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/10.0/sys/netinet/ip_output.c 260378 2014-01-06 19:14:46Z glebius $");
34
35 #include "opt_ipfw.h"
36 #include "opt_ipsec.h"
37 #include "opt_kdtrace.h"
38 #include "opt_mbuf_stress_test.h"
39 #include "opt_mpath.h"
40 #include "opt_route.h"
41 #include "opt_sctp.h"
42
43 #include <sys/param.h>
44 #include <sys/systm.h>
45 #include <sys/kernel.h>
46 #include <sys/malloc.h>
47 #include <sys/mbuf.h>
48 #include <sys/priv.h>
49 #include <sys/proc.h>
50 #include <sys/protosw.h>
51 #include <sys/sdt.h>
52 #include <sys/socket.h>
53 #include <sys/socketvar.h>
54 #include <sys/sysctl.h>
55 #include <sys/ucred.h>
56
57 #include <net/if.h>
58 #include <net/if_llatbl.h>
59 #include <net/netisr.h>
60 #include <net/pfil.h>
61 #include <net/route.h>
62 #include <net/flowtable.h>
63 #ifdef RADIX_MPATH
64 #include <net/radix_mpath.h>
65 #endif
66 #include <net/vnet.h>
67
68 #include <netinet/in.h>
69 #include <netinet/in_kdtrace.h>
70 #include <netinet/in_systm.h>
71 #include <netinet/ip.h>
72 #include <netinet/in_pcb.h>
73 #include <netinet/in_var.h>
74 #include <netinet/ip_var.h>
75 #include <netinet/ip_options.h>
76 #ifdef SCTP
77 #include <netinet/sctp.h>
78 #include <netinet/sctp_crc32.h>
79 #endif
80
81 #ifdef IPSEC
82 #include <netinet/ip_ipsec.h>
83 #include <netipsec/ipsec.h>
84 #endif /* IPSEC*/
85
86 #include <machine/in_cksum.h>
87
88 #include <security/mac/mac_framework.h>
89
90 VNET_DEFINE(u_short, ip_id);
91
92 #ifdef MBUF_STRESS_TEST
93 static int mbuf_frag_size = 0;
94 SYSCTL_INT(_net_inet_ip, OID_AUTO, mbuf_frag_size, CTLFLAG_RW,
95 &mbuf_frag_size, 0, "Fragment outgoing mbufs to this size");
96 #endif
97
98 static void ip_mloopback
99 (struct ifnet *, struct mbuf *, struct sockaddr_in *, int);
100
101
102 extern int in_mcast_loop;
103 extern struct protosw inetsw[];
104
105 /*
106 * IP output. The packet in mbuf chain m contains a skeletal IP
107 * header (with len, off, ttl, proto, tos, src, dst).
108 * The mbuf chain containing the packet will be freed.
109 * The mbuf opt, if present, will not be freed.
110 * If route ro is present and has ro_rt initialized, route lookup would be
111 * skipped and ro->ro_rt would be used. If ro is present but ro->ro_rt is NULL,
112 * then result of route lookup is stored in ro->ro_rt.
113 *
114 * In the IP forwarding case, the packet will arrive with options already
115 * inserted, so must have a NULL opt pointer.
116 */
117 int
118 ip_output(struct mbuf *m, struct mbuf *opt, struct route *ro, int flags,
119 struct ip_moptions *imo, struct inpcb *inp)
120 {
121 struct ip *ip;
122 struct ifnet *ifp = NULL; /* keep compiler happy */
123 struct mbuf *m0;
124 int hlen = sizeof (struct ip);
125 int mtu;
126 int n; /* scratchpad */
127 int error = 0;
128 struct sockaddr_in *dst;
129 const struct sockaddr_in *gw;
130 struct in_ifaddr *ia;
131 int isbroadcast;
132 uint16_t ip_len, ip_off;
133 struct route iproute;
134 struct rtentry *rte; /* cache for ro->ro_rt */
135 struct in_addr odst;
136 struct m_tag *fwd_tag = NULL;
137 #ifdef IPSEC
138 int no_route_but_check_spd = 0;
139 #endif
140 M_ASSERTPKTHDR(m);
141
142 if (inp != NULL) {
143 INP_LOCK_ASSERT(inp);
144 M_SETFIB(m, inp->inp_inc.inc_fibnum);
145 if (inp->inp_flags & (INP_HW_FLOWID|INP_SW_FLOWID)) {
146 m->m_pkthdr.flowid = inp->inp_flowid;
147 m->m_flags |= M_FLOWID;
148 }
149 }
150
151 if (ro == NULL) {
152 ro = &iproute;
153 bzero(ro, sizeof (*ro));
154 }
155
156 #ifdef FLOWTABLE
157 if (ro->ro_rt == NULL) {
158 struct flentry *fle;
159
160 /*
161 * The flow table returns route entries valid for up to 30
162 * seconds; we rely on the remainder of ip_output() taking no
163 * longer than that long for the stability of ro_rt. The
164 * flow ID assignment must have happened before this point.
165 */
166 fle = flowtable_lookup_mbuf(V_ip_ft, m, AF_INET);
167 if (fle != NULL)
168 flow_to_route(fle, ro);
169 }
170 #endif
171
172 if (opt) {
173 int len = 0;
174 m = ip_insertoptions(m, opt, &len);
175 if (len != 0)
176 hlen = len; /* ip->ip_hl is updated above */
177 }
178 ip = mtod(m, struct ip *);
179 ip_len = ntohs(ip->ip_len);
180 ip_off = ntohs(ip->ip_off);
181
182 /*
183 * Fill in IP header. If we are not allowing fragmentation,
184 * then the ip_id field is meaningless, but we don't set it
185 * to zero. Doing so causes various problems when devices along
186 * the path (routers, load balancers, firewalls, etc.) illegally
187 * disable DF on our packet. Note that a 16-bit counter
188 * will wrap around in less than 10 seconds at 100 Mbit/s on a
189 * medium with MTU 1500. See Steven M. Bellovin, "A Technique
190 * for Counting NATted Hosts", Proc. IMW'02, available at
191 * <http://www.cs.columbia.edu/~smb/papers/fnat.pdf>.
192 */
193 if ((flags & (IP_FORWARDING|IP_RAWOUTPUT)) == 0) {
194 ip->ip_v = IPVERSION;
195 ip->ip_hl = hlen >> 2;
196 ip->ip_id = ip_newid();
197 IPSTAT_INC(ips_localout);
198 } else {
199 /* Header already set, fetch hlen from there */
200 hlen = ip->ip_hl << 2;
201 }
202
203 gw = dst = (struct sockaddr_in *)&ro->ro_dst;
204 again:
205 ia = NULL;
206 /*
207 * If there is a cached route,
208 * check that it is to the same destination
209 * and is still up. If not, free it and try again.
210 * The address family should also be checked in case of sharing the
211 * cache with IPv6.
212 */
213 rte = ro->ro_rt;
214 if (rte && ((rte->rt_flags & RTF_UP) == 0 ||
215 rte->rt_ifp == NULL ||
216 !RT_LINK_IS_UP(rte->rt_ifp) ||
217 dst->sin_family != AF_INET ||
218 dst->sin_addr.s_addr != ip->ip_dst.s_addr)) {
219 RO_RTFREE(ro);
220 ro->ro_lle = NULL;
221 rte = NULL;
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 ip->ip_dst.s_addr = INADDR_BROADCAST;
243 dst->sin_addr = ip->ip_dst;
244 ifp = ia->ia_ifp;
245 ip->ip_ttl = 1;
246 isbroadcast = 1;
247 } else if (flags & IP_ROUTETOIF) {
248 if ((ia = ifatoia(ifa_ifwithdstaddr(sintosa(dst)))) == NULL &&
249 (ia = ifatoia(ifa_ifwithnet(sintosa(dst), 0))) == NULL) {
250 IPSTAT_INC(ips_noroute);
251 error = ENETUNREACH;
252 goto bad;
253 }
254 ifp = ia->ia_ifp;
255 ip->ip_ttl = 1;
256 isbroadcast = in_broadcast(dst->sin_addr, ifp);
257 } else if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr)) &&
258 imo != NULL && imo->imo_multicast_ifp != NULL) {
259 /*
260 * Bypass the normal routing lookup for multicast
261 * packets if the interface is specified.
262 */
263 ifp = imo->imo_multicast_ifp;
264 IFP_TO_IA(ifp, ia);
265 isbroadcast = 0; /* fool gcc */
266 } else {
267 /*
268 * We want to do any cloning requested by the link layer,
269 * as this is probably required in all cases for correct
270 * operation (as it is for ARP).
271 */
272 if (rte == NULL) {
273 #ifdef RADIX_MPATH
274 rtalloc_mpath_fib(ro,
275 ntohl(ip->ip_src.s_addr ^ ip->ip_dst.s_addr),
276 inp ? inp->inp_inc.inc_fibnum : M_GETFIB(m));
277 #else
278 in_rtalloc_ign(ro, 0,
279 inp ? inp->inp_inc.inc_fibnum : M_GETFIB(m));
280 #endif
281 rte = ro->ro_rt;
282 }
283 if (rte == NULL ||
284 rte->rt_ifp == NULL ||
285 !RT_LINK_IS_UP(rte->rt_ifp)) {
286 #ifdef IPSEC
287 /*
288 * There is no route for this packet, but it is
289 * possible that a matching SPD entry exists.
290 */
291 no_route_but_check_spd = 1;
292 mtu = 0; /* Silence GCC warning. */
293 goto sendit;
294 #endif
295 IPSTAT_INC(ips_noroute);
296 error = EHOSTUNREACH;
297 goto bad;
298 }
299 ia = ifatoia(rte->rt_ifa);
300 ifa_ref(&ia->ia_ifa);
301 ifp = rte->rt_ifp;
302 rte->rt_rmx.rmx_pksent++;
303 if (rte->rt_flags & RTF_GATEWAY)
304 gw = (struct sockaddr_in *)rte->rt_gateway;
305 if (rte->rt_flags & RTF_HOST)
306 isbroadcast = (rte->rt_flags & RTF_BROADCAST);
307 else
308 isbroadcast = in_broadcast(gw->sin_addr, ifp);
309 }
310 /*
311 * Calculate MTU. If we have a route that is up, use that,
312 * otherwise use the interface's MTU.
313 */
314 if (rte != NULL && (rte->rt_flags & (RTF_UP|RTF_HOST))) {
315 /*
316 * This case can happen if the user changed the MTU
317 * of an interface after enabling IP on it. Because
318 * most netifs don't keep track of routes pointing to
319 * them, there is no way for one to update all its
320 * routes when the MTU is changed.
321 */
322 if (rte->rt_rmx.rmx_mtu > ifp->if_mtu)
323 rte->rt_rmx.rmx_mtu = ifp->if_mtu;
324 mtu = rte->rt_rmx.rmx_mtu;
325 } else {
326 mtu = ifp->if_mtu;
327 }
328 /* Catch a possible divide by zero later. */
329 KASSERT(mtu > 0, ("%s: mtu %d <= 0, rte=%p (rt_flags=0x%08x) ifp=%p",
330 __func__, mtu, rte, (rte != NULL) ? rte->rt_flags : 0, ifp));
331 if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) {
332 m->m_flags |= M_MCAST;
333 /*
334 * IP destination address is multicast. Make sure "gw"
335 * still points to the address in "ro". (It may have been
336 * changed to point to a gateway address, above.)
337 */
338 gw = dst;
339 /*
340 * See if the caller provided any multicast options
341 */
342 if (imo != NULL) {
343 ip->ip_ttl = imo->imo_multicast_ttl;
344 if (imo->imo_multicast_vif != -1)
345 ip->ip_src.s_addr =
346 ip_mcast_src ?
347 ip_mcast_src(imo->imo_multicast_vif) :
348 INADDR_ANY;
349 } else
350 ip->ip_ttl = IP_DEFAULT_MULTICAST_TTL;
351 /*
352 * Confirm that the outgoing interface supports multicast.
353 */
354 if ((imo == NULL) || (imo->imo_multicast_vif == -1)) {
355 if ((ifp->if_flags & IFF_MULTICAST) == 0) {
356 IPSTAT_INC(ips_noroute);
357 error = ENETUNREACH;
358 goto bad;
359 }
360 }
361 /*
362 * If source address not specified yet, use address
363 * of outgoing interface.
364 */
365 if (ip->ip_src.s_addr == INADDR_ANY) {
366 /* Interface may have no addresses. */
367 if (ia != NULL)
368 ip->ip_src = IA_SIN(ia)->sin_addr;
369 }
370
371 if ((imo == NULL && in_mcast_loop) ||
372 (imo && imo->imo_multicast_loop)) {
373 /*
374 * Loop back multicast datagram if not expressly
375 * forbidden to do so, even if we are not a member
376 * of the group; ip_input() will filter it later,
377 * thus deferring a hash lookup and mutex acquisition
378 * at the expense of a cheap copy using m_copym().
379 */
380 ip_mloopback(ifp, m, dst, hlen);
381 } else {
382 /*
383 * If we are acting as a multicast router, perform
384 * multicast forwarding as if the packet had just
385 * arrived on the interface to which we are about
386 * to send. The multicast forwarding function
387 * recursively calls this function, using the
388 * IP_FORWARDING flag to prevent infinite recursion.
389 *
390 * Multicasts that are looped back by ip_mloopback(),
391 * above, will be forwarded by the ip_input() routine,
392 * if necessary.
393 */
394 if (V_ip_mrouter && (flags & IP_FORWARDING) == 0) {
395 /*
396 * If rsvp daemon is not running, do not
397 * set ip_moptions. This ensures that the packet
398 * is multicast and not just sent down one link
399 * as prescribed by rsvpd.
400 */
401 if (!V_rsvp_on)
402 imo = NULL;
403 if (ip_mforward &&
404 ip_mforward(ip, ifp, m, imo) != 0) {
405 m_freem(m);
406 goto done;
407 }
408 }
409 }
410
411 /*
412 * Multicasts with a time-to-live of zero may be looped-
413 * back, above, but must not be transmitted on a network.
414 * Also, multicasts addressed to the loopback interface
415 * are not sent -- the above call to ip_mloopback() will
416 * loop back a copy. ip_input() will drop the copy if
417 * this host does not belong to the destination group on
418 * the loopback interface.
419 */
420 if (ip->ip_ttl == 0 || ifp->if_flags & IFF_LOOPBACK) {
421 m_freem(m);
422 goto done;
423 }
424
425 goto sendit;
426 }
427
428 /*
429 * If the source address is not specified yet, use the address
430 * of the outoing interface.
431 */
432 if (ip->ip_src.s_addr == INADDR_ANY) {
433 /* Interface may have no addresses. */
434 if (ia != NULL) {
435 ip->ip_src = IA_SIN(ia)->sin_addr;
436 }
437 }
438
439 /*
440 * Verify that we have any chance at all of being able to queue the
441 * packet or packet fragments, unless ALTQ is enabled on the given
442 * interface in which case packetdrop should be done by queueing.
443 */
444 n = ip_len / mtu + 1; /* how many fragments ? */
445 if (
446 #ifdef ALTQ
447 (!ALTQ_IS_ENABLED(&ifp->if_snd)) &&
448 #endif /* ALTQ */
449 (ifp->if_snd.ifq_len + n) >= ifp->if_snd.ifq_maxlen ) {
450 error = ENOBUFS;
451 IPSTAT_INC(ips_odropped);
452 ifp->if_snd.ifq_drops += n;
453 goto bad;
454 }
455
456 /*
457 * Look for broadcast address and
458 * verify user is allowed to send
459 * such a packet.
460 */
461 if (isbroadcast) {
462 if ((ifp->if_flags & IFF_BROADCAST) == 0) {
463 error = EADDRNOTAVAIL;
464 goto bad;
465 }
466 if ((flags & IP_ALLOWBROADCAST) == 0) {
467 error = EACCES;
468 goto bad;
469 }
470 /* don't allow broadcast messages to be fragmented */
471 if (ip_len > mtu) {
472 error = EMSGSIZE;
473 goto bad;
474 }
475 m->m_flags |= M_BCAST;
476 } else {
477 m->m_flags &= ~M_BCAST;
478 }
479
480 sendit:
481 #ifdef IPSEC
482 switch(ip_ipsec_output(&m, inp, &flags, &error)) {
483 case 1:
484 goto bad;
485 case -1:
486 goto done;
487 case 0:
488 default:
489 break; /* Continue with packet processing. */
490 }
491 /*
492 * Check if there was a route for this packet; return error if not.
493 */
494 if (no_route_but_check_spd) {
495 IPSTAT_INC(ips_noroute);
496 error = EHOSTUNREACH;
497 goto bad;
498 }
499 /* Update variables that are affected by ipsec4_output(). */
500 ip = mtod(m, struct ip *);
501 hlen = ip->ip_hl << 2;
502 #endif /* IPSEC */
503
504 /* Jump over all PFIL processing if hooks are not active. */
505 if (!PFIL_HOOKED(&V_inet_pfil_hook))
506 goto passout;
507
508 /* Run through list of hooks for output packets. */
509 odst.s_addr = ip->ip_dst.s_addr;
510 error = pfil_run_hooks(&V_inet_pfil_hook, &m, ifp, PFIL_OUT, inp);
511 if (error != 0 || m == NULL)
512 goto done;
513
514 ip = mtod(m, struct ip *);
515
516 /* See if destination IP address was changed by packet filter. */
517 if (odst.s_addr != ip->ip_dst.s_addr) {
518 m->m_flags |= M_SKIP_FIREWALL;
519 /* If destination is now ourself drop to ip_input(). */
520 if (in_localip(ip->ip_dst)) {
521 m->m_flags |= M_FASTFWD_OURS;
522 if (m->m_pkthdr.rcvif == NULL)
523 m->m_pkthdr.rcvif = V_loif;
524 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
525 m->m_pkthdr.csum_flags |=
526 CSUM_DATA_VALID | CSUM_PSEUDO_HDR;
527 m->m_pkthdr.csum_data = 0xffff;
528 }
529 m->m_pkthdr.csum_flags |=
530 CSUM_IP_CHECKED | CSUM_IP_VALID;
531 #ifdef SCTP
532 if (m->m_pkthdr.csum_flags & CSUM_SCTP)
533 m->m_pkthdr.csum_flags |= CSUM_SCTP_VALID;
534 #endif
535 error = netisr_queue(NETISR_IP, m);
536 goto done;
537 } else {
538 if (ia != NULL)
539 ifa_free(&ia->ia_ifa);
540 goto again; /* Redo the routing table lookup. */
541 }
542 }
543
544 /* See if local, if yes, send it to netisr with IP_FASTFWD_OURS. */
545 if (m->m_flags & M_FASTFWD_OURS) {
546 if (m->m_pkthdr.rcvif == NULL)
547 m->m_pkthdr.rcvif = V_loif;
548 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
549 m->m_pkthdr.csum_flags |=
550 CSUM_DATA_VALID | CSUM_PSEUDO_HDR;
551 m->m_pkthdr.csum_data = 0xffff;
552 }
553 #ifdef SCTP
554 if (m->m_pkthdr.csum_flags & CSUM_SCTP)
555 m->m_pkthdr.csum_flags |= CSUM_SCTP_VALID;
556 #endif
557 m->m_pkthdr.csum_flags |=
558 CSUM_IP_CHECKED | CSUM_IP_VALID;
559
560 error = netisr_queue(NETISR_IP, m);
561 goto done;
562 }
563 /* Or forward to some other address? */
564 if ((m->m_flags & M_IP_NEXTHOP) &&
565 (fwd_tag = m_tag_find(m, PACKET_TAG_IPFORWARD, NULL)) != NULL) {
566 bcopy((fwd_tag+1), dst, sizeof(struct sockaddr_in));
567 m->m_flags |= M_SKIP_FIREWALL;
568 m->m_flags &= ~M_IP_NEXTHOP;
569 m_tag_delete(m, fwd_tag);
570 if (ia != NULL)
571 ifa_free(&ia->ia_ifa);
572 goto again;
573 }
574
575 passout:
576 /* 127/8 must not appear on wire - RFC1122. */
577 if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET ||
578 (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) {
579 if ((ifp->if_flags & IFF_LOOPBACK) == 0) {
580 IPSTAT_INC(ips_badaddr);
581 error = EADDRNOTAVAIL;
582 goto bad;
583 }
584 }
585
586 m->m_pkthdr.csum_flags |= CSUM_IP;
587 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA & ~ifp->if_hwassist) {
588 in_delayed_cksum(m);
589 m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
590 }
591 #ifdef SCTP
592 if (m->m_pkthdr.csum_flags & CSUM_SCTP & ~ifp->if_hwassist) {
593 sctp_delayed_cksum(m, (uint32_t)(ip->ip_hl << 2));
594 m->m_pkthdr.csum_flags &= ~CSUM_SCTP;
595 }
596 #endif
597
598 /*
599 * If small enough for interface, or the interface will take
600 * care of the fragmentation for us, we can just send directly.
601 */
602 if (ip_len <= mtu ||
603 (m->m_pkthdr.csum_flags & ifp->if_hwassist & CSUM_TSO) != 0 ||
604 ((ip_off & IP_DF) == 0 && (ifp->if_hwassist & CSUM_FRAGMENT))) {
605 ip->ip_sum = 0;
606 if (m->m_pkthdr.csum_flags & CSUM_IP & ~ifp->if_hwassist) {
607 ip->ip_sum = in_cksum(m, hlen);
608 m->m_pkthdr.csum_flags &= ~CSUM_IP;
609 }
610
611 /*
612 * Record statistics for this interface address.
613 * With CSUM_TSO the byte/packet count will be slightly
614 * incorrect because we count the IP+TCP headers only
615 * once instead of for every generated packet.
616 */
617 if (!(flags & IP_FORWARDING) && ia) {
618 if (m->m_pkthdr.csum_flags & CSUM_TSO)
619 ia->ia_ifa.if_opackets +=
620 m->m_pkthdr.len / m->m_pkthdr.tso_segsz;
621 else
622 ia->ia_ifa.if_opackets++;
623 ia->ia_ifa.if_obytes += m->m_pkthdr.len;
624 }
625 #ifdef MBUF_STRESS_TEST
626 if (mbuf_frag_size && m->m_pkthdr.len > mbuf_frag_size)
627 m = m_fragment(m, M_NOWAIT, mbuf_frag_size);
628 #endif
629 /*
630 * Reset layer specific mbuf flags
631 * to avoid confusing lower layers.
632 */
633 m_clrprotoflags(m);
634 IP_PROBE(send, NULL, NULL, ip, ifp, ip, NULL);
635 error = (*ifp->if_output)(ifp, m,
636 (const struct sockaddr *)gw, ro);
637 goto done;
638 }
639
640 /* Balk when DF bit is set or the interface didn't support TSO. */
641 if ((ip_off & IP_DF) || (m->m_pkthdr.csum_flags & CSUM_TSO)) {
642 error = EMSGSIZE;
643 IPSTAT_INC(ips_cantfrag);
644 goto bad;
645 }
646
647 /*
648 * Too large for interface; fragment if possible. If successful,
649 * on return, m will point to a list of packets to be sent.
650 */
651 error = ip_fragment(ip, &m, mtu, ifp->if_hwassist);
652 if (error)
653 goto bad;
654 for (; m; m = m0) {
655 m0 = m->m_nextpkt;
656 m->m_nextpkt = 0;
657 if (error == 0) {
658 /* Record statistics for this interface address. */
659 if (ia != NULL) {
660 ia->ia_ifa.if_opackets++;
661 ia->ia_ifa.if_obytes += m->m_pkthdr.len;
662 }
663 /*
664 * Reset layer specific mbuf flags
665 * to avoid confusing upper layers.
666 */
667 m_clrprotoflags(m);
668
669 IP_PROBE(send, NULL, NULL, ip, ifp, ip, NULL);
670 error = (*ifp->if_output)(ifp, m,
671 (const struct sockaddr *)gw, ro);
672 } else
673 m_freem(m);
674 }
675
676 if (error == 0)
677 IPSTAT_INC(ips_fragmented);
678
679 done:
680 if (ro == &iproute)
681 RO_RTFREE(ro);
682 if (ia != NULL)
683 ifa_free(&ia->ia_ifa);
684 return (error);
685 bad:
686 m_freem(m);
687 goto done;
688 }
689
690 /*
691 * Create a chain of fragments which fit the given mtu. m_frag points to the
692 * mbuf to be fragmented; on return it points to the chain with the fragments.
693 * Return 0 if no error. If error, m_frag may contain a partially built
694 * chain of fragments that should be freed by the caller.
695 *
696 * if_hwassist_flags is the hw offload capabilities (see if_data.ifi_hwassist)
697 */
698 int
699 ip_fragment(struct ip *ip, struct mbuf **m_frag, int mtu,
700 u_long if_hwassist_flags)
701 {
702 int error = 0;
703 int hlen = ip->ip_hl << 2;
704 int len = (mtu - hlen) & ~7; /* size of payload in each fragment */
705 int off;
706 struct mbuf *m0 = *m_frag; /* the original packet */
707 int firstlen;
708 struct mbuf **mnext;
709 int nfrags;
710 uint16_t ip_len, ip_off;
711
712 ip_len = ntohs(ip->ip_len);
713 ip_off = ntohs(ip->ip_off);
714
715 if (ip_off & IP_DF) { /* Fragmentation not allowed */
716 IPSTAT_INC(ips_cantfrag);
717 return EMSGSIZE;
718 }
719
720 /*
721 * Must be able to put at least 8 bytes per fragment.
722 */
723 if (len < 8)
724 return EMSGSIZE;
725
726 /*
727 * If the interface will not calculate checksums on
728 * fragmented packets, then do it here.
729 */
730 if (m0->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
731 in_delayed_cksum(m0);
732 m0->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
733 }
734 #ifdef SCTP
735 if (m0->m_pkthdr.csum_flags & CSUM_SCTP) {
736 sctp_delayed_cksum(m0, hlen);
737 m0->m_pkthdr.csum_flags &= ~CSUM_SCTP;
738 }
739 #endif
740 if (len > PAGE_SIZE) {
741 /*
742 * Fragment large datagrams such that each segment
743 * contains a multiple of PAGE_SIZE amount of data,
744 * plus headers. This enables a receiver to perform
745 * page-flipping zero-copy optimizations.
746 *
747 * XXX When does this help given that sender and receiver
748 * could have different page sizes, and also mtu could
749 * be less than the receiver's page size ?
750 */
751 int newlen;
752 struct mbuf *m;
753
754 for (m = m0, off = 0; m && (off+m->m_len) <= mtu; m = m->m_next)
755 off += m->m_len;
756
757 /*
758 * firstlen (off - hlen) must be aligned on an
759 * 8-byte boundary
760 */
761 if (off < hlen)
762 goto smart_frag_failure;
763 off = ((off - hlen) & ~7) + hlen;
764 newlen = (~PAGE_MASK) & mtu;
765 if ((newlen + sizeof (struct ip)) > mtu) {
766 /* we failed, go back the default */
767 smart_frag_failure:
768 newlen = len;
769 off = hlen + len;
770 }
771 len = newlen;
772
773 } else {
774 off = hlen + len;
775 }
776
777 firstlen = off - hlen;
778 mnext = &m0->m_nextpkt; /* pointer to next packet */
779
780 /*
781 * Loop through length of segment after first fragment,
782 * make new header and copy data of each part and link onto chain.
783 * Here, m0 is the original packet, m is the fragment being created.
784 * The fragments are linked off the m_nextpkt of the original
785 * packet, which after processing serves as the first fragment.
786 */
787 for (nfrags = 1; off < ip_len; off += len, nfrags++) {
788 struct ip *mhip; /* ip header on the fragment */
789 struct mbuf *m;
790 int mhlen = sizeof (struct ip);
791
792 m = m_gethdr(M_NOWAIT, MT_DATA);
793 if (m == NULL) {
794 error = ENOBUFS;
795 IPSTAT_INC(ips_odropped);
796 goto done;
797 }
798 m->m_flags |= (m0->m_flags & M_MCAST);
799 /*
800 * In the first mbuf, leave room for the link header, then
801 * copy the original IP header including options. The payload
802 * goes into an additional mbuf chain returned by m_copym().
803 */
804 m->m_data += max_linkhdr;
805 mhip = mtod(m, struct ip *);
806 *mhip = *ip;
807 if (hlen > sizeof (struct ip)) {
808 mhlen = ip_optcopy(ip, mhip) + sizeof (struct ip);
809 mhip->ip_v = IPVERSION;
810 mhip->ip_hl = mhlen >> 2;
811 }
812 m->m_len = mhlen;
813 /* XXX do we need to add ip_off below ? */
814 mhip->ip_off = ((off - hlen) >> 3) + ip_off;
815 if (off + len >= ip_len)
816 len = ip_len - off;
817 else
818 mhip->ip_off |= IP_MF;
819 mhip->ip_len = htons((u_short)(len + mhlen));
820 m->m_next = m_copym(m0, off, len, M_NOWAIT);
821 if (m->m_next == NULL) { /* copy failed */
822 m_free(m);
823 error = ENOBUFS; /* ??? */
824 IPSTAT_INC(ips_odropped);
825 goto done;
826 }
827 m->m_pkthdr.len = mhlen + len;
828 m->m_pkthdr.rcvif = NULL;
829 #ifdef MAC
830 mac_netinet_fragment(m0, m);
831 #endif
832 m->m_pkthdr.csum_flags = m0->m_pkthdr.csum_flags;
833 mhip->ip_off = htons(mhip->ip_off);
834 mhip->ip_sum = 0;
835 if (m->m_pkthdr.csum_flags & CSUM_IP & ~if_hwassist_flags) {
836 mhip->ip_sum = in_cksum(m, mhlen);
837 m->m_pkthdr.csum_flags &= ~CSUM_IP;
838 }
839 *mnext = m;
840 mnext = &m->m_nextpkt;
841 }
842 IPSTAT_ADD(ips_ofragments, nfrags);
843
844 /*
845 * Update first fragment by trimming what's been copied out
846 * and updating header.
847 */
848 m_adj(m0, hlen + firstlen - ip_len);
849 m0->m_pkthdr.len = hlen + firstlen;
850 ip->ip_len = htons((u_short)m0->m_pkthdr.len);
851 ip->ip_off = htons(ip_off | IP_MF);
852 ip->ip_sum = 0;
853 if (m0->m_pkthdr.csum_flags & CSUM_IP & ~if_hwassist_flags) {
854 ip->ip_sum = in_cksum(m0, hlen);
855 m0->m_pkthdr.csum_flags &= ~CSUM_IP;
856 }
857
858 done:
859 *m_frag = m0;
860 return error;
861 }
862
863 void
864 in_delayed_cksum(struct mbuf *m)
865 {
866 struct ip *ip;
867 uint16_t csum, offset, ip_len;
868
869 ip = mtod(m, struct ip *);
870 offset = ip->ip_hl << 2 ;
871 ip_len = ntohs(ip->ip_len);
872 csum = in_cksum_skip(m, ip_len, offset);
873 if (m->m_pkthdr.csum_flags & CSUM_UDP && csum == 0)
874 csum = 0xffff;
875 offset += m->m_pkthdr.csum_data; /* checksum offset */
876
877 if (offset + sizeof(u_short) > m->m_len) {
878 printf("delayed m_pullup, m->len: %d off: %d p: %d\n",
879 m->m_len, offset, ip->ip_p);
880 /*
881 * XXX
882 * this shouldn't happen, but if it does, the
883 * correct behavior may be to insert the checksum
884 * in the appropriate next mbuf in the chain.
885 */
886 return;
887 }
888 *(u_short *)(m->m_data + offset) = csum;
889 }
890
891 /*
892 * IP socket option processing.
893 */
894 int
895 ip_ctloutput(struct socket *so, struct sockopt *sopt)
896 {
897 struct inpcb *inp = sotoinpcb(so);
898 int error, optval;
899
900 error = optval = 0;
901 if (sopt->sopt_level != IPPROTO_IP) {
902 error = EINVAL;
903
904 if (sopt->sopt_level == SOL_SOCKET &&
905 sopt->sopt_dir == SOPT_SET) {
906 switch (sopt->sopt_name) {
907 case SO_REUSEADDR:
908 INP_WLOCK(inp);
909 if ((so->so_options & SO_REUSEADDR) != 0)
910 inp->inp_flags2 |= INP_REUSEADDR;
911 else
912 inp->inp_flags2 &= ~INP_REUSEADDR;
913 INP_WUNLOCK(inp);
914 error = 0;
915 break;
916 case SO_REUSEPORT:
917 INP_WLOCK(inp);
918 if ((so->so_options & SO_REUSEPORT) != 0)
919 inp->inp_flags2 |= INP_REUSEPORT;
920 else
921 inp->inp_flags2 &= ~INP_REUSEPORT;
922 INP_WUNLOCK(inp);
923 error = 0;
924 break;
925 case SO_SETFIB:
926 INP_WLOCK(inp);
927 inp->inp_inc.inc_fibnum = so->so_fibnum;
928 INP_WUNLOCK(inp);
929 error = 0;
930 break;
931 default:
932 break;
933 }
934 }
935 return (error);
936 }
937
938 switch (sopt->sopt_dir) {
939 case SOPT_SET:
940 switch (sopt->sopt_name) {
941 case IP_OPTIONS:
942 #ifdef notyet
943 case IP_RETOPTS:
944 #endif
945 {
946 struct mbuf *m;
947 if (sopt->sopt_valsize > MLEN) {
948 error = EMSGSIZE;
949 break;
950 }
951 m = m_get(sopt->sopt_td ? M_WAITOK : M_NOWAIT, MT_DATA);
952 if (m == NULL) {
953 error = ENOBUFS;
954 break;
955 }
956 m->m_len = sopt->sopt_valsize;
957 error = sooptcopyin(sopt, mtod(m, char *), m->m_len,
958 m->m_len);
959 if (error) {
960 m_free(m);
961 break;
962 }
963 INP_WLOCK(inp);
964 error = ip_pcbopts(inp, sopt->sopt_name, m);
965 INP_WUNLOCK(inp);
966 return (error);
967 }
968
969 case IP_BINDANY:
970 if (sopt->sopt_td != NULL) {
971 error = priv_check(sopt->sopt_td,
972 PRIV_NETINET_BINDANY);
973 if (error)
974 break;
975 }
976 /* FALLTHROUGH */
977 case IP_TOS:
978 case IP_TTL:
979 case IP_MINTTL:
980 case IP_RECVOPTS:
981 case IP_RECVRETOPTS:
982 case IP_RECVDSTADDR:
983 case IP_RECVTTL:
984 case IP_RECVIF:
985 case IP_FAITH:
986 case IP_ONESBCAST:
987 case IP_DONTFRAG:
988 case IP_RECVTOS:
989 error = sooptcopyin(sopt, &optval, sizeof optval,
990 sizeof optval);
991 if (error)
992 break;
993
994 switch (sopt->sopt_name) {
995 case IP_TOS:
996 inp->inp_ip_tos = optval;
997 break;
998
999 case IP_TTL:
1000 inp->inp_ip_ttl = optval;
1001 break;
1002
1003 case IP_MINTTL:
1004 if (optval >= 0 && optval <= MAXTTL)
1005 inp->inp_ip_minttl = optval;
1006 else
1007 error = EINVAL;
1008 break;
1009
1010 #define OPTSET(bit) do { \
1011 INP_WLOCK(inp); \
1012 if (optval) \
1013 inp->inp_flags |= bit; \
1014 else \
1015 inp->inp_flags &= ~bit; \
1016 INP_WUNLOCK(inp); \
1017 } while (0)
1018
1019 case IP_RECVOPTS:
1020 OPTSET(INP_RECVOPTS);
1021 break;
1022
1023 case IP_RECVRETOPTS:
1024 OPTSET(INP_RECVRETOPTS);
1025 break;
1026
1027 case IP_RECVDSTADDR:
1028 OPTSET(INP_RECVDSTADDR);
1029 break;
1030
1031 case IP_RECVTTL:
1032 OPTSET(INP_RECVTTL);
1033 break;
1034
1035 case IP_RECVIF:
1036 OPTSET(INP_RECVIF);
1037 break;
1038
1039 case IP_FAITH:
1040 OPTSET(INP_FAITH);
1041 break;
1042
1043 case IP_ONESBCAST:
1044 OPTSET(INP_ONESBCAST);
1045 break;
1046 case IP_DONTFRAG:
1047 OPTSET(INP_DONTFRAG);
1048 break;
1049 case IP_BINDANY:
1050 OPTSET(INP_BINDANY);
1051 break;
1052 case IP_RECVTOS:
1053 OPTSET(INP_RECVTOS);
1054 break;
1055 }
1056 break;
1057 #undef OPTSET
1058
1059 /*
1060 * Multicast socket options are processed by the in_mcast
1061 * module.
1062 */
1063 case IP_MULTICAST_IF:
1064 case IP_MULTICAST_VIF:
1065 case IP_MULTICAST_TTL:
1066 case IP_MULTICAST_LOOP:
1067 case IP_ADD_MEMBERSHIP:
1068 case IP_DROP_MEMBERSHIP:
1069 case IP_ADD_SOURCE_MEMBERSHIP:
1070 case IP_DROP_SOURCE_MEMBERSHIP:
1071 case IP_BLOCK_SOURCE:
1072 case IP_UNBLOCK_SOURCE:
1073 case IP_MSFILTER:
1074 case MCAST_JOIN_GROUP:
1075 case MCAST_LEAVE_GROUP:
1076 case MCAST_JOIN_SOURCE_GROUP:
1077 case MCAST_LEAVE_SOURCE_GROUP:
1078 case MCAST_BLOCK_SOURCE:
1079 case MCAST_UNBLOCK_SOURCE:
1080 error = inp_setmoptions(inp, sopt);
1081 break;
1082
1083 case IP_PORTRANGE:
1084 error = sooptcopyin(sopt, &optval, sizeof optval,
1085 sizeof optval);
1086 if (error)
1087 break;
1088
1089 INP_WLOCK(inp);
1090 switch (optval) {
1091 case IP_PORTRANGE_DEFAULT:
1092 inp->inp_flags &= ~(INP_LOWPORT);
1093 inp->inp_flags &= ~(INP_HIGHPORT);
1094 break;
1095
1096 case IP_PORTRANGE_HIGH:
1097 inp->inp_flags &= ~(INP_LOWPORT);
1098 inp->inp_flags |= INP_HIGHPORT;
1099 break;
1100
1101 case IP_PORTRANGE_LOW:
1102 inp->inp_flags &= ~(INP_HIGHPORT);
1103 inp->inp_flags |= INP_LOWPORT;
1104 break;
1105
1106 default:
1107 error = EINVAL;
1108 break;
1109 }
1110 INP_WUNLOCK(inp);
1111 break;
1112
1113 #ifdef IPSEC
1114 case IP_IPSEC_POLICY:
1115 {
1116 caddr_t req;
1117 struct mbuf *m;
1118
1119 if ((error = soopt_getm(sopt, &m)) != 0) /* XXX */
1120 break;
1121 if ((error = soopt_mcopyin(sopt, m)) != 0) /* XXX */
1122 break;
1123 req = mtod(m, caddr_t);
1124 error = ipsec_set_policy(inp, sopt->sopt_name, req,
1125 m->m_len, (sopt->sopt_td != NULL) ?
1126 sopt->sopt_td->td_ucred : NULL);
1127 m_freem(m);
1128 break;
1129 }
1130 #endif /* IPSEC */
1131
1132 default:
1133 error = ENOPROTOOPT;
1134 break;
1135 }
1136 break;
1137
1138 case SOPT_GET:
1139 switch (sopt->sopt_name) {
1140 case IP_OPTIONS:
1141 case IP_RETOPTS:
1142 if (inp->inp_options)
1143 error = sooptcopyout(sopt,
1144 mtod(inp->inp_options,
1145 char *),
1146 inp->inp_options->m_len);
1147 else
1148 sopt->sopt_valsize = 0;
1149 break;
1150
1151 case IP_TOS:
1152 case IP_TTL:
1153 case IP_MINTTL:
1154 case IP_RECVOPTS:
1155 case IP_RECVRETOPTS:
1156 case IP_RECVDSTADDR:
1157 case IP_RECVTTL:
1158 case IP_RECVIF:
1159 case IP_PORTRANGE:
1160 case IP_FAITH:
1161 case IP_ONESBCAST:
1162 case IP_DONTFRAG:
1163 case IP_BINDANY:
1164 case IP_RECVTOS:
1165 switch (sopt->sopt_name) {
1166
1167 case IP_TOS:
1168 optval = inp->inp_ip_tos;
1169 break;
1170
1171 case IP_TTL:
1172 optval = inp->inp_ip_ttl;
1173 break;
1174
1175 case IP_MINTTL:
1176 optval = inp->inp_ip_minttl;
1177 break;
1178
1179 #define OPTBIT(bit) (inp->inp_flags & bit ? 1 : 0)
1180
1181 case IP_RECVOPTS:
1182 optval = OPTBIT(INP_RECVOPTS);
1183 break;
1184
1185 case IP_RECVRETOPTS:
1186 optval = OPTBIT(INP_RECVRETOPTS);
1187 break;
1188
1189 case IP_RECVDSTADDR:
1190 optval = OPTBIT(INP_RECVDSTADDR);
1191 break;
1192
1193 case IP_RECVTTL:
1194 optval = OPTBIT(INP_RECVTTL);
1195 break;
1196
1197 case IP_RECVIF:
1198 optval = OPTBIT(INP_RECVIF);
1199 break;
1200
1201 case IP_PORTRANGE:
1202 if (inp->inp_flags & INP_HIGHPORT)
1203 optval = IP_PORTRANGE_HIGH;
1204 else if (inp->inp_flags & INP_LOWPORT)
1205 optval = IP_PORTRANGE_LOW;
1206 else
1207 optval = 0;
1208 break;
1209
1210 case IP_FAITH:
1211 optval = OPTBIT(INP_FAITH);
1212 break;
1213
1214 case IP_ONESBCAST:
1215 optval = OPTBIT(INP_ONESBCAST);
1216 break;
1217 case IP_DONTFRAG:
1218 optval = OPTBIT(INP_DONTFRAG);
1219 break;
1220 case IP_BINDANY:
1221 optval = OPTBIT(INP_BINDANY);
1222 break;
1223 case IP_RECVTOS:
1224 optval = OPTBIT(INP_RECVTOS);
1225 break;
1226 }
1227 error = sooptcopyout(sopt, &optval, sizeof optval);
1228 break;
1229
1230 /*
1231 * Multicast socket options are processed by the in_mcast
1232 * module.
1233 */
1234 case IP_MULTICAST_IF:
1235 case IP_MULTICAST_VIF:
1236 case IP_MULTICAST_TTL:
1237 case IP_MULTICAST_LOOP:
1238 case IP_MSFILTER:
1239 error = inp_getmoptions(inp, sopt);
1240 break;
1241
1242 #ifdef IPSEC
1243 case IP_IPSEC_POLICY:
1244 {
1245 struct mbuf *m = NULL;
1246 caddr_t req = NULL;
1247 size_t len = 0;
1248
1249 if (m != 0) {
1250 req = mtod(m, caddr_t);
1251 len = m->m_len;
1252 }
1253 error = ipsec_get_policy(sotoinpcb(so), req, len, &m);
1254 if (error == 0)
1255 error = soopt_mcopyout(sopt, m); /* XXX */
1256 if (error == 0)
1257 m_freem(m);
1258 break;
1259 }
1260 #endif /* IPSEC */
1261
1262 default:
1263 error = ENOPROTOOPT;
1264 break;
1265 }
1266 break;
1267 }
1268 return (error);
1269 }
1270
1271 /*
1272 * Routine called from ip_output() to loop back a copy of an IP multicast
1273 * packet to the input queue of a specified interface. Note that this
1274 * calls the output routine of the loopback "driver", but with an interface
1275 * pointer that might NOT be a loopback interface -- evil, but easier than
1276 * replicating that code here.
1277 */
1278 static void
1279 ip_mloopback(struct ifnet *ifp, struct mbuf *m, struct sockaddr_in *dst,
1280 int hlen)
1281 {
1282 register struct ip *ip;
1283 struct mbuf *copym;
1284
1285 /*
1286 * Make a deep copy of the packet because we're going to
1287 * modify the pack in order to generate checksums.
1288 */
1289 copym = m_dup(m, M_NOWAIT);
1290 if (copym != NULL && (copym->m_flags & M_EXT || copym->m_len < hlen))
1291 copym = m_pullup(copym, hlen);
1292 if (copym != NULL) {
1293 /* If needed, compute the checksum and mark it as valid. */
1294 if (copym->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
1295 in_delayed_cksum(copym);
1296 copym->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
1297 copym->m_pkthdr.csum_flags |=
1298 CSUM_DATA_VALID | CSUM_PSEUDO_HDR;
1299 copym->m_pkthdr.csum_data = 0xffff;
1300 }
1301 /*
1302 * We don't bother to fragment if the IP length is greater
1303 * than the interface's MTU. Can this possibly matter?
1304 */
1305 ip = mtod(copym, struct ip *);
1306 ip->ip_sum = 0;
1307 ip->ip_sum = in_cksum(copym, hlen);
1308 #if 1 /* XXX */
1309 if (dst->sin_family != AF_INET) {
1310 printf("ip_mloopback: bad address family %d\n",
1311 dst->sin_family);
1312 dst->sin_family = AF_INET;
1313 }
1314 #endif
1315 if_simloop(ifp, copym, dst->sin_family, 0);
1316 }
1317 }
Cache object: 8b5c02cb8806cc163d66647efb909e77
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