1 /*-
2 * Copyright (c) 1982, 1986, 1988, 1990, 1993
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 * @(#)ip_output.c 8.3 (Berkeley) 1/21/94
30 */
31
32 #include <sys/cdefs.h>
33 __FBSDID("$FreeBSD: releng/10.1/sys/netinet/ip_output.c 268956 2014-07-21 20:38:21Z np $");
34
35 #include "opt_inet.h"
36 #include "opt_ipfw.h"
37 #include "opt_ipsec.h"
38 #include "opt_kdtrace.h"
39 #include "opt_mbuf_stress_test.h"
40 #include "opt_mpath.h"
41 #include "opt_route.h"
42 #include "opt_sctp.h"
43
44 #include <sys/param.h>
45 #include <sys/systm.h>
46 #include <sys/kernel.h>
47 #include <sys/malloc.h>
48 #include <sys/mbuf.h>
49 #include <sys/priv.h>
50 #include <sys/proc.h>
51 #include <sys/protosw.h>
52 #include <sys/sdt.h>
53 #include <sys/socket.h>
54 #include <sys/socketvar.h>
55 #include <sys/sysctl.h>
56 #include <sys/ucred.h>
57
58 #include <net/if.h>
59 #include <net/if_llatbl.h>
60 #include <net/netisr.h>
61 #include <net/pfil.h>
62 #include <net/route.h>
63 #include <net/flowtable.h>
64 #ifdef RADIX_MPATH
65 #include <net/radix_mpath.h>
66 #endif
67 #include <net/vnet.h>
68
69 #include <netinet/in.h>
70 #include <netinet/in_kdtrace.h>
71 #include <netinet/in_systm.h>
72 #include <netinet/ip.h>
73 #include <netinet/in_pcb.h>
74 #include <netinet/in_var.h>
75 #include <netinet/ip_var.h>
76 #include <netinet/ip_options.h>
77 #ifdef SCTP
78 #include <netinet/sctp.h>
79 #include <netinet/sctp_crc32.h>
80 #endif
81
82 #ifdef IPSEC
83 #include <netinet/ip_ipsec.h>
84 #include <netipsec/ipsec.h>
85 #endif /* IPSEC*/
86
87 #include <machine/in_cksum.h>
88
89 #include <security/mac/mac_framework.h>
90
91 VNET_DEFINE(u_short, ip_id);
92
93 #ifdef MBUF_STRESS_TEST
94 static int mbuf_frag_size = 0;
95 SYSCTL_INT(_net_inet_ip, OID_AUTO, mbuf_frag_size, CTLFLAG_RW,
96 &mbuf_frag_size, 0, "Fragment outgoing mbufs to this size");
97 #endif
98
99 static void ip_mloopback
100 (struct ifnet *, struct mbuf *, struct sockaddr_in *, int);
101
102
103 extern int in_mcast_loop;
104 extern struct protosw inetsw[];
105
106 /*
107 * IP output. The packet in mbuf chain m contains a skeletal IP
108 * header (with len, off, ttl, proto, tos, src, dst).
109 * The mbuf chain containing the packet will be freed.
110 * The mbuf opt, if present, will not be freed.
111 * If route ro is present and has ro_rt initialized, route lookup would be
112 * skipped and ro->ro_rt would be used. If ro is present but ro->ro_rt is NULL,
113 * then result of route lookup is stored in ro->ro_rt.
114 *
115 * In the IP forwarding case, the packet will arrive with options already
116 * inserted, so must have a NULL opt pointer.
117 */
118 int
119 ip_output(struct mbuf *m, struct mbuf *opt, struct route *ro, int flags,
120 struct ip_moptions *imo, struct inpcb *inp)
121 {
122 struct ip *ip;
123 struct ifnet *ifp = NULL; /* keep compiler happy */
124 struct mbuf *m0;
125 int hlen = sizeof (struct ip);
126 int mtu;
127 int n; /* scratchpad */
128 int error = 0;
129 struct sockaddr_in *dst;
130 const struct sockaddr_in *gw;
131 struct in_ifaddr *ia;
132 int isbroadcast;
133 uint16_t ip_len, ip_off;
134 struct route iproute;
135 struct rtentry *rte; /* cache for ro->ro_rt */
136 struct in_addr odst;
137 struct m_tag *fwd_tag = NULL;
138 int have_ia_ref;
139 #ifdef IPSEC
140 int no_route_but_check_spd = 0;
141 #endif
142 M_ASSERTPKTHDR(m);
143
144 if (inp != NULL) {
145 INP_LOCK_ASSERT(inp);
146 M_SETFIB(m, inp->inp_inc.inc_fibnum);
147 if (inp->inp_flags & (INP_HW_FLOWID|INP_SW_FLOWID)) {
148 m->m_pkthdr.flowid = inp->inp_flowid;
149 m->m_flags |= M_FLOWID;
150 }
151 }
152
153 if (ro == NULL) {
154 ro = &iproute;
155 bzero(ro, sizeof (*ro));
156 }
157
158 #ifdef FLOWTABLE
159 if (ro->ro_rt == NULL)
160 (void )flowtable_lookup(AF_INET, m, ro);
161 #endif
162
163 if (opt) {
164 int len = 0;
165 m = ip_insertoptions(m, opt, &len);
166 if (len != 0)
167 hlen = len; /* ip->ip_hl is updated above */
168 }
169 ip = mtod(m, struct ip *);
170 ip_len = ntohs(ip->ip_len);
171 ip_off = ntohs(ip->ip_off);
172
173 /*
174 * Fill in IP header. If we are not allowing fragmentation,
175 * then the ip_id field is meaningless, but we don't set it
176 * to zero. Doing so causes various problems when devices along
177 * the path (routers, load balancers, firewalls, etc.) illegally
178 * disable DF on our packet. Note that a 16-bit counter
179 * will wrap around in less than 10 seconds at 100 Mbit/s on a
180 * medium with MTU 1500. See Steven M. Bellovin, "A Technique
181 * for Counting NATted Hosts", Proc. IMW'02, available at
182 * <http://www.cs.columbia.edu/~smb/papers/fnat.pdf>.
183 */
184 if ((flags & (IP_FORWARDING|IP_RAWOUTPUT)) == 0) {
185 ip->ip_v = IPVERSION;
186 ip->ip_hl = hlen >> 2;
187 ip->ip_id = ip_newid();
188 IPSTAT_INC(ips_localout);
189 } else {
190 /* Header already set, fetch hlen from there */
191 hlen = ip->ip_hl << 2;
192 }
193
194 /*
195 * dst/gw handling:
196 *
197 * dst can be rewritten but always point to &ro->ro_dst
198 * gw is readonly but can be pointed either to dst OR rt_gatewy
199 * therefore we need restore GW if we're re-doing lookup
200 */
201 gw = dst = (struct sockaddr_in *)&ro->ro_dst;
202 again:
203 ia = NULL;
204 have_ia_ref = 0;
205 /*
206 * If there is a cached route,
207 * check that it is to the same destination
208 * and is still up. If not, free it and try again.
209 * The address family should also be checked in case of sharing the
210 * cache with IPv6.
211 */
212 rte = ro->ro_rt;
213 if (rte && ((rte->rt_flags & RTF_UP) == 0 ||
214 rte->rt_ifp == NULL ||
215 !RT_LINK_IS_UP(rte->rt_ifp) ||
216 dst->sin_family != AF_INET ||
217 dst->sin_addr.s_addr != ip->ip_dst.s_addr)) {
218 RO_RTFREE(ro);
219 ro->ro_lle = NULL;
220 rte = NULL;
221 gw = dst;
222 }
223 if (rte == NULL && fwd_tag == NULL) {
224 bzero(dst, sizeof(*dst));
225 dst->sin_family = AF_INET;
226 dst->sin_len = sizeof(*dst);
227 dst->sin_addr = ip->ip_dst;
228 }
229 /*
230 * If routing to interface only, short circuit routing lookup.
231 * The use of an all-ones broadcast address implies this; an
232 * interface is specified by the broadcast address of an interface,
233 * or the destination address of a ptp interface.
234 */
235 if (flags & IP_SENDONES) {
236 if ((ia = ifatoia(ifa_ifwithbroadaddr(sintosa(dst)))) == NULL &&
237 (ia = ifatoia(ifa_ifwithdstaddr(sintosa(dst)))) == NULL) {
238 IPSTAT_INC(ips_noroute);
239 error = ENETUNREACH;
240 goto bad;
241 }
242 have_ia_ref = 1;
243 ip->ip_dst.s_addr = INADDR_BROADCAST;
244 dst->sin_addr = ip->ip_dst;
245 ifp = ia->ia_ifp;
246 ip->ip_ttl = 1;
247 isbroadcast = 1;
248 } else if (flags & IP_ROUTETOIF) {
249 if ((ia = ifatoia(ifa_ifwithdstaddr(sintosa(dst)))) == NULL &&
250 (ia = ifatoia(ifa_ifwithnet(sintosa(dst), 0))) == NULL) {
251 IPSTAT_INC(ips_noroute);
252 error = ENETUNREACH;
253 goto bad;
254 }
255 have_ia_ref = 1;
256 ifp = ia->ia_ifp;
257 ip->ip_ttl = 1;
258 isbroadcast = in_broadcast(dst->sin_addr, ifp);
259 } else if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr)) &&
260 imo != NULL && imo->imo_multicast_ifp != NULL) {
261 /*
262 * Bypass the normal routing lookup for multicast
263 * packets if the interface is specified.
264 */
265 ifp = imo->imo_multicast_ifp;
266 IFP_TO_IA(ifp, ia);
267 if (ia)
268 have_ia_ref = 1;
269 isbroadcast = 0; /* fool gcc */
270 } else {
271 /*
272 * We want to do any cloning requested by the link layer,
273 * as this is probably required in all cases for correct
274 * operation (as it is for ARP).
275 */
276 if (rte == NULL) {
277 #ifdef RADIX_MPATH
278 rtalloc_mpath_fib(ro,
279 ntohl(ip->ip_src.s_addr ^ ip->ip_dst.s_addr),
280 inp ? inp->inp_inc.inc_fibnum : M_GETFIB(m));
281 #else
282 in_rtalloc_ign(ro, 0,
283 inp ? inp->inp_inc.inc_fibnum : M_GETFIB(m));
284 #endif
285 rte = ro->ro_rt;
286 }
287 if (rte == NULL ||
288 rte->rt_ifp == NULL ||
289 !RT_LINK_IS_UP(rte->rt_ifp)) {
290 #ifdef IPSEC
291 /*
292 * There is no route for this packet, but it is
293 * possible that a matching SPD entry exists.
294 */
295 no_route_but_check_spd = 1;
296 mtu = 0; /* Silence GCC warning. */
297 goto sendit;
298 #endif
299 IPSTAT_INC(ips_noroute);
300 error = EHOSTUNREACH;
301 goto bad;
302 }
303 ia = ifatoia(rte->rt_ifa);
304 ifp = rte->rt_ifp;
305 counter_u64_add(rte->rt_pksent, 1);
306 if (rte->rt_flags & RTF_GATEWAY)
307 gw = (struct sockaddr_in *)rte->rt_gateway;
308 if (rte->rt_flags & RTF_HOST)
309 isbroadcast = (rte->rt_flags & RTF_BROADCAST);
310 else
311 isbroadcast = in_broadcast(gw->sin_addr, ifp);
312 }
313 /*
314 * Calculate MTU. If we have a route that is up, use that,
315 * otherwise use the interface's MTU.
316 */
317 if (rte != NULL && (rte->rt_flags & (RTF_UP|RTF_HOST))) {
318 /*
319 * This case can happen if the user changed the MTU
320 * of an interface after enabling IP on it. Because
321 * most netifs don't keep track of routes pointing to
322 * them, there is no way for one to update all its
323 * routes when the MTU is changed.
324 */
325 if (rte->rt_mtu > ifp->if_mtu)
326 rte->rt_mtu = ifp->if_mtu;
327 mtu = rte->rt_mtu;
328 } else {
329 mtu = ifp->if_mtu;
330 }
331 /* Catch a possible divide by zero later. */
332 KASSERT(mtu > 0, ("%s: mtu %d <= 0, rte=%p (rt_flags=0x%08x) ifp=%p",
333 __func__, mtu, rte, (rte != NULL) ? rte->rt_flags : 0, ifp));
334 if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) {
335 m->m_flags |= M_MCAST;
336 /*
337 * IP destination address is multicast. Make sure "gw"
338 * still points to the address in "ro". (It may have been
339 * changed to point to a gateway address, above.)
340 */
341 gw = dst;
342 /*
343 * See if the caller provided any multicast options
344 */
345 if (imo != NULL) {
346 ip->ip_ttl = imo->imo_multicast_ttl;
347 if (imo->imo_multicast_vif != -1)
348 ip->ip_src.s_addr =
349 ip_mcast_src ?
350 ip_mcast_src(imo->imo_multicast_vif) :
351 INADDR_ANY;
352 } else
353 ip->ip_ttl = IP_DEFAULT_MULTICAST_TTL;
354 /*
355 * Confirm that the outgoing interface supports multicast.
356 */
357 if ((imo == NULL) || (imo->imo_multicast_vif == -1)) {
358 if ((ifp->if_flags & IFF_MULTICAST) == 0) {
359 IPSTAT_INC(ips_noroute);
360 error = ENETUNREACH;
361 goto bad;
362 }
363 }
364 /*
365 * If source address not specified yet, use address
366 * of outgoing interface.
367 */
368 if (ip->ip_src.s_addr == INADDR_ANY) {
369 /* Interface may have no addresses. */
370 if (ia != NULL)
371 ip->ip_src = IA_SIN(ia)->sin_addr;
372 }
373
374 if ((imo == NULL && in_mcast_loop) ||
375 (imo && imo->imo_multicast_loop)) {
376 /*
377 * Loop back multicast datagram if not expressly
378 * forbidden to do so, even if we are not a member
379 * of the group; ip_input() will filter it later,
380 * thus deferring a hash lookup and mutex acquisition
381 * at the expense of a cheap copy using m_copym().
382 */
383 ip_mloopback(ifp, m, dst, hlen);
384 } else {
385 /*
386 * If we are acting as a multicast router, perform
387 * multicast forwarding as if the packet had just
388 * arrived on the interface to which we are about
389 * to send. The multicast forwarding function
390 * recursively calls this function, using the
391 * IP_FORWARDING flag to prevent infinite recursion.
392 *
393 * Multicasts that are looped back by ip_mloopback(),
394 * above, will be forwarded by the ip_input() routine,
395 * if necessary.
396 */
397 if (V_ip_mrouter && (flags & IP_FORWARDING) == 0) {
398 /*
399 * If rsvp daemon is not running, do not
400 * set ip_moptions. This ensures that the packet
401 * is multicast and not just sent down one link
402 * as prescribed by rsvpd.
403 */
404 if (!V_rsvp_on)
405 imo = NULL;
406 if (ip_mforward &&
407 ip_mforward(ip, ifp, m, imo) != 0) {
408 m_freem(m);
409 goto done;
410 }
411 }
412 }
413
414 /*
415 * Multicasts with a time-to-live of zero may be looped-
416 * back, above, but must not be transmitted on a network.
417 * Also, multicasts addressed to the loopback interface
418 * are not sent -- the above call to ip_mloopback() will
419 * loop back a copy. ip_input() will drop the copy if
420 * this host does not belong to the destination group on
421 * the loopback interface.
422 */
423 if (ip->ip_ttl == 0 || ifp->if_flags & IFF_LOOPBACK) {
424 m_freem(m);
425 goto done;
426 }
427
428 goto sendit;
429 }
430
431 /*
432 * If the source address is not specified yet, use the address
433 * of the outoing interface.
434 */
435 if (ip->ip_src.s_addr == INADDR_ANY) {
436 /* Interface may have no addresses. */
437 if (ia != NULL) {
438 ip->ip_src = IA_SIN(ia)->sin_addr;
439 }
440 }
441
442 /*
443 * Verify that we have any chance at all of being able to queue the
444 * packet or packet fragments, unless ALTQ is enabled on the given
445 * interface in which case packetdrop should be done by queueing.
446 */
447 n = ip_len / mtu + 1; /* how many fragments ? */
448 if (
449 #ifdef ALTQ
450 (!ALTQ_IS_ENABLED(&ifp->if_snd)) &&
451 #endif /* ALTQ */
452 (ifp->if_snd.ifq_len + n) >= ifp->if_snd.ifq_maxlen ) {
453 error = ENOBUFS;
454 IPSTAT_INC(ips_odropped);
455 ifp->if_snd.ifq_drops += n;
456 goto bad;
457 }
458
459 /*
460 * Look for broadcast address and
461 * verify user is allowed to send
462 * such a packet.
463 */
464 if (isbroadcast) {
465 if ((ifp->if_flags & IFF_BROADCAST) == 0) {
466 error = EADDRNOTAVAIL;
467 goto bad;
468 }
469 if ((flags & IP_ALLOWBROADCAST) == 0) {
470 error = EACCES;
471 goto bad;
472 }
473 /* don't allow broadcast messages to be fragmented */
474 if (ip_len > mtu) {
475 error = EMSGSIZE;
476 goto bad;
477 }
478 m->m_flags |= M_BCAST;
479 } else {
480 m->m_flags &= ~M_BCAST;
481 }
482
483 sendit:
484 #ifdef IPSEC
485 switch(ip_ipsec_output(&m, inp, &flags, &error)) {
486 case 1:
487 goto bad;
488 case -1:
489 goto done;
490 case 0:
491 default:
492 break; /* Continue with packet processing. */
493 }
494 /*
495 * Check if there was a route for this packet; return error if not.
496 */
497 if (no_route_but_check_spd) {
498 IPSTAT_INC(ips_noroute);
499 error = EHOSTUNREACH;
500 goto bad;
501 }
502 /* Update variables that are affected by ipsec4_output(). */
503 ip = mtod(m, struct ip *);
504 hlen = ip->ip_hl << 2;
505 #endif /* IPSEC */
506
507 /* Jump over all PFIL processing if hooks are not active. */
508 if (!PFIL_HOOKED(&V_inet_pfil_hook))
509 goto passout;
510
511 /* Run through list of hooks for output packets. */
512 odst.s_addr = ip->ip_dst.s_addr;
513 error = pfil_run_hooks(&V_inet_pfil_hook, &m, ifp, PFIL_OUT, inp);
514 if (error != 0 || m == NULL)
515 goto done;
516
517 ip = mtod(m, struct ip *);
518
519 /* See if destination IP address was changed by packet filter. */
520 if (odst.s_addr != ip->ip_dst.s_addr) {
521 m->m_flags |= M_SKIP_FIREWALL;
522 /* If destination is now ourself drop to ip_input(). */
523 if (in_localip(ip->ip_dst)) {
524 m->m_flags |= M_FASTFWD_OURS;
525 if (m->m_pkthdr.rcvif == NULL)
526 m->m_pkthdr.rcvif = V_loif;
527 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
528 m->m_pkthdr.csum_flags |=
529 CSUM_DATA_VALID | CSUM_PSEUDO_HDR;
530 m->m_pkthdr.csum_data = 0xffff;
531 }
532 m->m_pkthdr.csum_flags |=
533 CSUM_IP_CHECKED | CSUM_IP_VALID;
534 #ifdef SCTP
535 if (m->m_pkthdr.csum_flags & CSUM_SCTP)
536 m->m_pkthdr.csum_flags |= CSUM_SCTP_VALID;
537 #endif
538 error = netisr_queue(NETISR_IP, m);
539 goto done;
540 } else {
541 if (have_ia_ref)
542 ifa_free(&ia->ia_ifa);
543 goto again; /* Redo the routing table lookup. */
544 }
545 }
546
547 /* See if local, if yes, send it to netisr with IP_FASTFWD_OURS. */
548 if (m->m_flags & M_FASTFWD_OURS) {
549 if (m->m_pkthdr.rcvif == NULL)
550 m->m_pkthdr.rcvif = V_loif;
551 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
552 m->m_pkthdr.csum_flags |=
553 CSUM_DATA_VALID | CSUM_PSEUDO_HDR;
554 m->m_pkthdr.csum_data = 0xffff;
555 }
556 #ifdef SCTP
557 if (m->m_pkthdr.csum_flags & CSUM_SCTP)
558 m->m_pkthdr.csum_flags |= CSUM_SCTP_VALID;
559 #endif
560 m->m_pkthdr.csum_flags |=
561 CSUM_IP_CHECKED | CSUM_IP_VALID;
562
563 error = netisr_queue(NETISR_IP, m);
564 goto done;
565 }
566 /* Or forward to some other address? */
567 if ((m->m_flags & M_IP_NEXTHOP) &&
568 (fwd_tag = m_tag_find(m, PACKET_TAG_IPFORWARD, NULL)) != NULL) {
569 bcopy((fwd_tag+1), dst, sizeof(struct sockaddr_in));
570 m->m_flags |= M_SKIP_FIREWALL;
571 m->m_flags &= ~M_IP_NEXTHOP;
572 m_tag_delete(m, fwd_tag);
573 if (have_ia_ref)
574 ifa_free(&ia->ia_ifa);
575 goto again;
576 }
577
578 passout:
579 /* 127/8 must not appear on wire - RFC1122. */
580 if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET ||
581 (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) {
582 if ((ifp->if_flags & IFF_LOOPBACK) == 0) {
583 IPSTAT_INC(ips_badaddr);
584 error = EADDRNOTAVAIL;
585 goto bad;
586 }
587 }
588
589 m->m_pkthdr.csum_flags |= CSUM_IP;
590 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA & ~ifp->if_hwassist) {
591 in_delayed_cksum(m);
592 m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
593 }
594 #ifdef SCTP
595 if (m->m_pkthdr.csum_flags & CSUM_SCTP & ~ifp->if_hwassist) {
596 sctp_delayed_cksum(m, (uint32_t)(ip->ip_hl << 2));
597 m->m_pkthdr.csum_flags &= ~CSUM_SCTP;
598 }
599 #endif
600
601 /*
602 * If small enough for interface, or the interface will take
603 * care of the fragmentation for us, we can just send directly.
604 */
605 if (ip_len <= mtu ||
606 (m->m_pkthdr.csum_flags & ifp->if_hwassist & CSUM_TSO) != 0 ||
607 ((ip_off & IP_DF) == 0 && (ifp->if_hwassist & CSUM_FRAGMENT))) {
608 ip->ip_sum = 0;
609 if (m->m_pkthdr.csum_flags & CSUM_IP & ~ifp->if_hwassist) {
610 ip->ip_sum = in_cksum(m, hlen);
611 m->m_pkthdr.csum_flags &= ~CSUM_IP;
612 }
613
614 /*
615 * Record statistics for this interface address.
616 * With CSUM_TSO the byte/packet count will be slightly
617 * incorrect because we count the IP+TCP headers only
618 * once instead of for every generated packet.
619 */
620 if (!(flags & IP_FORWARDING) && ia) {
621 if (m->m_pkthdr.csum_flags & CSUM_TSO)
622 ia->ia_ifa.if_opackets +=
623 m->m_pkthdr.len / m->m_pkthdr.tso_segsz;
624 else
625 ia->ia_ifa.if_opackets++;
626 ia->ia_ifa.if_obytes += m->m_pkthdr.len;
627 }
628 #ifdef MBUF_STRESS_TEST
629 if (mbuf_frag_size && m->m_pkthdr.len > mbuf_frag_size)
630 m = m_fragment(m, M_NOWAIT, mbuf_frag_size);
631 #endif
632 /*
633 * Reset layer specific mbuf flags
634 * to avoid confusing lower layers.
635 */
636 m_clrprotoflags(m);
637 IP_PROBE(send, NULL, NULL, ip, ifp, ip, NULL);
638 error = (*ifp->if_output)(ifp, m,
639 (const struct sockaddr *)gw, ro);
640 goto done;
641 }
642
643 /* Balk when DF bit is set or the interface didn't support TSO. */
644 if ((ip_off & IP_DF) || (m->m_pkthdr.csum_flags & CSUM_TSO)) {
645 error = EMSGSIZE;
646 IPSTAT_INC(ips_cantfrag);
647 goto bad;
648 }
649
650 /*
651 * Too large for interface; fragment if possible. If successful,
652 * on return, m will point to a list of packets to be sent.
653 */
654 error = ip_fragment(ip, &m, mtu, ifp->if_hwassist);
655 if (error)
656 goto bad;
657 for (; m; m = m0) {
658 m0 = m->m_nextpkt;
659 m->m_nextpkt = 0;
660 if (error == 0) {
661 /* Record statistics for this interface address. */
662 if (ia != NULL) {
663 ia->ia_ifa.if_opackets++;
664 ia->ia_ifa.if_obytes += m->m_pkthdr.len;
665 }
666 /*
667 * Reset layer specific mbuf flags
668 * to avoid confusing upper layers.
669 */
670 m_clrprotoflags(m);
671
672 IP_PROBE(send, NULL, NULL, ip, ifp, ip, NULL);
673 error = (*ifp->if_output)(ifp, m,
674 (const struct sockaddr *)gw, ro);
675 } else
676 m_freem(m);
677 }
678
679 if (error == 0)
680 IPSTAT_INC(ips_fragmented);
681
682 done:
683 if (ro == &iproute)
684 RO_RTFREE(ro);
685 if (have_ia_ref)
686 ifa_free(&ia->ia_ifa);
687 return (error);
688 bad:
689 m_freem(m);
690 goto done;
691 }
692
693 /*
694 * Create a chain of fragments which fit the given mtu. m_frag points to the
695 * mbuf to be fragmented; on return it points to the chain with the fragments.
696 * Return 0 if no error. If error, m_frag may contain a partially built
697 * chain of fragments that should be freed by the caller.
698 *
699 * if_hwassist_flags is the hw offload capabilities (see if_data.ifi_hwassist)
700 */
701 int
702 ip_fragment(struct ip *ip, struct mbuf **m_frag, int mtu,
703 u_long if_hwassist_flags)
704 {
705 int error = 0;
706 int hlen = ip->ip_hl << 2;
707 int len = (mtu - hlen) & ~7; /* size of payload in each fragment */
708 int off;
709 struct mbuf *m0 = *m_frag; /* the original packet */
710 int firstlen;
711 struct mbuf **mnext;
712 int nfrags;
713 uint16_t ip_len, ip_off;
714
715 ip_len = ntohs(ip->ip_len);
716 ip_off = ntohs(ip->ip_off);
717
718 if (ip_off & IP_DF) { /* Fragmentation not allowed */
719 IPSTAT_INC(ips_cantfrag);
720 return EMSGSIZE;
721 }
722
723 /*
724 * Must be able to put at least 8 bytes per fragment.
725 */
726 if (len < 8)
727 return EMSGSIZE;
728
729 /*
730 * If the interface will not calculate checksums on
731 * fragmented packets, then do it here.
732 */
733 if (m0->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
734 in_delayed_cksum(m0);
735 m0->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
736 }
737 #ifdef SCTP
738 if (m0->m_pkthdr.csum_flags & CSUM_SCTP) {
739 sctp_delayed_cksum(m0, hlen);
740 m0->m_pkthdr.csum_flags &= ~CSUM_SCTP;
741 }
742 #endif
743 if (len > PAGE_SIZE) {
744 /*
745 * Fragment large datagrams such that each segment
746 * contains a multiple of PAGE_SIZE amount of data,
747 * plus headers. This enables a receiver to perform
748 * page-flipping zero-copy optimizations.
749 *
750 * XXX When does this help given that sender and receiver
751 * could have different page sizes, and also mtu could
752 * be less than the receiver's page size ?
753 */
754 int newlen;
755 struct mbuf *m;
756
757 for (m = m0, off = 0; m && (off+m->m_len) <= mtu; m = m->m_next)
758 off += m->m_len;
759
760 /*
761 * firstlen (off - hlen) must be aligned on an
762 * 8-byte boundary
763 */
764 if (off < hlen)
765 goto smart_frag_failure;
766 off = ((off - hlen) & ~7) + hlen;
767 newlen = (~PAGE_MASK) & mtu;
768 if ((newlen + sizeof (struct ip)) > mtu) {
769 /* we failed, go back the default */
770 smart_frag_failure:
771 newlen = len;
772 off = hlen + len;
773 }
774 len = newlen;
775
776 } else {
777 off = hlen + len;
778 }
779
780 firstlen = off - hlen;
781 mnext = &m0->m_nextpkt; /* pointer to next packet */
782
783 /*
784 * Loop through length of segment after first fragment,
785 * make new header and copy data of each part and link onto chain.
786 * Here, m0 is the original packet, m is the fragment being created.
787 * The fragments are linked off the m_nextpkt of the original
788 * packet, which after processing serves as the first fragment.
789 */
790 for (nfrags = 1; off < ip_len; off += len, nfrags++) {
791 struct ip *mhip; /* ip header on the fragment */
792 struct mbuf *m;
793 int mhlen = sizeof (struct ip);
794
795 m = m_gethdr(M_NOWAIT, MT_DATA);
796 if (m == NULL) {
797 error = ENOBUFS;
798 IPSTAT_INC(ips_odropped);
799 goto done;
800 }
801 m->m_flags |= (m0->m_flags & M_MCAST);
802 /*
803 * In the first mbuf, leave room for the link header, then
804 * copy the original IP header including options. The payload
805 * goes into an additional mbuf chain returned by m_copym().
806 */
807 m->m_data += max_linkhdr;
808 mhip = mtod(m, struct ip *);
809 *mhip = *ip;
810 if (hlen > sizeof (struct ip)) {
811 mhlen = ip_optcopy(ip, mhip) + sizeof (struct ip);
812 mhip->ip_v = IPVERSION;
813 mhip->ip_hl = mhlen >> 2;
814 }
815 m->m_len = mhlen;
816 /* XXX do we need to add ip_off below ? */
817 mhip->ip_off = ((off - hlen) >> 3) + ip_off;
818 if (off + len >= ip_len)
819 len = ip_len - off;
820 else
821 mhip->ip_off |= IP_MF;
822 mhip->ip_len = htons((u_short)(len + mhlen));
823 m->m_next = m_copym(m0, off, len, M_NOWAIT);
824 if (m->m_next == NULL) { /* copy failed */
825 m_free(m);
826 error = ENOBUFS; /* ??? */
827 IPSTAT_INC(ips_odropped);
828 goto done;
829 }
830 m->m_pkthdr.len = mhlen + len;
831 m->m_pkthdr.rcvif = NULL;
832 #ifdef MAC
833 mac_netinet_fragment(m0, m);
834 #endif
835 m->m_pkthdr.csum_flags = m0->m_pkthdr.csum_flags;
836 mhip->ip_off = htons(mhip->ip_off);
837 mhip->ip_sum = 0;
838 if (m->m_pkthdr.csum_flags & CSUM_IP & ~if_hwassist_flags) {
839 mhip->ip_sum = in_cksum(m, mhlen);
840 m->m_pkthdr.csum_flags &= ~CSUM_IP;
841 }
842 *mnext = m;
843 mnext = &m->m_nextpkt;
844 }
845 IPSTAT_ADD(ips_ofragments, nfrags);
846
847 /*
848 * Update first fragment by trimming what's been copied out
849 * and updating header.
850 */
851 m_adj(m0, hlen + firstlen - ip_len);
852 m0->m_pkthdr.len = hlen + firstlen;
853 ip->ip_len = htons((u_short)m0->m_pkthdr.len);
854 ip->ip_off = htons(ip_off | IP_MF);
855 ip->ip_sum = 0;
856 if (m0->m_pkthdr.csum_flags & CSUM_IP & ~if_hwassist_flags) {
857 ip->ip_sum = in_cksum(m0, hlen);
858 m0->m_pkthdr.csum_flags &= ~CSUM_IP;
859 }
860
861 done:
862 *m_frag = m0;
863 return error;
864 }
865
866 void
867 in_delayed_cksum(struct mbuf *m)
868 {
869 struct ip *ip;
870 uint16_t csum, offset, ip_len;
871
872 ip = mtod(m, struct ip *);
873 offset = ip->ip_hl << 2 ;
874 ip_len = ntohs(ip->ip_len);
875 csum = in_cksum_skip(m, ip_len, offset);
876 if (m->m_pkthdr.csum_flags & CSUM_UDP && csum == 0)
877 csum = 0xffff;
878 offset += m->m_pkthdr.csum_data; /* checksum offset */
879
880 /* find the mbuf in the chain where the checksum starts*/
881 while ((m != NULL) && (offset >= m->m_len)) {
882 offset -= m->m_len;
883 m = m->m_next;
884 }
885 KASSERT(m != NULL, ("in_delayed_cksum: checksum outside mbuf chain."));
886 KASSERT(offset + sizeof(u_short) <= m->m_len, ("in_delayed_cksum: checksum split between mbufs."));
887 *(u_short *)(m->m_data + offset) = csum;
888 }
889
890 /*
891 * IP socket option processing.
892 */
893 int
894 ip_ctloutput(struct socket *so, struct sockopt *sopt)
895 {
896 struct inpcb *inp = sotoinpcb(so);
897 int error, optval;
898
899 error = optval = 0;
900 if (sopt->sopt_level != IPPROTO_IP) {
901 error = EINVAL;
902
903 if (sopt->sopt_level == SOL_SOCKET &&
904 sopt->sopt_dir == SOPT_SET) {
905 switch (sopt->sopt_name) {
906 case SO_REUSEADDR:
907 INP_WLOCK(inp);
908 if ((so->so_options & SO_REUSEADDR) != 0)
909 inp->inp_flags2 |= INP_REUSEADDR;
910 else
911 inp->inp_flags2 &= ~INP_REUSEADDR;
912 INP_WUNLOCK(inp);
913 error = 0;
914 break;
915 case SO_REUSEPORT:
916 INP_WLOCK(inp);
917 if ((so->so_options & SO_REUSEPORT) != 0)
918 inp->inp_flags2 |= INP_REUSEPORT;
919 else
920 inp->inp_flags2 &= ~INP_REUSEPORT;
921 INP_WUNLOCK(inp);
922 error = 0;
923 break;
924 case SO_SETFIB:
925 INP_WLOCK(inp);
926 inp->inp_inc.inc_fibnum = so->so_fibnum;
927 INP_WUNLOCK(inp);
928 error = 0;
929 break;
930 default:
931 break;
932 }
933 }
934 return (error);
935 }
936
937 switch (sopt->sopt_dir) {
938 case SOPT_SET:
939 switch (sopt->sopt_name) {
940 case IP_OPTIONS:
941 #ifdef notyet
942 case IP_RETOPTS:
943 #endif
944 {
945 struct mbuf *m;
946 if (sopt->sopt_valsize > MLEN) {
947 error = EMSGSIZE;
948 break;
949 }
950 m = m_get(sopt->sopt_td ? M_WAITOK : M_NOWAIT, MT_DATA);
951 if (m == NULL) {
952 error = ENOBUFS;
953 break;
954 }
955 m->m_len = sopt->sopt_valsize;
956 error = sooptcopyin(sopt, mtod(m, char *), m->m_len,
957 m->m_len);
958 if (error) {
959 m_free(m);
960 break;
961 }
962 INP_WLOCK(inp);
963 error = ip_pcbopts(inp, sopt->sopt_name, m);
964 INP_WUNLOCK(inp);
965 return (error);
966 }
967
968 case IP_BINDANY:
969 if (sopt->sopt_td != NULL) {
970 error = priv_check(sopt->sopt_td,
971 PRIV_NETINET_BINDANY);
972 if (error)
973 break;
974 }
975 /* FALLTHROUGH */
976 case IP_TOS:
977 case IP_TTL:
978 case IP_MINTTL:
979 case IP_RECVOPTS:
980 case IP_RECVRETOPTS:
981 case IP_RECVDSTADDR:
982 case IP_RECVTTL:
983 case IP_RECVIF:
984 case IP_FAITH:
985 case IP_ONESBCAST:
986 case IP_DONTFRAG:
987 case IP_RECVTOS:
988 error = sooptcopyin(sopt, &optval, sizeof optval,
989 sizeof optval);
990 if (error)
991 break;
992
993 switch (sopt->sopt_name) {
994 case IP_TOS:
995 inp->inp_ip_tos = optval;
996 break;
997
998 case IP_TTL:
999 inp->inp_ip_ttl = optval;
1000 break;
1001
1002 case IP_MINTTL:
1003 if (optval >= 0 && optval <= MAXTTL)
1004 inp->inp_ip_minttl = optval;
1005 else
1006 error = EINVAL;
1007 break;
1008
1009 #define OPTSET(bit) do { \
1010 INP_WLOCK(inp); \
1011 if (optval) \
1012 inp->inp_flags |= bit; \
1013 else \
1014 inp->inp_flags &= ~bit; \
1015 INP_WUNLOCK(inp); \
1016 } while (0)
1017
1018 case IP_RECVOPTS:
1019 OPTSET(INP_RECVOPTS);
1020 break;
1021
1022 case IP_RECVRETOPTS:
1023 OPTSET(INP_RECVRETOPTS);
1024 break;
1025
1026 case IP_RECVDSTADDR:
1027 OPTSET(INP_RECVDSTADDR);
1028 break;
1029
1030 case IP_RECVTTL:
1031 OPTSET(INP_RECVTTL);
1032 break;
1033
1034 case IP_RECVIF:
1035 OPTSET(INP_RECVIF);
1036 break;
1037
1038 case IP_FAITH:
1039 OPTSET(INP_FAITH);
1040 break;
1041
1042 case IP_ONESBCAST:
1043 OPTSET(INP_ONESBCAST);
1044 break;
1045 case IP_DONTFRAG:
1046 OPTSET(INP_DONTFRAG);
1047 break;
1048 case IP_BINDANY:
1049 OPTSET(INP_BINDANY);
1050 break;
1051 case IP_RECVTOS:
1052 OPTSET(INP_RECVTOS);
1053 break;
1054 }
1055 break;
1056 #undef OPTSET
1057
1058 /*
1059 * Multicast socket options are processed by the in_mcast
1060 * module.
1061 */
1062 case IP_MULTICAST_IF:
1063 case IP_MULTICAST_VIF:
1064 case IP_MULTICAST_TTL:
1065 case IP_MULTICAST_LOOP:
1066 case IP_ADD_MEMBERSHIP:
1067 case IP_DROP_MEMBERSHIP:
1068 case IP_ADD_SOURCE_MEMBERSHIP:
1069 case IP_DROP_SOURCE_MEMBERSHIP:
1070 case IP_BLOCK_SOURCE:
1071 case IP_UNBLOCK_SOURCE:
1072 case IP_MSFILTER:
1073 case MCAST_JOIN_GROUP:
1074 case MCAST_LEAVE_GROUP:
1075 case MCAST_JOIN_SOURCE_GROUP:
1076 case MCAST_LEAVE_SOURCE_GROUP:
1077 case MCAST_BLOCK_SOURCE:
1078 case MCAST_UNBLOCK_SOURCE:
1079 error = inp_setmoptions(inp, sopt);
1080 break;
1081
1082 case IP_PORTRANGE:
1083 error = sooptcopyin(sopt, &optval, sizeof optval,
1084 sizeof optval);
1085 if (error)
1086 break;
1087
1088 INP_WLOCK(inp);
1089 switch (optval) {
1090 case IP_PORTRANGE_DEFAULT:
1091 inp->inp_flags &= ~(INP_LOWPORT);
1092 inp->inp_flags &= ~(INP_HIGHPORT);
1093 break;
1094
1095 case IP_PORTRANGE_HIGH:
1096 inp->inp_flags &= ~(INP_LOWPORT);
1097 inp->inp_flags |= INP_HIGHPORT;
1098 break;
1099
1100 case IP_PORTRANGE_LOW:
1101 inp->inp_flags &= ~(INP_HIGHPORT);
1102 inp->inp_flags |= INP_LOWPORT;
1103 break;
1104
1105 default:
1106 error = EINVAL;
1107 break;
1108 }
1109 INP_WUNLOCK(inp);
1110 break;
1111
1112 #ifdef IPSEC
1113 case IP_IPSEC_POLICY:
1114 {
1115 caddr_t req;
1116 struct mbuf *m;
1117
1118 if ((error = soopt_getm(sopt, &m)) != 0) /* XXX */
1119 break;
1120 if ((error = soopt_mcopyin(sopt, m)) != 0) /* XXX */
1121 break;
1122 req = mtod(m, caddr_t);
1123 error = ipsec_set_policy(inp, sopt->sopt_name, req,
1124 m->m_len, (sopt->sopt_td != NULL) ?
1125 sopt->sopt_td->td_ucred : NULL);
1126 m_freem(m);
1127 break;
1128 }
1129 #endif /* IPSEC */
1130
1131 default:
1132 error = ENOPROTOOPT;
1133 break;
1134 }
1135 break;
1136
1137 case SOPT_GET:
1138 switch (sopt->sopt_name) {
1139 case IP_OPTIONS:
1140 case IP_RETOPTS:
1141 if (inp->inp_options)
1142 error = sooptcopyout(sopt,
1143 mtod(inp->inp_options,
1144 char *),
1145 inp->inp_options->m_len);
1146 else
1147 sopt->sopt_valsize = 0;
1148 break;
1149
1150 case IP_TOS:
1151 case IP_TTL:
1152 case IP_MINTTL:
1153 case IP_RECVOPTS:
1154 case IP_RECVRETOPTS:
1155 case IP_RECVDSTADDR:
1156 case IP_RECVTTL:
1157 case IP_RECVIF:
1158 case IP_PORTRANGE:
1159 case IP_FAITH:
1160 case IP_ONESBCAST:
1161 case IP_DONTFRAG:
1162 case IP_BINDANY:
1163 case IP_RECVTOS:
1164 switch (sopt->sopt_name) {
1165
1166 case IP_TOS:
1167 optval = inp->inp_ip_tos;
1168 break;
1169
1170 case IP_TTL:
1171 optval = inp->inp_ip_ttl;
1172 break;
1173
1174 case IP_MINTTL:
1175 optval = inp->inp_ip_minttl;
1176 break;
1177
1178 #define OPTBIT(bit) (inp->inp_flags & bit ? 1 : 0)
1179
1180 case IP_RECVOPTS:
1181 optval = OPTBIT(INP_RECVOPTS);
1182 break;
1183
1184 case IP_RECVRETOPTS:
1185 optval = OPTBIT(INP_RECVRETOPTS);
1186 break;
1187
1188 case IP_RECVDSTADDR:
1189 optval = OPTBIT(INP_RECVDSTADDR);
1190 break;
1191
1192 case IP_RECVTTL:
1193 optval = OPTBIT(INP_RECVTTL);
1194 break;
1195
1196 case IP_RECVIF:
1197 optval = OPTBIT(INP_RECVIF);
1198 break;
1199
1200 case IP_PORTRANGE:
1201 if (inp->inp_flags & INP_HIGHPORT)
1202 optval = IP_PORTRANGE_HIGH;
1203 else if (inp->inp_flags & INP_LOWPORT)
1204 optval = IP_PORTRANGE_LOW;
1205 else
1206 optval = 0;
1207 break;
1208
1209 case IP_FAITH:
1210 optval = OPTBIT(INP_FAITH);
1211 break;
1212
1213 case IP_ONESBCAST:
1214 optval = OPTBIT(INP_ONESBCAST);
1215 break;
1216 case IP_DONTFRAG:
1217 optval = OPTBIT(INP_DONTFRAG);
1218 break;
1219 case IP_BINDANY:
1220 optval = OPTBIT(INP_BINDANY);
1221 break;
1222 case IP_RECVTOS:
1223 optval = OPTBIT(INP_RECVTOS);
1224 break;
1225 }
1226 error = sooptcopyout(sopt, &optval, sizeof optval);
1227 break;
1228
1229 /*
1230 * Multicast socket options are processed by the in_mcast
1231 * module.
1232 */
1233 case IP_MULTICAST_IF:
1234 case IP_MULTICAST_VIF:
1235 case IP_MULTICAST_TTL:
1236 case IP_MULTICAST_LOOP:
1237 case IP_MSFILTER:
1238 error = inp_getmoptions(inp, sopt);
1239 break;
1240
1241 #ifdef IPSEC
1242 case IP_IPSEC_POLICY:
1243 {
1244 struct mbuf *m = NULL;
1245 caddr_t req = NULL;
1246 size_t len = 0;
1247
1248 if (m != 0) {
1249 req = mtod(m, caddr_t);
1250 len = m->m_len;
1251 }
1252 error = ipsec_get_policy(sotoinpcb(so), req, len, &m);
1253 if (error == 0)
1254 error = soopt_mcopyout(sopt, m); /* XXX */
1255 if (error == 0)
1256 m_freem(m);
1257 break;
1258 }
1259 #endif /* IPSEC */
1260
1261 default:
1262 error = ENOPROTOOPT;
1263 break;
1264 }
1265 break;
1266 }
1267 return (error);
1268 }
1269
1270 /*
1271 * Routine called from ip_output() to loop back a copy of an IP multicast
1272 * packet to the input queue of a specified interface. Note that this
1273 * calls the output routine of the loopback "driver", but with an interface
1274 * pointer that might NOT be a loopback interface -- evil, but easier than
1275 * replicating that code here.
1276 */
1277 static void
1278 ip_mloopback(struct ifnet *ifp, struct mbuf *m, struct sockaddr_in *dst,
1279 int hlen)
1280 {
1281 register struct ip *ip;
1282 struct mbuf *copym;
1283
1284 /*
1285 * Make a deep copy of the packet because we're going to
1286 * modify the pack in order to generate checksums.
1287 */
1288 copym = m_dup(m, M_NOWAIT);
1289 if (copym != NULL && (copym->m_flags & M_EXT || copym->m_len < hlen))
1290 copym = m_pullup(copym, hlen);
1291 if (copym != NULL) {
1292 /* If needed, compute the checksum and mark it as valid. */
1293 if (copym->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
1294 in_delayed_cksum(copym);
1295 copym->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
1296 copym->m_pkthdr.csum_flags |=
1297 CSUM_DATA_VALID | CSUM_PSEUDO_HDR;
1298 copym->m_pkthdr.csum_data = 0xffff;
1299 }
1300 /*
1301 * We don't bother to fragment if the IP length is greater
1302 * than the interface's MTU. Can this possibly matter?
1303 */
1304 ip = mtod(copym, struct ip *);
1305 ip->ip_sum = 0;
1306 ip->ip_sum = in_cksum(copym, hlen);
1307 #if 1 /* XXX */
1308 if (dst->sin_family != AF_INET) {
1309 printf("ip_mloopback: bad address family %d\n",
1310 dst->sin_family);
1311 dst->sin_family = AF_INET;
1312 }
1313 #endif
1314 if_simloop(ifp, copym, dst->sin_family, 0);
1315 }
1316 }
Cache object: 17ca5a080630b42aa9a76241be2675bd
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