1 /*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1982, 1986, 1988, 1993
5 * The Regents of the University of California. All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of the University nor the names of its contributors
16 * may be used to endorse or promote products derived from this software
17 * without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32 #include "opt_inet.h"
33 #include "opt_inet6.h"
34 #include "opt_sctp.h"
35
36 #include <sys/param.h>
37 #include <sys/ck.h>
38 #include <sys/eventhandler.h>
39 #include <sys/hash.h>
40 #include <sys/kernel.h>
41 #include <sys/lock.h>
42 #include <sys/malloc.h>
43 #include <sys/mbuf.h>
44 #include <sys/module.h>
45 #include <sys/kernel.h>
46 #include <sys/priv.h>
47 #include <sys/proc.h>
48 #include <sys/domain.h>
49 #include <sys/protosw.h>
50 #include <sys/socket.h>
51 #include <sys/socketvar.h>
52 #include <sys/sysctl.h>
53
54 #include <machine/atomic.h>
55
56 #include <net/if.h>
57 #include <net/if_var.h>
58 #include <net/if_private.h>
59 #include <net/netisr.h>
60 #include <net/vnet.h>
61
62 #include <netinet/in.h>
63 #include <netinet/in_pcb.h>
64 #include <netinet/in_systm.h>
65 #include <netinet/in_var.h>
66 #include <netinet/ip.h>
67 #include <netinet/ip_var.h>
68 #include <netinet/ip_divert.h>
69 #ifdef INET6
70 #include <netinet/ip6.h>
71 #include <netinet6/ip6_var.h>
72 #endif
73 #if defined(SCTP) || defined(SCTP_SUPPORT)
74 #include <netinet/sctp_crc32.h>
75 #endif
76
77 #include <security/mac/mac_framework.h>
78 /*
79 * Divert sockets
80 */
81
82 /*
83 * Allocate enough space to hold a full IP packet
84 */
85 #define DIVSNDQ (65536 + 100)
86 #define DIVRCVQ (65536 + 100)
87
88 /*
89 * Usually a system has very few divert ports. Previous implementation
90 * used a linked list.
91 */
92 #define DIVHASHSIZE (1 << 3) /* 8 entries, one cache line. */
93 #define DIVHASH(port) (port % DIVHASHSIZE)
94 #define DCBHASH(dcb) (DIVHASH((dcb)->dcb_port))
95
96 /*
97 * Divert sockets work in conjunction with ipfw or other packet filters,
98 * see the divert(4) manpage for features.
99 * Packets are selected by the packet filter and tagged with an
100 * MTAG_IPFW_RULE tag carrying the 'divert port' number (as set by
101 * the packet filter) and information on the matching filter rule for
102 * subsequent reinjection. The divert_port is used to put the packet
103 * on the corresponding divert socket, while the rule number is passed
104 * up (at least partially) as the sin_port in the struct sockaddr.
105 *
106 * Packets written to the divert socket carry in sin_addr a
107 * destination address, and in sin_port the number of the filter rule
108 * after which to continue processing.
109 * If the destination address is INADDR_ANY, the packet is treated as
110 * as outgoing and sent to ip_output(); otherwise it is treated as
111 * incoming and sent to ip_input().
112 * Further, sin_zero carries some information on the interface,
113 * which can be used in the reinject -- see comments in the code.
114 *
115 * On reinjection, processing in ip_input() and ip_output()
116 * will be exactly the same as for the original packet, except that
117 * packet filter processing will start at the rule number after the one
118 * written in the sin_port (ipfw does not allow a rule #0, so sin_port=0
119 * will apply the entire ruleset to the packet).
120 */
121 static SYSCTL_NODE(_net_inet, OID_AUTO, divert, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
122 "divert(4)");
123
124 VNET_PCPUSTAT_DEFINE_STATIC(struct divstat, divstat);
125 VNET_PCPUSTAT_SYSINIT(divstat);
126 #ifdef VIMAGE
127 VNET_PCPUSTAT_SYSUNINIT(divstat);
128 #endif
129 SYSCTL_VNET_PCPUSTAT(_net_inet_divert, OID_AUTO, stats, struct divstat,
130 divstat, "divert(4) socket statistics");
131 #define DIVSTAT_INC(name) \
132 VNET_PCPUSTAT_ADD(struct divstat, divstat, div_ ## name, 1)
133
134 static u_long div_sendspace = DIVSNDQ; /* XXX sysctl ? */
135 static u_long div_recvspace = DIVRCVQ; /* XXX sysctl ? */
136
137 static int div_output_inbound(int fmaily, struct socket *so, struct mbuf *m,
138 struct sockaddr_in *sin);
139 static int div_output_outbound(int family, struct socket *so, struct mbuf *m);
140
141 struct divcb {
142 union {
143 CK_SLIST_ENTRY(divcb) dcb_next;
144 intptr_t dcb_bound;
145 #define DCB_UNBOUND ((intptr_t)-1)
146 };
147 struct socket *dcb_socket;
148 uint16_t dcb_port;
149 uint64_t dcb_gencnt;
150 struct epoch_context dcb_epochctx;
151 };
152
153 struct divcblbgroup {
154 CK_SLIST_ENTRY(divcblbgroup) dl_next;
155 struct epoch_context dl_epochctx;
156 uint16_t dl_port;
157 int dl_count;
158 #define DIVCBLBGROUP_SIZE 32
159 struct divcb *dl_dcb[DIVCBLBGROUP_SIZE];
160 };
161
162 CK_SLIST_HEAD(divhashhead, divcb);
163 CK_SLIST_HEAD(divlbgrouphashhead, divcblbgroup);
164
165 VNET_DEFINE_STATIC(struct divhashhead, divhash[DIVHASHSIZE]);
166 #define V_divhash VNET(divhash)
167 VNET_DEFINE_STATIC(struct divlbgrouphashhead, divlbhash[DIVHASHSIZE]);
168 #define V_divlbhash VNET(divlbhash)
169 VNET_DEFINE_STATIC(uint64_t, dcb_count) = 0;
170 #define V_dcb_count VNET(dcb_count)
171 VNET_DEFINE_STATIC(uint64_t, dcb_gencnt) = 0;
172 #define V_dcb_gencnt VNET(dcb_gencnt)
173
174 static struct mtx divert_mtx;
175 MTX_SYSINIT(divert, &divert_mtx, "divert(4) socket pcb lists", MTX_DEF);
176 #define DIVERT_LOCK() mtx_lock(&divert_mtx)
177 #define DIVERT_UNLOCK() mtx_unlock(&divert_mtx)
178
179 /*
180 * Divert a packet by passing it up to the divert socket at port 'port'.
181 *
182 * 'id' is an opaque identifier for the flow and is used to load-balance packets
183 * across multiple divert sockets bound to the same port. Packets with the same
184 * identifier will be delivered to the same socket.
185 */
186 static void
divert_packet(struct mbuf * m,uint64_t id,bool incoming)187 divert_packet(struct mbuf *m, uint64_t id, bool incoming)
188 {
189 struct divcblbgroup *dlb;
190 struct divcb *dcb;
191 u_int16_t nport;
192 struct sockaddr_in divsrc;
193 struct m_tag *mtag;
194 uint16_t cookie;
195
196 NET_EPOCH_ASSERT();
197
198 mtag = m_tag_locate(m, MTAG_IPFW_RULE, 0, NULL);
199 if (mtag != NULL) {
200 cookie = ((struct ipfw_rule_ref *)(mtag+1))->rulenum;
201 nport = htons((uint16_t)
202 (((struct ipfw_rule_ref *)(mtag+1))->info));
203 } else if ((mtag = m_tag_locate(m, MTAG_PF_DIVERT, 0, NULL)) != NULL) {
204 cookie = ((struct pf_divert_mtag *)(mtag+1))->idir;
205 nport = htons(((struct pf_divert_mtag *)(mtag+1))->port);
206 } else {
207 m_freem(m);
208 return;
209 }
210 /* Assure header */
211 if (m->m_len < sizeof(struct ip) &&
212 (m = m_pullup(m, sizeof(struct ip))) == NULL)
213 return;
214 #ifdef INET
215 /* Delayed checksums are currently not compatible with divert. */
216 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
217 in_delayed_cksum(m);
218 m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
219 }
220 #if defined(SCTP) || defined(SCTP_SUPPORT)
221 if (m->m_pkthdr.csum_flags & CSUM_SCTP) {
222 struct ip *ip;
223
224 ip = mtod(m, struct ip *);
225 sctp_delayed_cksum(m, (uint32_t)(ip->ip_hl << 2));
226 m->m_pkthdr.csum_flags &= ~CSUM_SCTP;
227 }
228 #endif
229 #endif
230 #ifdef INET6
231 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA_IPV6) {
232 in6_delayed_cksum(m, m->m_pkthdr.len -
233 sizeof(struct ip6_hdr), sizeof(struct ip6_hdr));
234 m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA_IPV6;
235 }
236 #if defined(SCTP) || defined(SCTP_SUPPORT)
237 if (m->m_pkthdr.csum_flags & CSUM_SCTP_IPV6) {
238 sctp_delayed_cksum(m, sizeof(struct ip6_hdr));
239 m->m_pkthdr.csum_flags &= ~CSUM_SCTP_IPV6;
240 }
241 #endif
242 #endif /* INET6 */
243 bzero(&divsrc, sizeof(divsrc));
244 divsrc.sin_len = sizeof(divsrc);
245 divsrc.sin_family = AF_INET;
246 /* record matching rule, in host format */
247 divsrc.sin_port = cookie;
248 /*
249 * Record receive interface address, if any.
250 * But only for incoming packets.
251 */
252 if (incoming) {
253 struct ifaddr *ifa;
254 struct ifnet *ifp;
255
256 /* Sanity check */
257 M_ASSERTPKTHDR(m);
258
259 /* Find IP address for receive interface */
260 ifp = m->m_pkthdr.rcvif;
261 CK_STAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
262 if (ifa->ifa_addr->sa_family != AF_INET)
263 continue;
264 divsrc.sin_addr =
265 ((struct sockaddr_in *) ifa->ifa_addr)->sin_addr;
266 break;
267 }
268 }
269 /*
270 * Record the incoming interface name whenever we have one.
271 */
272 if (m->m_pkthdr.rcvif) {
273 /*
274 * Hide the actual interface name in there in the
275 * sin_zero array. XXX This needs to be moved to a
276 * different sockaddr type for divert, e.g.
277 * sockaddr_div with multiple fields like
278 * sockaddr_dl. Presently we have only 7 bytes
279 * but that will do for now as most interfaces
280 * are 4 or less + 2 or less bytes for unit.
281 * There is probably a faster way of doing this,
282 * possibly taking it from the sockaddr_dl on the iface.
283 * This solves the problem of a P2P link and a LAN interface
284 * having the same address, which can result in the wrong
285 * interface being assigned to the packet when fed back
286 * into the divert socket. Theoretically if the daemon saves
287 * and re-uses the sockaddr_in as suggested in the man pages,
288 * this iface name will come along for the ride.
289 * (see div_output for the other half of this.)
290 */
291 strlcpy(divsrc.sin_zero, m->m_pkthdr.rcvif->if_xname,
292 sizeof(divsrc.sin_zero));
293 }
294
295 /*
296 * Look for a matching divert socket or socket group, and enqueue the
297 * packet.
298 */
299 CK_SLIST_FOREACH(dlb, &V_divlbhash[DIVHASH(nport)], dl_next) {
300 uint16_t count;
301
302 count = atomic_load_acq_int(&dlb->dl_count);
303 if (dlb->dl_port == nport && count > 0) {
304 uint32_t hash;
305
306 hash = jenkins_hash(&id, sizeof(uint64_t), 0);
307 dcb = dlb->dl_dcb[hash % count];
308 break;
309 }
310 }
311 if (dlb == NULL) {
312 CK_SLIST_FOREACH(dcb, &V_divhash[DIVHASH(nport)], dcb_next)
313 if (dcb->dcb_port == nport)
314 break;
315 }
316
317 if (dcb != NULL) {
318 struct socket *sa = dcb->dcb_socket;
319
320 SOCKBUF_LOCK(&sa->so_rcv);
321 if (sbappendaddr_locked(&sa->so_rcv,
322 (struct sockaddr *)&divsrc, m, NULL) == 0) {
323 soroverflow_locked(sa);
324 m_freem(m);
325 } else {
326 sorwakeup_locked(sa);
327 DIVSTAT_INC(diverted);
328 }
329 } else {
330 DIVSTAT_INC(noport);
331 m_freem(m);
332 }
333 }
334
335 /*
336 * Deliver packet back into the IP processing machinery.
337 *
338 * If no address specified, or address is 0.0.0.0, send to ip_output();
339 * otherwise, send to ip_input() and mark as having been received on
340 * the interface with that address.
341 */
342 static int
div_send(struct socket * so,int flags,struct mbuf * m,struct sockaddr * nam,struct mbuf * control,struct thread * td)343 div_send(struct socket *so, int flags, struct mbuf *m, struct sockaddr *nam,
344 struct mbuf *control, struct thread *td)
345 {
346 struct epoch_tracker et;
347 struct sockaddr_in *sin = (struct sockaddr_in *)nam;
348 const struct ip *ip;
349 struct m_tag *mtag;
350 struct ipfw_rule_ref *dt;
351 struct pf_divert_mtag *pfdt;
352 int error, family;
353
354 if (control)
355 m_freem(control);
356
357 /* Packet must have a header (but that's about it) */
358 if (m->m_len < sizeof (struct ip) &&
359 (m = m_pullup(m, sizeof (struct ip))) == NULL) {
360 m_freem(m);
361 return (EINVAL);
362 }
363
364 if (sin != NULL) {
365 if (sin->sin_family != AF_INET) {
366 m_freem(m);
367 return (EAFNOSUPPORT);
368 }
369 if (sin->sin_len != sizeof(*sin)) {
370 m_freem(m);
371 return (EINVAL);
372 }
373 }
374
375 /*
376 * An mbuf may hasn't come from userland, but we pretend
377 * that it has.
378 */
379 m->m_pkthdr.rcvif = NULL;
380 m->m_nextpkt = NULL;
381 M_SETFIB(m, so->so_fibnum);
382
383 mtag = m_tag_locate(m, MTAG_IPFW_RULE, 0, NULL);
384 if (mtag == NULL) {
385 /* this should be normal */
386 mtag = m_tag_alloc(MTAG_IPFW_RULE, 0,
387 sizeof(struct ipfw_rule_ref), M_NOWAIT | M_ZERO);
388 if (mtag == NULL) {
389 m_freem(m);
390 return (ENOBUFS);
391 }
392 m_tag_prepend(m, mtag);
393 }
394 dt = (struct ipfw_rule_ref *)(mtag+1);
395
396 /* Loopback avoidance and state recovery */
397 if (sin) {
398 int i;
399
400 /* set the starting point. We provide a non-zero slot,
401 * but a non_matching chain_id to skip that info and use
402 * the rulenum/rule_id.
403 */
404 dt->slot = 1; /* dummy, chain_id is invalid */
405 dt->chain_id = 0;
406 dt->rulenum = sin->sin_port+1; /* host format ? */
407 dt->rule_id = 0;
408 /* XXX: broken for IPv6 */
409 /*
410 * Find receive interface with the given name, stuffed
411 * (if it exists) in the sin_zero[] field.
412 * The name is user supplied data so don't trust its size
413 * or that it is zero terminated.
414 */
415 for (i = 0; i < sizeof(sin->sin_zero) && sin->sin_zero[i]; i++)
416 ;
417 if ( i > 0 && i < sizeof(sin->sin_zero))
418 m->m_pkthdr.rcvif = ifunit(sin->sin_zero);
419 }
420
421 ip = mtod(m, struct ip *);
422 switch (ip->ip_v) {
423 #ifdef INET
424 case IPVERSION:
425 family = AF_INET;
426 break;
427 #endif
428 #ifdef INET6
429 case IPV6_VERSION >> 4:
430 family = AF_INET6;
431 break;
432 #endif
433 default:
434 m_freem(m);
435 return (EAFNOSUPPORT);
436 }
437
438 mtag = m_tag_locate(m, MTAG_PF_DIVERT, 0, NULL);
439 if (mtag == NULL) {
440 /* this should be normal */
441 mtag = m_tag_alloc(MTAG_PF_DIVERT, 0,
442 sizeof(struct pf_divert_mtag), M_NOWAIT | M_ZERO);
443 if (mtag == NULL) {
444 m_freem(m);
445 return (ENOBUFS);
446 }
447 m_tag_prepend(m, mtag);
448 }
449 pfdt = (struct pf_divert_mtag *)(mtag+1);
450 if (sin)
451 pfdt->idir = sin->sin_port;
452
453 /* Reinject packet into the system as incoming or outgoing */
454 NET_EPOCH_ENTER(et);
455 if (!sin || sin->sin_addr.s_addr == 0) {
456 dt->info |= IPFW_IS_DIVERT | IPFW_INFO_OUT;
457 pfdt->ndir = PF_DIVERT_MTAG_DIR_OUT;
458 error = div_output_outbound(family, so, m);
459 } else {
460 dt->info |= IPFW_IS_DIVERT | IPFW_INFO_IN;
461 pfdt->ndir = PF_DIVERT_MTAG_DIR_IN;
462 error = div_output_inbound(family, so, m, sin);
463 }
464 NET_EPOCH_EXIT(et);
465
466 return (error);
467 }
468
469 /*
470 * Sends mbuf @m to the wire via ip[6]_output().
471 *
472 * Returns 0 on success or an errno value on failure. @m is always consumed.
473 */
474 static int
div_output_outbound(int family,struct socket * so,struct mbuf * m)475 div_output_outbound(int family, struct socket *so, struct mbuf *m)
476 {
477 int error;
478
479 switch (family) {
480 #ifdef INET
481 case AF_INET:
482 {
483 struct ip *const ip = mtod(m, struct ip *);
484
485 /* Don't allow packet length sizes that will crash. */
486 if (((u_short)ntohs(ip->ip_len) > m->m_pkthdr.len)) {
487 m_freem(m);
488 return (EINVAL);
489 }
490 break;
491 }
492 #endif
493 #ifdef INET6
494 case AF_INET6:
495 {
496 struct ip6_hdr *const ip6 = mtod(m, struct ip6_hdr *);
497
498 /* Don't allow packet length sizes that will crash */
499 if (((u_short)ntohs(ip6->ip6_plen) > m->m_pkthdr.len)) {
500 m_freem(m);
501 return (EINVAL);
502 }
503 break;
504 }
505 #endif
506 }
507
508 #ifdef MAC
509 mac_socket_create_mbuf(so, m);
510 #endif
511
512 error = 0;
513 switch (family) {
514 #ifdef INET
515 case AF_INET:
516 error = ip_output(m, NULL, NULL,
517 ((so->so_options & SO_DONTROUTE) ? IP_ROUTETOIF : 0)
518 | IP_ALLOWBROADCAST | IP_RAWOUTPUT, NULL, NULL);
519 break;
520 #endif
521 #ifdef INET6
522 case AF_INET6:
523 error = ip6_output(m, NULL, NULL, 0, NULL, NULL, NULL);
524 break;
525 #endif
526 }
527 if (error == 0)
528 DIVSTAT_INC(outbound);
529
530 return (error);
531 }
532
533 /*
534 * Schedules mbuf @m for local processing via IPv4/IPv6 netisr queue.
535 *
536 * Returns 0 on success or an errno value on failure. @m is always consumed.
537 */
538 static int
div_output_inbound(int family,struct socket * so,struct mbuf * m,struct sockaddr_in * sin)539 div_output_inbound(int family, struct socket *so, struct mbuf *m,
540 struct sockaddr_in *sin)
541 {
542 #if defined(INET) || defined(INET6)
543 struct divcb *dcb = so->so_pcb;
544 #endif
545 struct ifaddr *ifa;
546
547 if (m->m_pkthdr.rcvif == NULL) {
548 /*
549 * No luck with the name, check by IP address.
550 * Clear the port and the ifname to make sure
551 * there are no distractions for ifa_ifwithaddr.
552 */
553
554 /* XXX: broken for IPv6 */
555 bzero(sin->sin_zero, sizeof(sin->sin_zero));
556 sin->sin_port = 0;
557 ifa = ifa_ifwithaddr((struct sockaddr *) sin);
558 if (ifa == NULL) {
559 m_freem(m);
560 return (EADDRNOTAVAIL);
561 }
562 m->m_pkthdr.rcvif = ifa->ifa_ifp;
563 }
564 #ifdef MAC
565 mac_socket_create_mbuf(so, m);
566 #endif
567 /* Send packet to input processing via netisr */
568 switch (family) {
569 #ifdef INET
570 case AF_INET:
571 {
572 const struct ip *ip;
573
574 ip = mtod(m, struct ip *);
575 /*
576 * Restore M_BCAST flag when destination address is
577 * broadcast. It is expected by ip_tryforward().
578 */
579 if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr)))
580 m->m_flags |= M_MCAST;
581 else if (in_ifnet_broadcast(ip->ip_dst, m->m_pkthdr.rcvif))
582 m->m_flags |= M_BCAST;
583 netisr_queue_src(NETISR_IP, (uintptr_t)dcb->dcb_gencnt, m);
584 DIVSTAT_INC(inbound);
585 break;
586 }
587 #endif
588 #ifdef INET6
589 case AF_INET6:
590 netisr_queue_src(NETISR_IPV6, (uintptr_t)dcb->dcb_gencnt, m);
591 DIVSTAT_INC(inbound);
592 break;
593 #endif
594 default:
595 m_freem(m);
596 return (EINVAL);
597 }
598
599 return (0);
600 }
601
602 static int
div_attach(struct socket * so,int proto,struct thread * td)603 div_attach(struct socket *so, int proto, struct thread *td)
604 {
605 struct divcb *dcb;
606 int error;
607
608 if (td != NULL) {
609 error = priv_check(td, PRIV_NETINET_DIVERT);
610 if (error)
611 return (error);
612 }
613 error = soreserve(so, div_sendspace, div_recvspace);
614 if (error)
615 return error;
616 dcb = malloc(sizeof(*dcb), M_PCB, M_WAITOK);
617 dcb->dcb_bound = DCB_UNBOUND;
618 dcb->dcb_socket = so;
619 DIVERT_LOCK();
620 V_dcb_count++;
621 dcb->dcb_gencnt = ++V_dcb_gencnt;
622 DIVERT_UNLOCK();
623 so->so_pcb = dcb;
624
625 return (0);
626 }
627
628 static void
div_free(epoch_context_t ctx)629 div_free(epoch_context_t ctx)
630 {
631 struct divcb *dcb = __containerof(ctx, struct divcb, dcb_epochctx);
632
633 free(dcb, M_PCB);
634 }
635
636 static void
divlbgroup_free(epoch_context_t ctx)637 divlbgroup_free(epoch_context_t ctx)
638 {
639 struct divcblbgroup *dlb = __containerof(ctx, struct divcblbgroup,
640 dl_epochctx);
641
642 free(dlb, M_PCB);
643 }
644
645 static void
div_lbgroup_detach(struct divcb * dcb)646 div_lbgroup_detach(struct divcb *dcb)
647 {
648 struct divcblbgroup *dlb;
649
650 CK_SLIST_FOREACH(dlb, &V_divlbhash[DCBHASH(dcb)], dl_next) {
651 if (dlb->dl_port != dcb->dcb_port)
652 continue;
653
654 /*
655 * Delicately remove the socket from its group, taking
656 * care to synchronize with lookups, which do not handle
657 * NULL slots in the group table.
658 *
659 * Note that the hash is not stable across different
660 * group sizes.
661 */
662 for (int i = 0; i < dlb->dl_count; i++) {
663 unsigned int count;
664
665 if (dlb->dl_dcb[i] != dcb)
666 continue;
667
668 count = dlb->dl_count;
669 if (i != count - 1)
670 dlb->dl_dcb[i] = dlb->dl_dcb[count - 1];
671 atomic_store_rel_int(&dlb->dl_count, count - 1);
672 if (count == 1) {
673 CK_SLIST_REMOVE(&V_divlbhash[DCBHASH(dcb)], dlb,
674 divcblbgroup, dl_next);
675 NET_EPOCH_CALL(divlbgroup_free,
676 &dlb->dl_epochctx);
677 }
678 return;
679 }
680 }
681 }
682
683 static void
div_detach(struct socket * so)684 div_detach(struct socket *so)
685 {
686 struct divcb *dcb = so->so_pcb;
687
688 so->so_pcb = NULL;
689 DIVERT_LOCK();
690 if (dcb->dcb_bound != DCB_UNBOUND) {
691 CK_SLIST_REMOVE(&V_divhash[DCBHASH(dcb)], dcb, divcb, dcb_next);
692 div_lbgroup_detach(dcb);
693 }
694 V_dcb_count--;
695 V_dcb_gencnt++;
696 DIVERT_UNLOCK();
697 NET_EPOCH_CALL(div_free, &dcb->dcb_epochctx);
698 }
699
700 static int
div_bind(struct socket * so,struct sockaddr * nam,struct thread * td)701 div_bind(struct socket *so, struct sockaddr *nam, struct thread *td)
702 {
703 struct divcblbgroup *dlb;
704 struct divcb *dcb;
705 int error;
706 uint16_t port;
707
708 if (nam->sa_family != AF_INET)
709 return EAFNOSUPPORT;
710 if (nam->sa_len != sizeof(struct sockaddr_in))
711 return EINVAL;
712
713 error = 0;
714 if ((so->so_options & SO_REUSEPORT_LB) != 0)
715 dlb = malloc(sizeof(*dlb), M_PCB, M_WAITOK | M_ZERO);
716 else
717 dlb = NULL;
718
719 port = ((struct sockaddr_in *)nam)->sin_port;
720 DIVERT_LOCK();
721 if (dlb == NULL) {
722 CK_SLIST_FOREACH(dcb, &V_divhash[DIVHASH(port)], dcb_next) {
723 if (dcb->dcb_port == port) {
724 DIVERT_UNLOCK();
725 return (EADDRINUSE);
726 }
727 }
728 }
729 dcb = so->so_pcb;
730 if (dlb != NULL) {
731 struct divcblbgroup *tmp;
732
733 CK_SLIST_FOREACH(tmp, &V_divlbhash[DIVHASH(port)], dl_next) {
734 if (tmp->dl_port == port)
735 break;
736 }
737 if (tmp == NULL) {
738 dlb->dl_port = port;
739 dlb->dl_count = 1;
740 dlb->dl_dcb[0] = dcb;
741 CK_SLIST_INSERT_HEAD(&V_divlbhash[DIVHASH(port)], dlb,
742 dl_next);
743 } else if (tmp->dl_count < DIVCBLBGROUP_SIZE) {
744 KASSERT(tmp->dl_count > 0,
745 ("div_bind: lbgroup %p has count 0", tmp));
746
747 tmp->dl_dcb[tmp->dl_count] = dcb;
748 atomic_store_rel_int(&tmp->dl_count, tmp->dl_count + 1);
749 free(dlb, M_PCB);
750 } else {
751 error = ENOSPC;
752 free(dlb, M_PCB);
753 }
754 }
755 if (error == 0) {
756 if (dcb->dcb_bound != DCB_UNBOUND) {
757 CK_SLIST_REMOVE(&V_divhash[DCBHASH(dcb)], dcb, divcb,
758 dcb_next);
759 div_lbgroup_detach(dcb);
760 }
761 dcb->dcb_port = port;
762 CK_SLIST_INSERT_HEAD(&V_divhash[DIVHASH(port)], dcb, dcb_next);
763 }
764 DIVERT_UNLOCK();
765
766 return (error);
767 }
768
769 static int
div_pcblist(SYSCTL_HANDLER_ARGS)770 div_pcblist(SYSCTL_HANDLER_ARGS)
771 {
772 struct xinpgen xig;
773 struct divcb *dcb;
774 int error;
775
776 if (req->newptr != 0)
777 return EPERM;
778
779 if (req->oldptr == 0) {
780 u_int n;
781
782 n = V_dcb_count;
783 n += imax(n / 8, 10);
784 req->oldidx = 2 * (sizeof xig) + n * sizeof(struct xinpcb);
785 return 0;
786 }
787
788 if ((error = sysctl_wire_old_buffer(req, 0)) != 0)
789 return (error);
790
791 bzero(&xig, sizeof(xig));
792 xig.xig_len = sizeof xig;
793 xig.xig_count = V_dcb_count;
794 xig.xig_gen = V_dcb_gencnt;
795 xig.xig_sogen = so_gencnt;
796 error = SYSCTL_OUT(req, &xig, sizeof xig);
797 if (error)
798 return error;
799
800 DIVERT_LOCK();
801 for (int i = 0; i < DIVHASHSIZE; i++)
802 CK_SLIST_FOREACH(dcb, &V_divhash[i], dcb_next) {
803 if (dcb->dcb_gencnt <= xig.xig_gen) {
804 struct xinpcb xi;
805
806 bzero(&xi, sizeof(xi));
807 xi.xi_len = sizeof(struct xinpcb);
808 sotoxsocket(dcb->dcb_socket, &xi.xi_socket);
809 xi.inp_gencnt = dcb->dcb_gencnt;
810 xi.inp_vflag = INP_IPV4; /* XXX: netstat(1) */
811 xi.inp_inc.inc_ie.ie_lport = dcb->dcb_port;
812 error = SYSCTL_OUT(req, &xi, sizeof xi);
813 if (error)
814 goto errout;
815 }
816 }
817
818 /*
819 * Give the user an updated idea of our state.
820 * If the generation differs from what we told
821 * her before, she knows that something happened
822 * while we were processing this request, and it
823 * might be necessary to retry.
824 */
825 xig.xig_gen = V_dcb_gencnt;
826 xig.xig_sogen = so_gencnt;
827 xig.xig_count = V_dcb_count;
828 error = SYSCTL_OUT(req, &xig, sizeof xig);
829
830 errout:
831 DIVERT_UNLOCK();
832
833 return (error);
834 }
835 SYSCTL_PROC(_net_inet_divert, OID_AUTO, pcblist,
836 CTLTYPE_OPAQUE | CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, 0, div_pcblist,
837 "S,xinpcb", "List of active divert sockets");
838
839 static struct protosw div_protosw = {
840 .pr_type = SOCK_RAW,
841 .pr_flags = PR_ATOMIC|PR_ADDR,
842 .pr_attach = div_attach,
843 .pr_bind = div_bind,
844 .pr_detach = div_detach,
845 .pr_send = div_send,
846 };
847
848 static struct domain divertdomain = {
849 .dom_family = PF_DIVERT,
850 .dom_name = "divert",
851 .dom_nprotosw = 1,
852 .dom_protosw = { &div_protosw },
853 };
854
855 static int
div_modevent(module_t mod,int type,void * unused)856 div_modevent(module_t mod, int type, void *unused)
857 {
858 int err = 0;
859
860 switch (type) {
861 case MOD_LOAD:
862 domain_add(&divertdomain);
863 ip_divert_ptr = divert_packet;
864 break;
865 case MOD_QUIESCE:
866 /*
867 * IPDIVERT may normally not be unloaded because of the
868 * potential race conditions. Tell kldunload we can't be
869 * unloaded unless the unload is forced.
870 */
871 err = EPERM;
872 break;
873 case MOD_UNLOAD:
874 /*
875 * Forced unload.
876 *
877 * Module ipdivert can only be unloaded if no sockets are
878 * connected. Maybe this can be changed later to forcefully
879 * disconnect any open sockets.
880 *
881 * XXXRW: Note that there is a slight race here, as a new
882 * socket open request could be spinning on the lock and then
883 * we destroy the lock.
884 *
885 * XXXGL: One more reason this code is incorrect is that it
886 * checks only the current vnet.
887 */
888 DIVERT_LOCK();
889 if (V_dcb_count != 0) {
890 DIVERT_UNLOCK();
891 err = EBUSY;
892 break;
893 }
894 DIVERT_UNLOCK();
895 ip_divert_ptr = NULL;
896 domain_remove(&divertdomain);
897 break;
898 default:
899 err = EOPNOTSUPP;
900 break;
901 }
902 return err;
903 }
904
905 static moduledata_t ipdivertmod = {
906 "ipdivert",
907 div_modevent,
908 0
909 };
910
911 DECLARE_MODULE(ipdivert, ipdivertmod, SI_SUB_PROTO_FIREWALL, SI_ORDER_ANY);
912 MODULE_VERSION(ipdivert, 1);
913