem(m->m_next);
543 m->m_next = NULL;
544 m->m_data = (caddr_t)ipgen;
545 m_addr_changed(m);
546 /* m_len is set later */
547 tlen = 0;
548 #define xchg(a,b,type) { type t; t=a; a=b; b=t; }
549 #ifdef INET6
550 if (isipv6) {
551 xchg(ip6->ip6_dst, ip6->ip6_src, struct in6_addr);
552 nth = (struct tcphdr *)(ip6 + 1);
553 } else
554 #endif /* INET6 */
555 {
556 xchg(ip->ip_dst.s_addr, ip->ip_src.s_addr, uint32_t);
557 nth = (struct tcphdr *)(ip + 1);
558 }
559 if (th != nth) {
560 /*
561 * this is usually a case when an extension header
562 * exists between the IPv6 header and the
563 * TCP header.
564 */
565 nth->th_sport = th->th_sport;
566 nth->th_dport = th->th_dport;
567 }
568 xchg(nth->th_dport, nth->th_sport, uint16_t);
569 #undef xchg
570 }
571 #ifdef INET6
572 if (isipv6) {
573 ip6->ip6_flow = 0;
574 ip6->ip6_vfc = IPV6_VERSION;
575 ip6->ip6_nxt = IPPROTO_TCP;
576 ip6->ip6_plen = 0; /* Set in ip6_output(). */
577 tlen += sizeof (struct ip6_hdr) + sizeof (struct tcphdr);
578 }
579 #endif
580 #if defined(INET) && defined(INET6)
581 else
582 #endif
583 #ifdef INET
584 {
585 tlen += sizeof (struct tcpiphdr);
586 ip->ip_len = tlen;
587 ip->ip_ttl = V_ip_defttl;
588 if (V_path_mtu_discovery)
589 ip->ip_off |= IP_DF;
590 }
591 #endif
592 m->m_len = tlen;
593 m->m_pkthdr.len = tlen;
594 m->m_pkthdr.rcvif = NULL;
595 #ifdef MAC
596 if (inp != NULL) {
597 /*
598 * Packet is associated with a socket, so allow the
599 * label of the response to reflect the socket label.
600 */
601 INP_WLOCK_ASSERT(inp);
602 mac_inpcb_create_mbuf(inp, m);
603 } else {
604 /*
605 * Packet is not associated with a socket, so possibly
606 * update the label in place.
607 */
608 mac_netinet_tcp_reply(m);
609 }
610 #endif
611 nth->th_seq = htonl(seq);
612 nth->th_ack = htonl(ack);
613 nth->th_x2 = 0;
614 nth->th_off = sizeof (struct tcphdr) >> 2;
615 nth->th_flags = flags;
616 if (tp != NULL)
617 nth->th_win = htons((u_short) (win >> tp->rcv_scale));
618 else
619 nth->th_win = htons((u_short)win);
620 nth->th_urp = 0;
621
622 m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum);
623 #ifdef INET6
624 if (isipv6) {
625 m->m_pkthdr.csum_flags = CSUM_TCP_IPV6;
626 nth->th_sum = in6_cksum_pseudo(ip6,
627 tlen - sizeof(struct ip6_hdr), IPPROTO_TCP, 0);
628 ip6->ip6_hlim = in6_selecthlim(tp != NULL ? tp->t_inpcb :
629 NULL, NULL);
630 }
631 #endif /* INET6 */
632 #if defined(INET6) && defined(INET)
633 else
634 #endif
635 #ifdef INET
636 {
637 m->m_pkthdr.csum_flags = CSUM_TCP;
638 nth->th_sum = in_pseudo(ip->ip_src.s_addr, ip->ip_dst.s_addr,
639 htons((u_short)(tlen - sizeof(struct ip) + ip->ip_p)));
640 }
641 #endif /* INET */
642 #ifdef TCPDEBUG
643 if (tp == NULL || (inp->inp_socket->so_options & SO_DEBUG))
644 tcp_trace(TA_OUTPUT, 0, tp, mtod(m, void *), th, 0);
645 #endif
646 #ifdef INET6
647 if (isipv6)
648 (void) ip6_output(m, NULL, NULL, ipflags, NULL, NULL, inp);
649 #endif /* INET6 */
650 #if defined(INET) && defined(INET6)
651 else
652 #endif
653 #ifdef INET
654 (void) ip_output(m, NULL, NULL, ipflags, NULL, inp);
655 #endif
656 }
657
658 /*
659 * Create a new TCP control block, making an
660 * empty reassembly queue and hooking it to the argument
661 * protocol control block. The `inp' parameter must have
662 * come from the zone allocator set up in tcp_init().
663 */
664 struct tcpcb *
665 tcp_newtcpcb(struct inpcb *inp)
666 {
667 struct tcpcb_mem *tm;
668 struct tcpcb *tp;
669 #ifdef INET6
670 int isipv6 = (inp->inp_vflag & INP_IPV6) != 0;
671 #endif /* INET6 */
672
673 tm = uma_zalloc(V_tcpcb_zone, M_NOWAIT | M_ZERO);
674 if (tm == NULL)
675 return (NULL);
676 tp = &tm->tcb;
677
678 /* Initialise cc_var struct for this tcpcb. */
679 tp->ccv = &tm->ccv;
680 tp->ccv->type = IPPROTO_TCP;
681 tp->ccv->ccvc.tcp = tp;
682
683 /*
684 * Use the current system default CC algorithm.
685 */
686 CC_LIST_RLOCK();
687 KASSERT(!STAILQ_EMPTY(&cc_list), ("cc_list is empty!"));
688 CC_ALGO(tp) = CC_DEFAULT();
689 CC_LIST_RUNLOCK();
690
691 if (CC_ALGO(tp)->cb_init != NULL)
692 if (CC_ALGO(tp)->cb_init(tp->ccv) > 0) {
693 uma_zfree(V_tcpcb_zone, tm);
694 return (NULL);
695 }
696
697 tp->osd = &tm->osd;
698 if (khelp_init_osd(HELPER_CLASS_TCP, tp->osd)) {
699 uma_zfree(V_tcpcb_zone, tm);
700 return (NULL);
701 }
702
703 #ifdef VIMAGE
704 tp->t_vnet = inp->inp_vnet;
705 #endif
706 tp->t_timers = &tm->tt;
707 /* LIST_INIT(&tp->t_segq); */ /* XXX covered by M_ZERO */
708 tp->t_maxseg = tp->t_maxopd =
709 #ifdef INET6
710 isipv6 ? V_tcp_v6mssdflt :
711 #endif /* INET6 */
712 V_tcp_mssdflt;
713
714 /* Set up our timeouts. */
715 callout_init(&tp->t_timers->tt_rexmt, CALLOUT_MPSAFE);
716 callout_init(&tp->t_timers->tt_persist, CALLOUT_MPSAFE);
717 callout_init(&tp->t_timers->tt_keep, CALLOUT_MPSAFE);
718 callout_init(&tp->t_timers->tt_2msl, CALLOUT_MPSAFE);
719 callout_init(&tp->t_timers->tt_delack, CALLOUT_MPSAFE);
720
721 if (V_tcp_do_rfc1323)
722 tp->t_flags = (TF_REQ_SCALE|TF_REQ_TSTMP);
723 if (V_tcp_do_sack)
724 tp->t_flags |= TF_SACK_PERMIT;
725 TAILQ_INIT(&tp->snd_holes);
726 tp->t_inpcb = inp; /* XXX */
727 /*
728 * Init srtt to TCPTV_SRTTBASE (0), so we can tell that we have no
729 * rtt estimate. Set rttvar so that srtt + 4 * rttvar gives
730 * reasonable initial retransmit time.
731 */
732 tp->t_srtt = TCPTV_SRTTBASE;
733 tp->t_rttvar = ((TCPTV_RTOBASE - TCPTV_SRTTBASE) << TCP_RTTVAR_SHIFT) / 4;
734 tp->t_rttmin = tcp_rexmit_min;
735 tp->t_rxtcur = TCPTV_RTOBASE;
736 tp->snd_cwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT;
737 tp->snd_ssthresh = TCP_MAXWIN << TCP_MAX_WINSHIFT;
738 tp->t_rcvtime = ticks;
739 /*
740 * IPv4 TTL initialization is necessary for an IPv6 socket as well,
741 * because the socket may be bound to an IPv6 wildcard address,
742 * which may match an IPv4-mapped IPv6 address.
743 */
744 inp->inp_ip_ttl = V_ip_defttl;
745 inp->inp_ppcb = tp;
746 return (tp); /* XXX */
747 }
748
749 /*
750 * Switch the congestion control algorithm back to NewReno for any active
751 * control blocks using an algorithm which is about to go away.
752 * This ensures the CC framework can allow the unload to proceed without leaving
753 * any dangling pointers which would trigger a panic.
754 * Returning non-zero would inform the CC framework that something went wrong
755 * and it would be unsafe to allow the unload to proceed. However, there is no
756 * way for this to occur with this implementation so we always return zero.
757 */
758 int
759 tcp_ccalgounload(struct cc_algo *unload_algo)
760 {
761 struct cc_algo *tmpalgo;
762 struct inpcb *inp;
763 struct tcpcb *tp;
764 VNET_ITERATOR_DECL(vnet_iter);
765
766 /*
767 * Check all active control blocks across all network stacks and change
768 * any that are using "unload_algo" back to NewReno. If "unload_algo"
769 * requires cleanup code to be run, call it.
770 */
771 VNET_LIST_RLOCK();
772 VNET_FOREACH(vnet_iter) {
773 CURVNET_SET(vnet_iter);
774 INP_INFO_RLOCK(&V_tcbinfo);
775 /*
776 * New connections already part way through being initialised
777 * with the CC algo we're removing will not race with this code
778 * because the INP_INFO_WLOCK is held during initialisation. We
779 * therefore don't enter the loop below until the connection
780 * list has stabilised.
781 */
782 LIST_FOREACH(inp, &V_tcb, inp_list) {
783 INP_WLOCK(inp);
784 /* Important to skip tcptw structs. */
785 if (!(inp->inp_flags & INP_TIMEWAIT) &&
786 (tp = intotcpcb(inp)) != NULL) {
787 /*
788 * By holding INP_WLOCK here, we are assured
789 * that the connection is not currently
790 * executing inside the CC module's functions
791 * i.e. it is safe to make the switch back to
792 * NewReno.
793 */
794 if (CC_ALGO(tp) == unload_algo) {
795 tmpalgo = CC_ALGO(tp);
796 /* NewReno does not require any init. */
797 CC_ALGO(tp) = &newreno_cc_algo;
798 if (tmpalgo->cb_destroy != NULL)
799 tmpalgo->cb_destroy(tp->ccv);
800 }
801 }
802 INP_WUNLOCK(inp);
803 }
804 INP_INFO_RUNLOCK(&V_tcbinfo);
805 CURVNET_RESTORE();
806 }
807 VNET_LIST_RUNLOCK();
808
809 return (0);
810 }
811
812 /*
813 * Drop a TCP connection, reporting
814 * the specified error. If connection is synchronized,
815 * then send a RST to peer.
816 */
817 struct tcpcb *
818 tcp_drop(struct tcpcb *tp, int errno)
819 {
820 struct socket *so = tp->t_inpcb->inp_socket;
821
822 INP_INFO_WLOCK_ASSERT(&V_tcbinfo);
823 INP_WLOCK_ASSERT(tp->t_inpcb);
824
825 if (TCPS_HAVERCVDSYN(tp->t_state)) {
826 tp->t_state = TCPS_CLOSED;
827 (void) tcp_output_reset(tp);
828 TCPSTAT_INC(tcps_drops);
829 } else
830 TCPSTAT_INC(tcps_conndrops);
831 if (errno == ETIMEDOUT && tp->t_softerror)
832 errno = tp->t_softerror;
833 so->so_error = errno;
834 return (tcp_close(tp));
835 }
836
837 void
838 tcp_discardcb(struct tcpcb *tp)
839 {
840 struct inpcb *inp = tp->t_inpcb;
841 struct socket *so = inp->inp_socket;
842 #ifdef INET6
843 int isipv6 = (inp->inp_vflag & INP_IPV6) != 0;
844 #endif /* INET6 */
845
846 INP_WLOCK_ASSERT(inp);
847
848 /*
849 * Make sure that all of our timers are stopped before we delete the
850 * PCB.
851 *
852 * XXXRW: Really, we would like to use callout_drain() here in order
853 * to avoid races experienced in tcp_timer.c where a timer is already
854 * executing at this point. However, we can't, both because we're
855 * running in a context where we can't sleep, and also because we
856 * hold locks required by the timers. What we instead need to do is
857 * test to see if callout_drain() is required, and if so, defer some
858 * portion of the remainder of tcp_discardcb() to an asynchronous
859 * context that can callout_drain() and then continue. Some care
860 * will be required to ensure that no further processing takes place
861 * on the tcpcb, even though it hasn't been freed (a flag?).
862 */
863 callout_stop(&tp->t_timers->tt_rexmt);
864 callout_stop(&tp->t_timers->tt_persist);
865 callout_stop(&tp->t_timers->tt_keep);
866 callout_stop(&tp->t_timers->tt_2msl);
867 callout_stop(&tp->t_timers->tt_delack);
868
869 /*
870 * If we got enough samples through the srtt filter,
871 * save the rtt and rttvar in the routing entry.
872 * 'Enough' is arbitrarily defined as 4 rtt samples.
873 * 4 samples is enough for the srtt filter to converge
874 * to within enough % of the correct value; fewer samples
875 * and we could save a bogus rtt. The danger is not high
876 * as tcp quickly recovers from everything.
877 * XXX: Works very well but needs some more statistics!
878 */
879 if (tp->t_rttupdated >= 4) {
880 struct hc_metrics_lite metrics;
881 u_long ssthresh;
882
883 bzero(&metrics, sizeof(metrics));
884 /*
885 * Update the ssthresh always when the conditions below
886 * are satisfied. This gives us better new start value
887 * for the congestion avoidance for new connections.
888 * ssthresh is only set if packet loss occured on a session.
889 *
890 * XXXRW: 'so' may be NULL here, and/or socket buffer may be
891 * being torn down. Ideally this code would not use 'so'.
892 */
893 ssthresh = tp->snd_ssthresh;
894 if (ssthresh != 0 && ssthresh < so->so_snd.sb_hiwat / 2) {
895 /*
896 * convert the limit from user data bytes to
897 * packets then to packet data bytes.
898 */
899 ssthresh = (ssthresh + tp->t_maxseg / 2) / tp->t_maxseg;
900 if (ssthresh < 2)
901 ssthresh = 2;
902 ssthresh *= (u_long)(tp->t_maxseg +
903 #ifdef INET6
904 (isipv6 ? sizeof (struct ip6_hdr) +
905 sizeof (struct tcphdr) :
906 #endif
907 sizeof (struct tcpiphdr)
908 #ifdef INET6
909 )
910 #endif
911 );
912 } else
913 ssthresh = 0;
914 metrics.rmx_ssthresh = ssthresh;
915
916 metrics.rmx_rtt = tp->t_srtt;
917 metrics.rmx_rttvar = tp->t_rttvar;
918 metrics.rmx_cwnd = tp->snd_cwnd;
919 metrics.rmx_sendpipe = 0;
920 metrics.rmx_recvpipe = 0;
921
922 tcp_hc_update(&inp->inp_inc, &metrics);
923 }
924
925 /* free the reassembly queue, if any */
926 tcp_reass_flush(tp);
927 /* Disconnect offload device, if any. */
928 tcp_offload_detach(tp);
929
930 tcp_free_sackholes(tp);
931
932 /* Allow the CC algorithm to clean up after itself. */
933 if (CC_ALGO(tp)->cb_destroy != NULL)
934 CC_ALGO(tp)->cb_destroy(tp->ccv);
935
936 khelp_destroy_osd(tp->osd);
937
938 CC_ALGO(tp) = NULL;
939 inp->inp_ppcb = NULL;
940 tp->t_inpcb = NULL;
941 uma_zfree(V_tcpcb_zone, tp);
942 }
943
944 /*
945 * Attempt to close a TCP control block, marking it as dropped, and freeing
946 * the socket if we hold the only reference.
947 */
948 struct tcpcb *
949 tcp_close(struct tcpcb *tp)
950 {
951 struct inpcb *inp = tp->t_inpcb;
952 struct socket *so;
953
954 INP_INFO_WLOCK_ASSERT(&V_tcbinfo);
955 INP_WLOCK_ASSERT(inp);
956
957 /* Notify any offload devices of listener close */
958 if (tp->t_state == TCPS_LISTEN)
959 tcp_offload_listen_close(tp);
960 in_pcbdrop(inp);
961 TCPSTAT_INC(tcps_closed);
962 KASSERT(inp->inp_socket != NULL, ("tcp_close: inp_socket NULL"));
963 so = inp->inp_socket;
964 soisdisconnected(so);
965 if (inp->inp_flags & INP_SOCKREF) {
966 KASSERT(so->so_state & SS_PROTOREF,
967 ("tcp_close: !SS_PROTOREF"));
968 inp->inp_flags &= ~INP_SOCKREF;
969 INP_WUNLOCK(inp);
970 ACCEPT_LOCK();
971 SOCK_LOCK(so);
972 so->so_state &= ~SS_PROTOREF;
973 sofree(so);
974 return (NULL);
975 }
976 return (tp);
977 }
978
979 void
980 tcp_drain(void)
981 {
982 VNET_ITERATOR_DECL(vnet_iter);
983
984 if (!do_tcpdrain)
985 return;
986
987 VNET_LIST_RLOCK_NOSLEEP();
988 VNET_FOREACH(vnet_iter) {
989 CURVNET_SET(vnet_iter);
990 struct inpcb *inpb;
991 struct tcpcb *tcpb;
992
993 /*
994 * Walk the tcpbs, if existing, and flush the reassembly queue,
995 * if there is one...
996 * XXX: The "Net/3" implementation doesn't imply that the TCP
997 * reassembly queue should be flushed, but in a situation
998 * where we're really low on mbufs, this is potentially
999 * usefull.
1000 */
1001 INP_INFO_RLOCK(&V_tcbinfo);
1002 LIST_FOREACH(inpb, V_tcbinfo.ipi_listhead, inp_list) {
1003 if (inpb->inp_flags & INP_TIMEWAIT)
1004 continue;
1005 INP_WLOCK(inpb);
1006 if ((tcpb = intotcpcb(inpb)) != NULL) {
1007 tcp_reass_flush(tcpb);
1008 tcp_clean_sackreport(tcpb);
1009 }
1010 INP_WUNLOCK(inpb);
1011 }
1012 INP_INFO_RUNLOCK(&V_tcbinfo);
1013 CURVNET_RESTORE();
1014 }
1015 VNET_LIST_RUNLOCK_NOSLEEP();
1016 }
1017
1018 /*
1019 * Notify a tcp user of an asynchronous error;
1020 * store error as soft error, but wake up user
1021 * (for now, won't do anything until can select for soft error).
1022 *
1023 * Do not wake up user since there currently is no mechanism for
1024 * reporting soft errors (yet - a kqueue filter may be added).
1025 */
1026 static struct inpcb *
1027 tcp_notify(struct inpcb *inp, int error)
1028 {
1029 struct tcpcb *tp;
1030
1031 INP_INFO_WLOCK_ASSERT(&V_tcbinfo);
1032 INP_WLOCK_ASSERT(inp);
1033
1034 if ((inp->inp_flags & INP_TIMEWAIT) ||
1035 (inp->inp_flags & INP_DROPPED))
1036 return (inp);
1037
1038 tp = intotcpcb(inp);
1039 KASSERT(tp != NULL, ("tcp_notify: tp == NULL"));
1040
1041 /*
1042 * Ignore some errors if we are hooked up.
1043 * If connection hasn't completed, has retransmitted several times,
1044 * and receives a second error, give up now. This is better
1045 * than waiting a long time to establish a connection that
1046 * can never complete.
1047 */
1048 if (tp->t_state == TCPS_ESTABLISHED &&
1049 (error == EHOSTUNREACH || error == ENETUNREACH ||
1050 error == EHOSTDOWN)) {
1051 return (inp);
1052 } else if (tp->t_state < TCPS_ESTABLISHED && tp->t_rxtshift > 3 &&
1053 tp->t_softerror) {
1054 tp = tcp_drop(tp, error);
1055 if (tp != NULL)
1056 return (inp);
1057 else
1058 return (NULL);
1059 } else {
1060 tp->t_softerror = error;
1061 return (inp);
1062 }
1063 #if 0
1064 wakeup( &so->so_timeo);
1065 sorwakeup(so);
1066 sowwakeup(so);
1067 #endif
1068 }
1069
1070 static int
1071 tcp_pcblist(SYSCTL_HANDLER_ARGS)
1072 {
1073 int error, i, m, n, pcb_count;
1074 struct inpcb *inp, **inp_list;
1075 inp_gen_t gencnt;
1076 struct xinpgen xig;
1077
1078 /*
1079 * The process of preparing the TCB list is too time-consuming and
1080 * resource-intensive to repeat twice on every request.
1081 */
1082 if (req->oldptr == NULL) {
1083 n = V_tcbinfo.ipi_count + syncache_pcbcount();
1084 n += imax(n / 8, 10);
1085 req->oldidx = 2 * (sizeof xig) + n * sizeof(struct xtcpcb);
1086 return (0);
1087 }
1088
1089 if (req->newptr != NULL)
1090 return (EPERM);
1091
1092 /*
1093 * OK, now we're committed to doing something.
1094 */
1095 INP_INFO_RLOCK(&V_tcbinfo);
1096 gencnt = V_tcbinfo.ipi_gencnt;
1097 n = V_tcbinfo.ipi_count;
1098 INP_INFO_RUNLOCK(&V_tcbinfo);
1099
1100 m = syncache_pcbcount();
1101
1102 error = sysctl_wire_old_buffer(req, 2 * (sizeof xig)
1103 + (n + m) * sizeof(struct xtcpcb));
1104 if (error != 0)
1105 return (error);
1106
1107 xig.xig_len = sizeof xig;
1108 xig.xig_count = n + m;
1109 xig.xig_gen = gencnt;
1110 xig.xig_sogen = so_gencnt;
1111 error = SYSCTL_OUT(req, &xig, sizeof xig);
1112 if (error)
1113 return (error);
1114
1115 error = syncache_pcblist(req, m, &pcb_count);
1116 if (error)
1117 return (error);
1118
1119 inp_list = malloc(n * sizeof *inp_list, M_TEMP, M_WAITOK);
1120 if (inp_list == NULL)
1121 return (ENOMEM);
1122
1123 INP_INFO_RLOCK(&V_tcbinfo);
1124 for (inp = LIST_FIRST(V_tcbinfo.ipi_listhead), i = 0;
1125 inp != NULL && i < n; inp = LIST_NEXT(inp, inp_list)) {
1126 INP_WLOCK(inp);
1127 if (inp->inp_gencnt <= gencnt) {
1128 /*
1129 * XXX: This use of cr_cansee(), introduced with
1130 * TCP state changes, is not quite right, but for
1131 * now, better than nothing.
1132 */
1133 if (inp->inp_flags & INP_TIMEWAIT) {
1134 if (intotw(inp) != NULL)
1135 error = cr_cansee(req->td->td_ucred,
1136 intotw(inp)->tw_cred);
1137 else
1138 error = EINVAL; /* Skip this inp. */
1139 } else
1140 error = cr_canseeinpcb(req->td->td_ucred, inp);
1141 if (error == 0) {
1142 in_pcbref(inp);
1143 inp_list[i++] = inp;
1144 }
1145 }
1146 INP_WUNLOCK(inp);
1147 }
1148 INP_INFO_RUNLOCK(&V_tcbinfo);
1149 n = i;
1150
1151 error = 0;
1152 for (i = 0; i < n; i++) {
1153 inp = inp_list[i];
1154 INP_RLOCK(inp);
1155 if (inp->inp_gencnt <= gencnt) {
1156 struct xtcpcb xt;
1157 void *inp_ppcb;
1158
1159 bzero(&xt, sizeof(xt));
1160 xt.xt_len = sizeof xt;
1161 /* XXX should avoid extra copy */
1162 bcopy(inp, &xt.xt_inp, sizeof *inp);
1163 inp_ppcb = inp->inp_ppcb;
1164 if (inp_ppcb == NULL)
1165 bzero((char *) &xt.xt_tp, sizeof xt.xt_tp);
1166 else if (inp->inp_flags & INP_TIMEWAIT) {
1167 bzero((char *) &xt.xt_tp, sizeof xt.xt_tp);
1168 xt.xt_tp.t_state = TCPS_TIME_WAIT;
1169 } else {
1170 bcopy(inp_ppcb, &xt.xt_tp, sizeof xt.xt_tp);
1171 if (xt.xt_tp.t_timers)
1172 tcp_timer_to_xtimer(&xt.xt_tp, xt.xt_tp.t_timers, &xt.xt_timer);
1173 }
1174 if (inp->inp_socket != NULL)
1175 sotoxsocket(inp->inp_socket, &xt.xt_socket);
1176 else {
1177 bzero(&xt.xt_socket, sizeof xt.xt_socket);
1178 xt.xt_socket.xso_protocol = IPPROTO_TCP;
1179 }
1180 xt.xt_inp.inp_gencnt = inp->inp_gencnt;
1181 INP_RUNLOCK(inp);
1182 error = SYSCTL_OUT(req, &xt, sizeof xt);
1183 } else
1184 INP_RUNLOCK(inp);
1185 }
1186 INP_INFO_WLOCK(&V_tcbinfo);
1187 for (i = 0; i < n; i++) {
1188 inp = inp_list[i];
1189 INP_RLOCK(inp);
1190 if (!in_pcbrele_rlocked(inp))
1191 INP_RUNLOCK(inp);
1192 }
1193 INP_INFO_WUNLOCK(&V_tcbinfo);
1194
1195 if (!error) {
1196 /*
1197 * Give the user an updated idea of our state.
1198 * If the generation differs from what we told
1199 * her before, she knows that something happened
1200 * while we were processing this request, and it
1201 * might be necessary to retry.
1202 */
1203 INP_INFO_RLOCK(&V_tcbinfo);
1204 xig.xig_gen = V_tcbinfo.ipi_gencnt;
1205 xig.xig_sogen = so_gencnt;
1206 xig.xig_count = V_tcbinfo.ipi_count + pcb_count;
1207 INP_INFO_RUNLOCK(&V_tcbinfo);
1208 error = SYSCTL_OUT(req, &xig, sizeof xig);
1209 }
1210 free(inp_list, M_TEMP);
1211 return (error);
1212 }
1213
1214 SYSCTL_PROC(_net_inet_tcp, TCPCTL_PCBLIST, pcblist,
1215 CTLTYPE_OPAQUE | CTLFLAG_RD, NULL, 0,
1216 tcp_pcblist, "S,xtcpcb", "List of active TCP connections");
1217
1218 #ifdef INET
1219 static int
1220 tcp_getcred(SYSCTL_HANDLER_ARGS)
1221 {
1222 struct xucred xuc;
1223 struct sockaddr_in addrs[2];
1224 struct inpcb *inp;
1225 int error;
1226
1227 error = priv_check(req->td, PRIV_NETINET_GETCRED);
1228 if (error)
1229 return (error);
1230 error = SYSCTL_IN(req, addrs, sizeof(addrs));
1231 if (error)
1232 return (error);
1233 inp = in_pcblookup(&V_tcbinfo, addrs[1].sin_addr, addrs[1].sin_port,
1234 addrs[0].sin_addr, addrs[0].sin_port, INPLOOKUP_RLOCKPCB, NULL);
1235 if (inp != NULL) {
1236 if (inp->inp_socket == NULL)
1237 error = ENOENT;
1238 if (error == 0)
1239 error = cr_canseeinpcb(req->td->td_ucred, inp);
1240 if (error == 0)
1241 cru2x(inp->inp_cred, &xuc);
1242 INP_RUNLOCK(inp);
1243 } else
1244 error = ENOENT;
1245 if (error == 0)
1246 error = SYSCTL_OUT(req, &xuc, sizeof(struct xucred));
1247 return (error);
1248 }
1249
1250 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, getcred,
1251 CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_PRISON, 0, 0,
1252 tcp_getcred, "S,xucred", "Get the xucred of a TCP connection");
1253 #endif /* INET */
1254
1255 #ifdef INET6
1256 static int
1257 tcp6_getcred(SYSCTL_HANDLER_ARGS)
1258 {
1259 struct xucred xuc;
1260 struct sockaddr_in6 addrs[2];
1261 struct inpcb *inp;
1262 int error;
1263 #ifdef INET
1264 int mapped = 0;
1265 #endif
1266
1267 error = priv_check(req->td, PRIV_NETINET_GETCRED);
1268 if (error)
1269 return (error);
1270 error = SYSCTL_IN(req, addrs, sizeof(addrs));
1271 if (error)
1272 return (error);
1273 if ((error = sa6_embedscope(&addrs[0], V_ip6_use_defzone)) != 0 ||
1274 (error = sa6_embedscope(&addrs[1], V_ip6_use_defzone)) != 0) {
1275 return (error);
1276 }
1277 if (IN6_IS_ADDR_V4MAPPED(&addrs[0].sin6_addr)) {
1278 #ifdef INET
1279 if (IN6_IS_ADDR_V4MAPPED(&addrs[1].sin6_addr))
1280 mapped = 1;
1281 else
1282 #endif
1283 return (EINVAL);
1284 }
1285
1286 #ifdef INET
1287 if (mapped == 1)
1288 inp = in_pcblookup(&V_tcbinfo,
1289 *(struct in_addr *)&addrs[1].sin6_addr.s6_addr[12],
1290 addrs[1].sin6_port,
1291 *(struct in_addr *)&addrs[0].sin6_addr.s6_addr[12],
1292 addrs[0].sin6_port, INPLOOKUP_RLOCKPCB, NULL);
1293 else
1294 #endif
1295 inp = in6_pcblookup(&V_tcbinfo,
1296 &addrs[1].sin6_addr, addrs[1].sin6_port,
1297 &addrs[0].sin6_addr, addrs[0].sin6_port,
1298 INPLOOKUP_RLOCKPCB, NULL);
1299 if (inp != NULL) {
1300 if (inp->inp_socket == NULL)
1301 error = ENOENT;
1302 if (error == 0)
1303 error = cr_canseeinpcb(req->td->td_ucred, inp);
1304 if (error == 0)
1305 cru2x(inp->inp_cred, &xuc);
1306 INP_RUNLOCK(inp);
1307 } else
1308 error = ENOENT;
1309 if (error == 0)
1310 error = SYSCTL_OUT(req, &xuc, sizeof(struct xucred));
1311 return (error);
1312 }
1313
1314 SYSCTL_PROC(_net_inet6_tcp6, OID_AUTO, getcred,
1315 CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_PRISON, 0, 0,
1316 tcp6_getcred, "S,xucred", "Get the xucred of a TCP6 connection");
1317 #endif /* INET6 */
1318
1319
1320 #ifdef INET
1321 void
1322 tcp_ctlinput(int cmd, struct sockaddr *sa, void *vip)
1323 {
1324 struct ip *ip = vip;
1325 struct tcphdr *th;
1326 struct in_addr faddr;
1327 struct inpcb *inp;
1328 struct tcpcb *tp;
1329 struct inpcb *(*notify)(struct inpcb *, int) = tcp_notify;
1330 struct icmp *icp;
1331 struct in_conninfo inc;
1332 tcp_seq icmp_tcp_seq;
1333 int mtu;
1334
1335 faddr = ((struct sockaddr_in *)sa)->sin_addr;
1336 if (sa->sa_family != AF_INET || faddr.s_addr == INADDR_ANY)
1337 return;
1338
1339 if (cmd == PRC_MSGSIZE)
1340 notify = tcp_mtudisc_notify;
1341 else if (V_icmp_may_rst && (cmd == PRC_UNREACH_ADMIN_PROHIB ||
1342 cmd == PRC_UNREACH_PORT || cmd == PRC_TIMXCEED_INTRANS) && ip)
1343 notify = tcp_drop_syn_sent;
1344 /*
1345 * Redirects don't need to be handled up here.
1346 */
1347 else if (PRC_IS_REDIRECT(cmd))
1348 return;
1349 /*
1350 * Source quench is depreciated.
1351 */
1352 else if (cmd == PRC_QUENCH)
1353 return;
1354 /*
1355 * Hostdead is ugly because it goes linearly through all PCBs.
1356 * XXX: We never get this from ICMP, otherwise it makes an
1357 * excellent DoS attack on machines with many connections.
1358 */
1359 else if (cmd == PRC_HOSTDEAD)
1360 ip = NULL;
1361 else if ((unsigned)cmd >= PRC_NCMDS || inetctlerrmap[cmd] == 0)
1362 return;
1363 if (ip != NULL) {
1364 icp = (struct icmp *)((caddr_t)ip
1365 - offsetof(struct icmp, icmp_ip));
1366 th = (struct tcphdr *)((caddr_t)ip
1367 + (ip->ip_hl << 2));
1368 INP_INFO_WLOCK(&V_tcbinfo);
1369 inp = in_pcblookup(&V_tcbinfo, faddr, th->th_dport,
1370 ip->ip_src, th->th_sport, INPLOOKUP_WLOCKPCB, NULL);
1371 if (inp != NULL) {
1372 if (!(inp->inp_flags & INP_TIMEWAIT) &&
1373 !(inp->inp_flags & INP_DROPPED) &&
1374 !(inp->inp_socket == NULL)) {
1375 icmp_tcp_seq = htonl(th->th_seq);
1376 tp = intotcpcb(inp);
1377 if (SEQ_GEQ(icmp_tcp_seq, tp->snd_una) &&
1378 SEQ_LT(icmp_tcp_seq, tp->snd_max)) {
1379 if (cmd == PRC_MSGSIZE) {
1380 /*
1381 * MTU discovery:
1382 * If we got a needfrag set the MTU
1383 * in the route to the suggested new
1384 * value (if given) and then notify.
1385 */
1386 bzero(&inc, sizeof(inc));
1387 inc.inc_faddr = faddr;
1388 inc.inc_fibnum =
1389 inp->inp_inc.inc_fibnum;
1390
1391 mtu = ntohs(icp->icmp_nextmtu);
1392 /*
1393 * If no alternative MTU was
1394 * proposed, try the next smaller
1395 * one. ip->ip_len has already
1396 * been swapped in icmp_input().
1397 */
1398 if (!mtu)
1399 mtu = ip_next_mtu(ip->ip_len,
1400 1);
1401 if (mtu < V_tcp_minmss
1402 + sizeof(struct tcpiphdr))
1403 mtu = V_tcp_minmss
1404 + sizeof(struct tcpiphdr);
1405 /*
1406 * Only cache the MTU if it
1407 * is smaller than the interface
1408 * or route MTU. tcp_mtudisc()
1409 * will do right thing by itself.
1410 */
1411 if (mtu <= tcp_maxmtu(&inc, NULL))
1412 tcp_hc_updatemtu(&inc, mtu);
1413 tcp_mtudisc(inp, mtu);
1414 } else
1415 inp = (*notify)(inp,
1416 inetctlerrmap[cmd]);
1417 }
1418 }
1419 if (inp != NULL)
1420 INP_WUNLOCK(inp);
1421 } else {
1422 bzero(&inc, sizeof(inc));
1423 inc.inc_fport = th->th_dport;
1424 inc.inc_lport = th->th_sport;
1425 inc.inc_faddr = faddr;
1426 inc.inc_laddr = ip->ip_src;
1427 syncache_unreach(&inc, th);
1428 }
1429 INP_INFO_WUNLOCK(&V_tcbinfo);
1430 } else
1431 in_pcbnotifyall(&V_tcbinfo, faddr, inetctlerrmap[cmd], notify);
1432 }
1433 #endif /* INET */
1434
1435 #ifdef INET6
1436 void
1437 tcp6_ctlinput(int cmd, struct sockaddr *sa, void *d)
1438 {
1439 struct tcphdr th;
1440 struct inpcb *(*notify)(struct inpcb *, int) = tcp_notify;
1441 struct ip6_hdr *ip6;
1442 struct mbuf *m;
1443 struct ip6ctlparam *ip6cp = NULL;
1444 const struct sockaddr_in6 *sa6_src = NULL;
1445 int off;
1446 struct tcp_portonly {
1447 u_int16_t th_sport;
1448 u_int16_t th_dport;
1449 } *thp;
1450
1451 if (sa->sa_family != AF_INET6 ||
1452 sa->sa_len != sizeof(struct sockaddr_in6))
1453 return;
1454
1455 if (cmd == PRC_MSGSIZE)
1456 notify = tcp_mtudisc_notify;
1457 else if (!PRC_IS_REDIRECT(cmd) &&
1458 ((unsigned)cmd >= PRC_NCMDS || inet6ctlerrmap[cmd] == 0))
1459 return;
1460 /* Source quench is depreciated. */
1461 else if (cmd == PRC_QUENCH)
1462 return;
1463
1464 /* if the parameter is from icmp6, decode it. */
1465 if (d != NULL) {
1466 ip6cp = (struct ip6ctlparam *)d;
1467 m = ip6cp->ip6c_m;
1468 ip6 = ip6cp->ip6c_ip6;
1469 off = ip6cp->ip6c_off;
1470 sa6_src = ip6cp->ip6c_src;
1471 } else {
1472 m = NULL;
1473 ip6 = NULL;
1474 off = 0; /* fool gcc */
1475 sa6_src = &sa6_any;
1476 }
1477
1478 if (ip6 != NULL) {
1479 struct in_conninfo inc;
1480 /*
1481 * XXX: We assume that when IPV6 is non NULL,
1482 * M and OFF are valid.
1483 */
1484
1485 /* check if we can safely examine src and dst ports */
1486 if (m->m_pkthdr.len < off + sizeof(*thp))
1487 return;
1488
1489 bzero(&th, sizeof(th));
1490 m_copydata(m, off, sizeof(*thp), (caddr_t)&th);
1491
1492 in6_pcbnotify(&V_tcbinfo, sa, th.th_dport,
1493 (struct sockaddr *)ip6cp->ip6c_src,
1494 th.th_sport, cmd, NULL, notify);
1495
1496 bzero(&inc, sizeof(inc));
1497 inc.inc_fport = th.th_dport;
1498 inc.inc_lport = th.th_sport;
1499 inc.inc6_faddr = ((struct sockaddr_in6 *)sa)->sin6_addr;
1500 inc.inc6_laddr = ip6cp->ip6c_src->sin6_addr;
1501 inc.inc_flags |= INC_ISIPV6;
1502 INP_INFO_WLOCK(&V_tcbinfo);
1503 syncache_unreach(&inc, &th);
1504 INP_INFO_WUNLOCK(&V_tcbinfo);
1505 } else
1506 in6_pcbnotify(&V_tcbinfo, sa, 0, (const struct sockaddr *)sa6_src,
1507 0, cmd, NULL, notify);
1508 }
1509 #endif /* INET6 */
1510
1511
1512 /*
1513 * Following is where TCP initial sequence number generation occurs.
1514 *
1515 * There are two places where we must use initial sequence numbers:
1516 * 1. In SYN-ACK packets.
1517 * 2. In SYN packets.
1518 *
1519 * All ISNs for SYN-ACK packets are generated by the syncache. See
1520 * tcp_syncache.c for details.
1521 *
1522 * The ISNs in SYN packets must be monotonic; TIME_WAIT recycling
1523 * depends on this property. In addition, these ISNs should be
1524 * unguessable so as to prevent connection hijacking. To satisfy
1525 * the requirements of this situation, the algorithm outlined in
1526 * RFC 1948 is used, with only small modifications.
1527 *
1528 * Implementation details:
1529 *
1530 * Time is based off the system timer, and is corrected so that it
1531 * increases by one megabyte per second. This allows for proper
1532 * recycling on high speed LANs while still leaving over an hour
1533 * before rollover.
1534 *
1535 * As reading the *exact* system time is too expensive to be done
1536 * whenever setting up a TCP connection, we increment the time
1537 * offset in two ways. First, a small random positive increment
1538 * is added to isn_offset for each connection that is set up.
1539 * Second, the function tcp_isn_tick fires once per clock tick
1540 * and increments isn_offset as necessary so that sequence numbers
1541 * are incremented at approximately ISN_BYTES_PER_SECOND. The
1542 * random positive increments serve only to ensure that the same
1543 * exact sequence number is never sent out twice (as could otherwise
1544 * happen when a port is recycled in less than the system tick
1545 * interval.)
1546 *
1547 * net.inet.tcp.isn_reseed_interval controls the number of seconds
1548 * between seeding of isn_secret. This is normally set to zero,
1549 * as reseeding should not be necessary.
1550 *
1551 * Locking of the global variables isn_secret, isn_last_reseed, isn_offset,
1552 * isn_offset_old, and isn_ctx is performed using the TCP pcbinfo lock. In
1553 * general, this means holding an exclusive (write) lock.
1554 */
1555
1556 #define ISN_BYTES_PER_SECOND 1048576
1557 #define ISN_STATIC_INCREMENT 4096
1558 #define ISN_RANDOM_INCREMENT (4096 - 1)
1559
1560 static VNET_DEFINE(u_char, isn_secret[32]);
1561 static VNET_DEFINE(int, isn_last);
1562 static VNET_DEFINE(int, isn_last_reseed);
1563 static VNET_DEFINE(u_int32_t, isn_offset);
1564 static VNET_DEFINE(u_int32_t, isn_offset_old);
1565
1566 #define V_isn_secret VNET(isn_secret)
1567 #define V_isn_last VNET(isn_last)
1568 #define V_isn_last_reseed VNET(isn_last_reseed)
1569 #define V_isn_offset VNET(isn_offset)
1570 #define V_isn_offset_old VNET(isn_offset_old)
1571
1572 tcp_seq
1573 tcp_new_isn(struct tcpcb *tp)
1574 {
1575 MD5_CTX isn_ctx;
1576 u_int32_t md5_buffer[4];
1577 tcp_seq new_isn;
1578 u_int32_t projected_offset;
1579
1580 INP_WLOCK_ASSERT(tp->t_inpcb);
1581
1582 ISN_LOCK();
1583 /* Seed if this is the first use, reseed if requested. */
1584 if ((V_isn_last_reseed == 0) || ((V_tcp_isn_reseed_interval > 0) &&
1585 (((u_int)V_isn_last_reseed + (u_int)V_tcp_isn_reseed_interval*hz)
1586 < (u_int)ticks))) {
1587 read_random(&V_isn_secret, sizeof(V_isn_secret));
1588 V_isn_last_reseed = ticks;
1589 }
1590
1591 /* Compute the md5 hash and return the ISN. */
1592 MD5Init(&isn_ctx);
1593 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_fport, sizeof(u_short));
1594 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_lport, sizeof(u_short));
1595 #ifdef INET6
1596 if ((tp->t_inpcb->inp_vflag & INP_IPV6) != 0) {
1597 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->in6p_faddr,
1598 sizeof(struct in6_addr));
1599 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->in6p_laddr,
1600 sizeof(struct in6_addr));
1601 } else
1602 #endif
1603 {
1604 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_faddr,
1605 sizeof(struct in_addr));
1606 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_laddr,
1607 sizeof(struct in_addr));
1608 }
1609 MD5Update(&isn_ctx, (u_char *) &V_isn_secret, sizeof(V_isn_secret));
1610 MD5Final((u_char *) &md5_buffer, &isn_ctx);
1611 new_isn = (tcp_seq) md5_buffer[0];
1612 V_isn_offset += ISN_STATIC_INCREMENT +
1613 (arc4random() & ISN_RANDOM_INCREMENT);
1614 if (ticks != V_isn_last) {
1615 projected_offset = V_isn_offset_old +
1616 ISN_BYTES_PER_SECOND / hz * (ticks - V_isn_last);
1617 if (SEQ_GT(projected_offset, V_isn_offset))
1618 V_isn_offset = projected_offset;
1619 V_isn_offset_old = V_isn_offset;
1620 V_isn_last = ticks;
1621 }
1622 new_isn += V_isn_offset;
1623 ISN_UNLOCK();
1624 return (new_isn);
1625 }
1626
1627 /*
1628 * When a specific ICMP unreachable message is received and the
1629 * connection state is SYN-SENT, drop the connection. This behavior
1630 * is controlled by the icmp_may_rst sysctl.
1631 */
1632 struct inpcb *
1633 tcp_drop_syn_sent(struct inpcb *inp, int errno)
1634 {
1635 struct tcpcb *tp;
1636
1637 INP_INFO_WLOCK_ASSERT(&V_tcbinfo);
1638 INP_WLOCK_ASSERT(inp);
1639
1640 if ((inp->inp_flags & INP_TIMEWAIT) ||
1641 (inp->inp_flags & INP_DROPPED))
1642 return (inp);
1643
1644 tp = intotcpcb(inp);
1645 if (tp->t_state != TCPS_SYN_SENT)
1646 return (inp);
1647
1648 tp = tcp_drop(tp, errno);
1649 if (tp != NULL)
1650 return (inp);
1651 else
1652 return (NULL);
1653 }
1654
1655 /*
1656 * When `need fragmentation' ICMP is received, update our idea of the MSS
1657 * based on the new value. Also nudge TCP to send something, since we
1658 * know the packet we just sent was dropped.
1659 * This duplicates some code in the tcp_mss() function in tcp_input.c.
1660 */
1661 static struct inpcb *
1662 tcp_mtudisc_notify(struct inpcb *inp, int error)
1663 {
1664
1665 return (tcp_mtudisc(inp, -1));
1666 }
1667
1668 struct inpcb *
1669 tcp_mtudisc(struct inpcb *inp, int mtuoffer)
1670 {
1671 struct tcpcb *tp;
1672 struct socket *so;
1673
1674 INP_WLOCK_ASSERT(inp);
1675 if ((inp->inp_flags & INP_TIMEWAIT) ||
1676 (inp->inp_flags & INP_DROPPED))
1677 return (inp);
1678
1679 tp = intotcpcb(inp);
1680 KASSERT(tp != NULL, ("tcp_mtudisc: tp == NULL"));
1681
1682 tcp_mss_update(tp, -1, mtuoffer, NULL, NULL);
1683
1684 so = inp->inp_socket;
1685 SOCKBUF_LOCK(&so->so_snd);
1686 /* If the mss is larger than the socket buffer, decrease the mss. */
1687 if (so->so_snd.sb_hiwat < tp->t_maxseg)
1688 tp->t_maxseg = so->so_snd.sb_hiwat;
1689 SOCKBUF_UNLOCK(&so->so_snd);
1690
1691 TCPSTAT_INC(tcps_mturesent);
1692 tp->t_rtttime = 0;
1693 tp->snd_nxt = tp->snd_una;
1694 tcp_free_sackholes(tp);
1695 tp->snd_recover = tp->snd_max;
1696 if (tp->t_flags & TF_SACK_PERMIT)
1697 EXIT_FASTRECOVERY(tp->t_flags);
1698 tcp_output_send(tp);
1699 return (inp);
1700 }
1701
1702 #ifdef INET
1703 /*
1704 * Look-up the routing entry to the peer of this inpcb. If no route
1705 * is found and it cannot be allocated, then return 0. This routine
1706 * is called by TCP routines that access the rmx structure and by
1707 * tcp_mss_update to get the peer/interface MTU.
1708 */
1709 u_long
1710 tcp_maxmtu(struct in_conninfo *inc, int *flags)
1711 {
1712 struct route sro;
1713 struct sockaddr_in *dst;
1714 struct ifnet *ifp;
1715 u_long maxmtu = 0;
1716
1717 KASSERT(inc != NULL, ("tcp_maxmtu with NULL in_conninfo pointer"));
1718
1719 bzero(&sro, sizeof(sro));
1720 if (inc->inc_faddr.s_addr != INADDR_ANY) {
1721 dst = (struct sockaddr_in *)&sro.ro_dst;
1722 dst->sin_family = AF_INET;
1723 dst->sin_len = sizeof(*dst);
1724 dst->sin_addr = inc->inc_faddr;
1725 in_rtalloc_ign(&sro, 0, inc->inc_fibnum);
1726 }
1727 if (sro.ro_rt != NULL) {
1728 ifp = sro.ro_rt->rt_ifp;
1729 if (sro.ro_rt->rt_rmx.rmx_mtu == 0)
1730 maxmtu = ifp->if_mtu;
1731 else
1732 maxmtu = min(sro.ro_rt->rt_rmx.rmx_mtu, ifp->if_mtu);
1733
1734 /* Report additional interface capabilities. */
1735 if (flags != NULL) {
1736 if (ifp->if_capenable & IFCAP_TSO4 &&
1737 ifp->if_hwassist & CSUM_TSO)
1738 *flags |= CSUM_TSO;
1739 }
1740 RTFREE(sro.ro_rt);
1741 }
1742 return (maxmtu);
1743 }
1744 #endif /* INET */
1745
1746 #ifdef INET6
1747 u_long
1748 tcp_maxmtu6(struct in_conninfo *inc, int *flags)
1749 {
1750 struct route_in6 sro6;
1751 struct ifnet *ifp;
1752 u_long maxmtu = 0;
1753
1754 KASSERT(inc != NULL, ("tcp_maxmtu6 with NULL in_conninfo pointer"));
1755
1756 bzero(&sro6, sizeof(sro6));
1757 if (!IN6_IS_ADDR_UNSPECIFIED(&inc->inc6_faddr)) {
1758 sro6.ro_dst.sin6_family = AF_INET6;
1759 sro6.ro_dst.sin6_len = sizeof(struct sockaddr_in6);
1760 sro6.ro_dst.sin6_addr = inc->inc6_faddr;
1761 in6_rtalloc_ign(&sro6, 0, inc->inc_fibnum);
1762 }
1763 if (sro6.ro_rt != NULL) {
1764 ifp = sro6.ro_rt->rt_ifp;
1765 if (sro6.ro_rt->rt_rmx.rmx_mtu == 0)
1766 maxmtu = IN6_LINKMTU(sro6.ro_rt->rt_ifp);
1767 else
1768 maxmtu = min(sro6.ro_rt->rt_rmx.rmx_mtu,
1769 IN6_LINKMTU(sro6.ro_rt->rt_ifp));
1770
1771 /* Report additional interface capabilities. */
1772 if (flags != NULL) {
1773 if (ifp->if_capenable & IFCAP_TSO6 &&
1774 ifp->if_hwassist & CSUM_TSO)
1775 *flags |= CSUM_TSO;
1776 }
1777 RTFREE(sro6.ro_rt);
1778 }
1779
1780 return (maxmtu);
1781 }
1782 #endif /* INET6 */
1783
1784 #ifdef IPSEC
1785 /* compute ESP/AH header size for TCP, including outer IP header. */
1786 size_t
1787 ipsec_hdrsiz_tcp(struct tcpcb *tp)
1788 {
1789 struct inpcb *inp;
1790 struct mbuf *m;
1791 size_t hdrsiz;
1792 struct ip *ip;
1793 #ifdef INET6
1794 struct ip6_hdr *ip6;
1795 #endif
1796 struct tcphdr *th;
1797
1798 if ((tp == NULL) || ((inp = tp->t_inpcb) == NULL))
1799 return (0);
1800 MGETHDR(m, M_DONTWAIT, MT_DATA);
1801 if (!m)
1802 return (0);
1803
1804 #ifdef INET6
1805 if ((inp->inp_vflag & INP_IPV6) != 0) {
1806 ip6 = mtod(m, struct ip6_hdr *);
1807 th = (struct tcphdr *)(ip6 + 1);
1808 m->m_pkthdr.len = m->m_len =
1809 sizeof(struct ip6_hdr) + sizeof(struct tcphdr);
1810 tcpip_fillheaders(inp, ip6, th);
1811 hdrsiz = ipsec_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp);
1812 } else
1813 #endif /* INET6 */
1814 {
1815 ip = mtod(m, struct ip *);
1816 th = (struct tcphdr *)(ip + 1);
1817 m->m_pkthdr.len = m->m_len = sizeof(struct tcpiphdr);
1818 tcpip_fillheaders(inp, ip, th);
1819 hdrsiz = ipsec_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp);
1820 }
1821
1822 m_free(m);
1823 return (hdrsiz);
1824 }
1825 #endif /* IPSEC */
1826
1827 #ifdef TCP_SIGNATURE
1828 /*
1829 * Callback function invoked by m_apply() to digest TCP segment data
1830 * contained within an mbuf chain.
1831 */
1832 static int
1833 tcp_signature_apply(void *fstate, void *data, u_int len)
1834 {
1835
1836 MD5Update(fstate, (u_char *)data, len);
1837 return (0);
1838 }
1839
1840 /*
1841 * Compute TCP-MD5 hash of a TCP segment. (RFC2385)
1842 *
1843 * Parameters:
1844 * m pointer to head of mbuf chain
1845 * _unused
1846 * len length of TCP segment data, excluding options
1847 * optlen length of TCP segment options
1848 * buf pointer to storage for computed MD5 digest
1849 * direction direction of flow (IPSEC_DIR_INBOUND or OUTBOUND)
1850 *
1851 * We do this over ip, tcphdr, segment data, and the key in the SADB.
1852 * When called from tcp_input(), we can be sure that th_sum has been
1853 * zeroed out and verified already.
1854 *
1855 * Return 0 if successful, otherwise return -1.
1856 *
1857 * XXX The key is retrieved from the system's PF_KEY SADB, by keying a
1858 * search with the destination IP address, and a 'magic SPI' to be
1859 * determined by the application. This is hardcoded elsewhere to 1179
1860 * right now. Another branch of this code exists which uses the SPD to
1861 * specify per-application flows but it is unstable.
1862 */
1863 int
1864 tcp_signature_compute(struct mbuf *m, int _unused, int len, int optlen,
1865 u_char *buf, u_int direction)
1866 {
1867 union sockaddr_union dst;
1868 #ifdef INET
1869 struct ippseudo ippseudo;
1870 #endif
1871 MD5_CTX ctx;
1872 int doff;
1873 struct ip *ip;
1874 #ifdef INET
1875 struct ipovly *ipovly;
1876 #endif
1877 struct secasvar *sav;
1878 struct tcphdr *th;
1879 #ifdef INET6
1880 struct ip6_hdr *ip6;
1881 struct in6_addr in6;
1882 char ip6buf[INET6_ADDRSTRLEN];
1883 uint32_t plen;
1884 uint16_t nhdr;
1885 #endif
1886 u_short savecsum;
1887
1888 KASSERT(m != NULL, ("NULL mbuf chain"));
1889 KASSERT(buf != NULL, ("NULL signature pointer"));
1890
1891 /* Extract the destination from the IP header in the mbuf. */
1892 bzero(&dst, sizeof(union sockaddr_union));
1893 ip = mtod(m, struct ip *);
1894 #ifdef INET6
1895 ip6 = NULL; /* Make the compiler happy. */
1896 #endif
1897 switch (ip->ip_v) {
1898 #ifdef INET
1899 case IPVERSION:
1900 dst.sa.sa_len = sizeof(struct sockaddr_in);
1901 dst.sa.sa_family = AF_INET;
1902 dst.sin.sin_addr = (direction == IPSEC_DIR_INBOUND) ?
1903 ip->ip_src : ip->ip_dst;
1904 break;
1905 #endif
1906 #ifdef INET6
1907 case (IPV6_VERSION >> 4):
1908 ip6 = mtod(m, struct ip6_hdr *);
1909 dst.sa.sa_len = sizeof(struct sockaddr_in6);
1910 dst.sa.sa_family = AF_INET6;
1911 dst.sin6.sin6_addr = (direction == IPSEC_DIR_INBOUND) ?
1912 ip6->ip6_src : ip6->ip6_dst;
1913 break;
1914 #endif
1915 default:
1916 return (EINVAL);
1917 /* NOTREACHED */
1918 break;
1919 }
1920
1921 /* Look up an SADB entry which matches the address of the peer. */
1922 sav = KEY_ALLOCSA(&dst, IPPROTO_TCP, htonl(TCP_SIG_SPI));
1923 if (sav == NULL) {
1924 ipseclog((LOG_ERR, "%s: SADB lookup failed for %s\n", __func__,
1925 (ip->ip_v == IPVERSION) ? inet_ntoa(dst.sin.sin_addr) :
1926 #ifdef INET6
1927 (ip->ip_v == (IPV6_VERSION >> 4)) ?
1928 ip6_sprintf(ip6buf, &dst.sin6.sin6_addr) :
1929 #endif
1930 "(unsupported)"));
1931 return (EINVAL);
1932 }
1933
1934 MD5Init(&ctx);
1935 /*
1936 * Step 1: Update MD5 hash with IP(v6) pseudo-header.
1937 *
1938 * XXX The ippseudo header MUST be digested in network byte order,
1939 * or else we'll fail the regression test. Assume all fields we've
1940 * been doing arithmetic on have been in host byte order.
1941 * XXX One cannot depend on ipovly->ih_len here. When called from
1942 * tcp_output(), the underlying ip_len member has not yet been set.
1943 */
1944 switch (ip->ip_v) {
1945 #ifdef INET
1946 case IPVERSION:
1947 ipovly = (struct ipovly *)ip;
1948 ippseudo.ippseudo_src = ipovly->ih_src;
1949 ippseudo.ippseudo_dst = ipovly->ih_dst;
1950 ippseudo.ippseudo_pad = 0;
1951 ippseudo.ippseudo_p = IPPROTO_TCP;
1952 ippseudo.ippseudo_len = htons(len + sizeof(struct tcphdr) +
1953 optlen);
1954 MD5Update(&ctx, (char *)&ippseudo, sizeof(struct ippseudo));
1955
1956 th = (struct tcphdr *)((u_char *)ip + sizeof(struct ip));
1957 doff = sizeof(struct ip) + sizeof(struct tcphdr) + optlen;
1958 break;
1959 #endif
1960 #ifdef INET6
1961 /*
1962 * RFC 2385, 2.0 Proposal
1963 * For IPv6, the pseudo-header is as described in RFC 2460, namely the
1964 * 128-bit source IPv6 address, 128-bit destination IPv6 address, zero-
1965 * extended next header value (to form 32 bits), and 32-bit segment
1966 * length.
1967 * Note: Upper-Layer Packet Length comes before Next Header.
1968 */
1969 case (IPV6_VERSION >> 4):
1970 in6 = ip6->ip6_src;
1971 in6_clearscope(&in6);
1972 MD5Update(&ctx, (char *)&in6, sizeof(struct in6_addr));
1973 in6 = ip6->ip6_dst;
1974 in6_clearscope(&in6);
1975 MD5Update(&ctx, (char *)&in6, sizeof(struct in6_addr));
1976 plen = htonl(len + sizeof(struct tcphdr) + optlen);
1977 MD5Update(&ctx, (char *)&plen, sizeof(uint32_t));
1978 nhdr = 0;
1979 MD5Update(&ctx, (char *)&nhdr, sizeof(uint8_t));
1980 MD5Update(&ctx, (char *)&nhdr, sizeof(uint8_t));
1981 MD5Update(&ctx, (char *)&nhdr, sizeof(uint8_t));
1982 nhdr = IPPROTO_TCP;
1983 MD5Update(&ctx, (char *)&nhdr, sizeof(uint8_t));
1984
1985 th = (struct tcphdr *)((u_char *)ip6 + sizeof(struct ip6_hdr));
1986 doff = sizeof(struct ip6_hdr) + sizeof(struct tcphdr) + optlen;
1987 break;
1988 #endif
1989 default:
1990 return (EINVAL);
1991 /* NOTREACHED */
1992 break;
1993 }
1994
1995
1996 /*
1997 * Step 2: Update MD5 hash with TCP header, excluding options.
1998 * The TCP checksum must be set to zero.
1999 */
2000 savecsum = th->th_sum;
2001 th->th_sum = 0;
2002 MD5Update(&ctx, (char *)th, sizeof(struct tcphdr));
2003 th->th_sum = savecsum;
2004
2005 /*
2006 * Step 3: Update MD5 hash with TCP segment data.
2007 * Use m_apply() to avoid an early m_pullup().
2008 */
2009 if (len > 0)
2010 m_apply(m, doff, len, tcp_signature_apply, &ctx);
2011
2012 /*
2013 * Step 4: Update MD5 hash with shared secret.
2014 */
2015 MD5Update(&ctx, sav->key_auth->key_data, _KEYLEN(sav->key_auth));
2016 MD5Final(buf, &ctx);
2017
2018 key_sa_recordxfer(sav, m);
2019 KEY_FREESAV(&sav);
2020 return (0);
2021 }
2022
2023 /*
2024 * Verify the TCP-MD5 hash of a TCP segment. (RFC2385)
2025 *
2026 * Parameters:
2027 * m pointer to head of mbuf chain
2028 * len length of TCP segment data, excluding options
2029 * optlen length of TCP segment options
2030 * buf pointer to storage for computed MD5 digest
2031 * direction direction of flow (IPSEC_DIR_INBOUND or OUTBOUND)
2032 *
2033 * Return 1 if successful, otherwise return 0.
2034 */
2035 int
2036 tcp_signature_verify(struct mbuf *m, int off0, int tlen, int optlen,
2037 struct tcpopt *to, struct tcphdr *th, u_int tcpbflag)
2038 {
2039 char tmpdigest[TCP_SIGLEN];
2040
2041 if (tcp_sig_checksigs == 0)
2042 return (1);
2043 if ((tcpbflag & TF_SIGNATURE) == 0) {
2044 if ((to->to_flags & TOF_SIGNATURE) != 0) {
2045
2046 /*
2047 * If this socket is not expecting signature but
2048 * the segment contains signature just fail.
2049 */
2050 TCPSTAT_INC(tcps_sig_err_sigopt);
2051 TCPSTAT_INC(tcps_sig_rcvbadsig);
2052 return (0);
2053 }
2054
2055 /* Signature is not expected, and not present in segment. */
2056 return (1);
2057 }
2058
2059 /*
2060 * If this socket is expecting signature but the segment does not
2061 * contain any just fail.
2062 */
2063 if ((to->to_flags & TOF_SIGNATURE) == 0) {
2064 TCPSTAT_INC(tcps_sig_err_nosigopt);
2065 TCPSTAT_INC(tcps_sig_rcvbadsig);
2066 return (0);
2067 }
2068 if (tcp_signature_compute(m, off0, tlen, optlen, &tmpdigest[0],
2069 IPSEC_DIR_INBOUND) == -1) {
2070 TCPSTAT_INC(tcps_sig_err_buildsig);
2071 TCPSTAT_INC(tcps_sig_rcvbadsig);
2072 return (0);
2073 }
2074
2075 if (bcmp(to->to_signature, &tmpdigest[0], TCP_SIGLEN) != 0) {
2076 TCPSTAT_INC(tcps_sig_rcvbadsig);
2077 return (0);
2078 }
2079 TCPSTAT_INC(tcps_sig_rcvgoodsig);
2080 return (1);
2081 }
2082 #endif /* TCP_SIGNATURE */
2083
2084 static int
2085 sysctl_drop(SYSCTL_HANDLER_ARGS)
2086 {
2087 /* addrs[0] is a foreign socket, addrs[1] is a local one. */
2088 struct sockaddr_storage addrs[2];
2089 struct inpcb *inp;
2090 struct tcpcb *tp;
2091 struct tcptw *tw;
2092 struct sockaddr_in *fin, *lin;
2093 #ifdef INET6
2094 struct sockaddr_in6 *fin6, *lin6;
2095 #endif
2096 int error;
2097
2098 inp = NULL;
2099 fin = lin = NULL;
2100 #ifdef INET6
2101 fin6 = lin6 = NULL;
2102 #endif
2103 error = 0;
2104
2105 if (req->oldptr != NULL || req->oldlen != 0)
2106 return (EINVAL);
2107 if (req->newptr == NULL)
2108 return (EPERM);
2109 if (req->newlen < sizeof(addrs))
2110 return (ENOMEM);
2111 error = SYSCTL_IN(req, &addrs, sizeof(addrs));
2112 if (error)
2113 return (error);
2114
2115 switch (addrs[0].ss_family) {
2116 #ifdef INET6
2117 case AF_INET6:
2118 fin6 = (struct sockaddr_in6 *)&addrs[0];
2119 lin6 = (struct sockaddr_in6 *)&addrs[1];
2120 if (fin6->sin6_len != sizeof(struct sockaddr_in6) ||
2121 lin6->sin6_len != sizeof(struct sockaddr_in6))
2122 return (EINVAL);
2123 if (IN6_IS_ADDR_V4MAPPED(&fin6->sin6_addr)) {
2124 if (!IN6_IS_ADDR_V4MAPPED(&lin6->sin6_addr))
2125 return (EINVAL);
2126 in6_sin6_2_sin_in_sock((struct sockaddr *)&addrs[0]);
2127 in6_sin6_2_sin_in_sock((struct sockaddr *)&addrs[1]);
2128 fin = (struct sockaddr_in *)&addrs[0];
2129 lin = (struct sockaddr_in *)&addrs[1];
2130 break;
2131 }
2132 error = sa6_embedscope(fin6, V_ip6_use_defzone);
2133 if (error)
2134 return (error);
2135 error = sa6_embedscope(lin6, V_ip6_use_defzone);
2136 if (error)
2137 return (error);
2138 break;
2139 #endif
2140 #ifdef INET
2141 case AF_INET:
2142 fin = (struct sockaddr_in *)&addrs[0];
2143 lin = (struct sockaddr_in *)&addrs[1];
2144 if (fin->sin_len != sizeof(struct sockaddr_in) ||
2145 lin->sin_len != sizeof(struct sockaddr_in))
2146 return (EINVAL);
2147 break;
2148 #endif
2149 default:
2150 return (EINVAL);
2151 }
2152 INP_INFO_WLOCK(&V_tcbinfo);
2153 switch (addrs[0].ss_family) {
2154 #ifdef INET6
2155 case AF_INET6:
2156 inp = in6_pcblookup(&V_tcbinfo, &fin6->sin6_addr,
2157 fin6->sin6_port, &lin6->sin6_addr, lin6->sin6_port,
2158 INPLOOKUP_WLOCKPCB, NULL);
2159 break;
2160 #endif
2161 #ifdef INET
2162 case AF_INET:
2163 inp = in_pcblookup(&V_tcbinfo, fin->sin_addr, fin->sin_port,
2164 lin->sin_addr, lin->sin_port, INPLOOKUP_WLOCKPCB, NULL);
2165 break;
2166 #endif
2167 }
2168 if (inp != NULL) {
2169 if (inp->inp_flags & INP_TIMEWAIT) {
2170 /*
2171 * XXXRW: There currently exists a state where an
2172 * inpcb is present, but its timewait state has been
2173 * discarded. For now, don't allow dropping of this
2174 * type of inpcb.
2175 */
2176 tw = intotw(inp);
2177 if (tw != NULL)
2178 tcp_twclose(tw, 0);
2179 else
2180 INP_WUNLOCK(inp);
2181 } else if (!(inp->inp_flags & INP_DROPPED) &&
2182 !(inp->inp_socket->so_options & SO_ACCEPTCONN)) {
2183 tp = intotcpcb(inp);
2184 tp = tcp_drop(tp, ECONNABORTED);
2185 if (tp != NULL)
2186 INP_WUNLOCK(inp);
2187 } else
2188 INP_WUNLOCK(inp);
2189 } else
2190 error = ESRCH;
2191 INP_INFO_WUNLOCK(&V_tcbinfo);
2192 return (error);
2193 }
2194
2195 SYSCTL_PROC(_net_inet_tcp, TCPCTL_DROP, drop,
2196 CTLTYPE_STRUCT|CTLFLAG_WR|CTLFLAG_SKIP, NULL,
2197 0, sysctl_drop, "", "Drop TCP connection");
2198
2199 /*
2200 * Generate a standardized TCP log line for use throughout the
2201 * tcp subsystem. Memory allocation is done with M_NOWAIT to
2202 * allow use in the interrupt context.
2203 *
2204 * NB: The caller MUST free(s, M_TCPLOG) the returned string.
2205 * NB: The function may return NULL if memory allocation failed.
2206 *
2207 * Due to header inclusion and ordering limitations the struct ip
2208 * and ip6_hdr pointers have to be passed as void pointers.
2209 */
2210 char *
2211 tcp_log_vain(struct in_conninfo *inc, struct tcphdr *th, void *ip4hdr,
2212 const void *ip6hdr)
2213 {
2214
2215 /* Is logging enabled? */
2216 if (tcp_log_in_vain == 0)
2217 return (NULL);
2218
2219 return (tcp_log_addr(inc, th, ip4hdr, ip6hdr));
2220 }
2221
2222 char *
2223 tcp_log_addrs(struct in_conninfo *inc, struct tcphdr *th, void *ip4hdr,
2224 const void *ip6hdr)
2225 {
2226
2227 /* Is logging enabled? */
2228 if (tcp_log_debug == 0)
2229 return (NULL);
2230
2231 return (tcp_log_addr(inc, th, ip4hdr, ip6hdr));
2232 }
2233
2234 static char *
2235 tcp_log_addr(struct in_conninfo *inc, struct tcphdr *th, void *ip4hdr,
2236 const void *ip6hdr)
2237 {
2238 char *s, *sp;
2239 size_t size;
2240 struct ip *ip;
2241 #ifdef INET6
2242 const struct ip6_hdr *ip6;
2243
2244 ip6 = (const struct ip6_hdr *)ip6hdr;
2245 #endif /* INET6 */
2246 ip = (struct ip *)ip4hdr;
2247
2248 /*
2249 * The log line looks like this:
2250 * "TCP: [1.2.3.4]:50332 to [1.2.3.4]:80 tcpflags 0x2<SYN>"
2251 */
2252 size = sizeof("TCP: []:12345 to []:12345 tcpflags 0x2<>") +
2253 sizeof(PRINT_TH_FLAGS) + 1 +
2254 #ifdef INET6
2255 2 * INET6_ADDRSTRLEN;
2256 #else
2257 2 * INET_ADDRSTRLEN;
2258 #endif /* INET6 */
2259
2260 s = malloc(size, M_TCPLOG, M_ZERO|M_NOWAIT);
2261 if (s == NULL)
2262 return (NULL);
2263
2264 strcat(s, "TCP: [");
2265 sp = s + strlen(s);
2266
2267 if (inc && ((inc->inc_flags & INC_ISIPV6) == 0)) {
2268 inet_ntoa_r(inc->inc_faddr, sp);
2269 sp = s + strlen(s);
2270 sprintf(sp, "]:%i to [", ntohs(inc->inc_fport));
2271 sp = s + strlen(s);
2272 inet_ntoa_r(inc->inc_laddr, sp);
2273 sp = s + strlen(s);
2274 sprintf(sp, "]:%i", ntohs(inc->inc_lport));
2275 #ifdef INET6
2276 } else if (inc) {
2277 ip6_sprintf(sp, &inc->inc6_faddr);
2278 sp = s + strlen(s);
2279 sprintf(sp, "]:%i to [", ntohs(inc->inc_fport));
2280 sp = s + strlen(s);
2281 ip6_sprintf(sp, &inc->inc6_laddr);
2282 sp = s + strlen(s);
2283 sprintf(sp, "]:%i", ntohs(inc->inc_lport));
2284 } else if (ip6 && th) {
2285 ip6_sprintf(sp, &ip6->ip6_src);
2286 sp = s + strlen(s);
2287 sprintf(sp, "]:%i to [", ntohs(th->th_sport));
2288 sp = s + strlen(s);
2289 ip6_sprintf(sp, &ip6->ip6_dst);
2290 sp = s + strlen(s);
2291 sprintf(sp, "]:%i", ntohs(th->th_dport));
2292 #endif /* INET6 */
2293 #ifdef INET
2294 } else if (ip && th) {
2295 inet_ntoa_r(ip->ip_src, sp);
2296 sp = s + strlen(s);
2297 sprintf(sp, "]:%i to [", ntohs(th->th_sport));
2298 sp = s + strlen(s);
2299 inet_ntoa_r(ip->ip_dst, sp);
2300 sp = s + strlen(s);
2301 sprintf(sp, "]:%i", ntohs(th->th_dport));
2302 #endif /* INET */
2303 } else {
2304 free(s, M_TCPLOG);
2305 return (NULL);
2306 }
2307 sp = s + strlen(s);
2308 if (th)
2309 sprintf(sp, " tcpflags 0x%b", th->th_flags, PRINT_TH_FLAGS);
2310 if (*(s + size - 1) != '\0')
2311 panic("%s: string too long", __func__);
2312 return (s);
2313 }
Cache object: 16953bcd42dea530f68fd873503dd995
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