xref: /freebsd/sys/netinet/ip_output.c (revision 1f4bcc459a76b7aa664f3fd557684cd0ba6da352)
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("$FreeBSD$");
34 
35 #include "opt_inet.h"
36 #include "opt_ipfw.h"
37 #include "opt_ipsec.h"
38 #include "opt_mbuf_stress_test.h"
39 #include "opt_mpath.h"
40 #include "opt_route.h"
41 #include "opt_sctp.h"
42 #include "opt_rss.h"
43 
44 #include <sys/param.h>
45 #include <sys/systm.h>
46 #include <sys/kernel.h>
47 #include <sys/lock.h>
48 #include <sys/malloc.h>
49 #include <sys/mbuf.h>
50 #include <sys/priv.h>
51 #include <sys/proc.h>
52 #include <sys/protosw.h>
53 #include <sys/rmlock.h>
54 #include <sys/sdt.h>
55 #include <sys/socket.h>
56 #include <sys/socketvar.h>
57 #include <sys/sysctl.h>
58 #include <sys/ucred.h>
59 
60 #include <net/if.h>
61 #include <net/if_var.h>
62 #include <net/if_llatbl.h>
63 #include <net/netisr.h>
64 #include <net/pfil.h>
65 #include <net/route.h>
66 #include <net/flowtable.h>
67 #ifdef RADIX_MPATH
68 #include <net/radix_mpath.h>
69 #endif
70 #include <net/rss_config.h>
71 #include <net/vnet.h>
72 
73 #include <netinet/in.h>
74 #include <netinet/in_kdtrace.h>
75 #include <netinet/in_systm.h>
76 #include <netinet/ip.h>
77 #include <netinet/in_pcb.h>
78 #include <netinet/in_rss.h>
79 #include <netinet/in_var.h>
80 #include <netinet/ip_var.h>
81 #include <netinet/ip_options.h>
82 #ifdef SCTP
83 #include <netinet/sctp.h>
84 #include <netinet/sctp_crc32.h>
85 #endif
86 
87 #ifdef IPSEC
88 #include <netinet/ip_ipsec.h>
89 #include <netipsec/ipsec.h>
90 #endif /* IPSEC*/
91 
92 #include <machine/in_cksum.h>
93 
94 #include <security/mac/mac_framework.h>
95 
96 #ifdef MBUF_STRESS_TEST
97 static int mbuf_frag_size = 0;
98 SYSCTL_INT(_net_inet_ip, OID_AUTO, mbuf_frag_size, CTLFLAG_RW,
99 	&mbuf_frag_size, 0, "Fragment outgoing mbufs to this size");
100 #endif
101 
102 static void	ip_mloopback(struct ifnet *, const struct mbuf *, int);
103 
104 
105 extern int in_mcast_loop;
106 extern	struct protosw inetsw[];
107 
108 static inline int
109 ip_output_pfil(struct mbuf **mp, struct ifnet *ifp, struct inpcb *inp,
110     struct sockaddr_in *dst, int *fibnum, int *error)
111 {
112 	struct m_tag *fwd_tag = NULL;
113 	struct mbuf *m;
114 	struct in_addr odst;
115 	struct ip *ip;
116 
117 	m = *mp;
118 	ip = mtod(m, struct ip *);
119 
120 	/* Run through list of hooks for output packets. */
121 	odst.s_addr = ip->ip_dst.s_addr;
122 	*error = pfil_run_hooks(&V_inet_pfil_hook, mp, ifp, PFIL_OUT, inp);
123 	m = *mp;
124 	if ((*error) != 0 || m == NULL)
125 		return 1; /* Finished */
126 
127 	ip = mtod(m, struct ip *);
128 
129 	/* See if destination IP address was changed by packet filter. */
130 	if (odst.s_addr != ip->ip_dst.s_addr) {
131 		m->m_flags |= M_SKIP_FIREWALL;
132 		/* If destination is now ourself drop to ip_input(). */
133 		if (in_localip(ip->ip_dst)) {
134 			m->m_flags |= M_FASTFWD_OURS;
135 			if (m->m_pkthdr.rcvif == NULL)
136 				m->m_pkthdr.rcvif = V_loif;
137 			if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
138 				m->m_pkthdr.csum_flags |=
139 					CSUM_DATA_VALID | CSUM_PSEUDO_HDR;
140 				m->m_pkthdr.csum_data = 0xffff;
141 			}
142 			m->m_pkthdr.csum_flags |=
143 				CSUM_IP_CHECKED | CSUM_IP_VALID;
144 #ifdef SCTP
145 			if (m->m_pkthdr.csum_flags & CSUM_SCTP)
146 				m->m_pkthdr.csum_flags |= CSUM_SCTP_VALID;
147 #endif
148 			*error = netisr_queue(NETISR_IP, m);
149 			return 1; /* Finished */
150 		}
151 
152 		bzero(dst, sizeof(*dst));
153 		dst->sin_family = AF_INET;
154 		dst->sin_len = sizeof(*dst);
155 		dst->sin_addr = ip->ip_dst;
156 
157 		return -1; /* Reloop */
158 	}
159 	/* See if fib was changed by packet filter. */
160 	if ((*fibnum) != M_GETFIB(m)) {
161 		m->m_flags |= M_SKIP_FIREWALL;
162 		*fibnum = M_GETFIB(m);
163 		return -1; /* Reloop for FIB change */
164 	}
165 
166 	/* See if local, if yes, send it to netisr with IP_FASTFWD_OURS. */
167 	if (m->m_flags & M_FASTFWD_OURS) {
168 		if (m->m_pkthdr.rcvif == NULL)
169 			m->m_pkthdr.rcvif = V_loif;
170 		if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
171 			m->m_pkthdr.csum_flags |=
172 				CSUM_DATA_VALID | CSUM_PSEUDO_HDR;
173 			m->m_pkthdr.csum_data = 0xffff;
174 		}
175 #ifdef SCTP
176 		if (m->m_pkthdr.csum_flags & CSUM_SCTP)
177 			m->m_pkthdr.csum_flags |= CSUM_SCTP_VALID;
178 #endif
179 		m->m_pkthdr.csum_flags |=
180 			CSUM_IP_CHECKED | CSUM_IP_VALID;
181 
182 		*error = netisr_queue(NETISR_IP, m);
183 		return 1; /* Finished */
184 	}
185 	/* Or forward to some other address? */
186 	if ((m->m_flags & M_IP_NEXTHOP) &&
187 	    ((fwd_tag = m_tag_find(m, PACKET_TAG_IPFORWARD, NULL)) != NULL)) {
188 		bcopy((fwd_tag+1), dst, sizeof(struct sockaddr_in));
189 		m->m_flags |= M_SKIP_FIREWALL;
190 		m->m_flags &= ~M_IP_NEXTHOP;
191 		m_tag_delete(m, fwd_tag);
192 
193 		return -1; /* Reloop for CHANGE of dst */
194 	}
195 
196 	return 0;
197 }
198 
199 /*
200  * IP output.  The packet in mbuf chain m contains a skeletal IP
201  * header (with len, off, ttl, proto, tos, src, dst).
202  * The mbuf chain containing the packet will be freed.
203  * The mbuf opt, if present, will not be freed.
204  * If route ro is present and has ro_rt initialized, route lookup would be
205  * skipped and ro->ro_rt would be used. If ro is present but ro->ro_rt is NULL,
206  * then result of route lookup is stored in ro->ro_rt.
207  *
208  * In the IP forwarding case, the packet will arrive with options already
209  * inserted, so must have a NULL opt pointer.
210  */
211 int
212 ip_output(struct mbuf *m, struct mbuf *opt, struct route *ro, int flags,
213     struct ip_moptions *imo, struct inpcb *inp)
214 {
215 	struct rm_priotracker in_ifa_tracker;
216 	struct ip *ip;
217 	struct ifnet *ifp = NULL;	/* keep compiler happy */
218 	struct mbuf *m0;
219 	int hlen = sizeof (struct ip);
220 	int mtu;
221 	int error = 0;
222 	struct sockaddr_in *dst;
223 	const struct sockaddr_in *gw;
224 	struct in_ifaddr *ia;
225 	int isbroadcast;
226 	uint16_t ip_len, ip_off;
227 	struct route iproute;
228 	struct rtentry *rte;	/* cache for ro->ro_rt */
229 	uint32_t fibnum;
230 	int have_ia_ref;
231 #ifdef IPSEC
232 	int no_route_but_check_spd = 0;
233 #endif
234 	M_ASSERTPKTHDR(m);
235 
236 	if (inp != NULL) {
237 		INP_LOCK_ASSERT(inp);
238 		M_SETFIB(m, inp->inp_inc.inc_fibnum);
239 		if ((flags & IP_NODEFAULTFLOWID) == 0) {
240 			m->m_pkthdr.flowid = inp->inp_flowid;
241 			M_HASHTYPE_SET(m, inp->inp_flowtype);
242 		}
243 	}
244 
245 	if (ro == NULL) {
246 		ro = &iproute;
247 		bzero(ro, sizeof (*ro));
248 	}
249 
250 #ifdef FLOWTABLE
251 	if (ro->ro_rt == NULL)
252 		(void )flowtable_lookup(AF_INET, m, ro);
253 #endif
254 
255 	if (opt) {
256 		int len = 0;
257 		m = ip_insertoptions(m, opt, &len);
258 		if (len != 0)
259 			hlen = len; /* ip->ip_hl is updated above */
260 	}
261 	ip = mtod(m, struct ip *);
262 	ip_len = ntohs(ip->ip_len);
263 	ip_off = ntohs(ip->ip_off);
264 
265 	if ((flags & (IP_FORWARDING|IP_RAWOUTPUT)) == 0) {
266 		ip->ip_v = IPVERSION;
267 		ip->ip_hl = hlen >> 2;
268 		ip_fillid(ip);
269 		IPSTAT_INC(ips_localout);
270 	} else {
271 		/* Header already set, fetch hlen from there */
272 		hlen = ip->ip_hl << 2;
273 	}
274 
275 	/*
276 	 * dst/gw handling:
277 	 *
278 	 * dst can be rewritten but always points to &ro->ro_dst.
279 	 * gw is readonly but can point either to dst OR rt_gateway,
280 	 * therefore we need restore gw if we're redoing lookup.
281 	 */
282 	gw = dst = (struct sockaddr_in *)&ro->ro_dst;
283 	fibnum = (inp != NULL) ? inp->inp_inc.inc_fibnum : M_GETFIB(m);
284 	rte = ro->ro_rt;
285 	/*
286 	 * The address family should also be checked in case of sharing
287 	 * the cache with IPv6.
288 	 */
289 	if (rte == NULL || dst->sin_family != AF_INET) {
290 		bzero(dst, sizeof(*dst));
291 		dst->sin_family = AF_INET;
292 		dst->sin_len = sizeof(*dst);
293 		dst->sin_addr = ip->ip_dst;
294 	}
295 again:
296 	ia = NULL;
297 	have_ia_ref = 0;
298 	/*
299 	 * If routing to interface only, short circuit routing lookup.
300 	 * The use of an all-ones broadcast address implies this; an
301 	 * interface is specified by the broadcast address of an interface,
302 	 * or the destination address of a ptp interface.
303 	 */
304 	if (flags & IP_SENDONES) {
305 		if ((ia = ifatoia(ifa_ifwithbroadaddr(sintosa(dst),
306 						      M_GETFIB(m)))) == NULL &&
307 		    (ia = ifatoia(ifa_ifwithdstaddr(sintosa(dst),
308 						    M_GETFIB(m)))) == NULL) {
309 			IPSTAT_INC(ips_noroute);
310 			error = ENETUNREACH;
311 			goto bad;
312 		}
313 		have_ia_ref = 1;
314 		ip->ip_dst.s_addr = INADDR_BROADCAST;
315 		dst->sin_addr = ip->ip_dst;
316 		ifp = ia->ia_ifp;
317 		ip->ip_ttl = 1;
318 		isbroadcast = 1;
319 	} else if (flags & IP_ROUTETOIF) {
320 		if ((ia = ifatoia(ifa_ifwithdstaddr(sintosa(dst),
321 						    M_GETFIB(m)))) == NULL &&
322 		    (ia = ifatoia(ifa_ifwithnet(sintosa(dst), 0,
323 						M_GETFIB(m)))) == NULL) {
324 			IPSTAT_INC(ips_noroute);
325 			error = ENETUNREACH;
326 			goto bad;
327 		}
328 		have_ia_ref = 1;
329 		ifp = ia->ia_ifp;
330 		ip->ip_ttl = 1;
331 		isbroadcast = in_broadcast(dst->sin_addr, ifp);
332 	} else if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr)) &&
333 	    imo != NULL && imo->imo_multicast_ifp != NULL) {
334 		/*
335 		 * Bypass the normal routing lookup for multicast
336 		 * packets if the interface is specified.
337 		 */
338 		ifp = imo->imo_multicast_ifp;
339 		IFP_TO_IA(ifp, ia, &in_ifa_tracker);
340 		if (ia)
341 			have_ia_ref = 1;
342 		isbroadcast = 0;	/* fool gcc */
343 	} else {
344 		/*
345 		 * We want to do any cloning requested by the link layer,
346 		 * as this is probably required in all cases for correct
347 		 * operation (as it is for ARP).
348 		 */
349 		if (rte == NULL) {
350 #ifdef RADIX_MPATH
351 			rtalloc_mpath_fib(ro,
352 			    ntohl(ip->ip_src.s_addr ^ ip->ip_dst.s_addr),
353 			    fibnum);
354 #else
355 			in_rtalloc_ign(ro, 0, fibnum);
356 #endif
357 			rte = ro->ro_rt;
358 		}
359 		if (rte == NULL ||
360 		    (rte->rt_flags & RTF_UP) == 0 ||
361 		    rte->rt_ifp == NULL ||
362 		    !RT_LINK_IS_UP(rte->rt_ifp)) {
363 #ifdef IPSEC
364 			/*
365 			 * There is no route for this packet, but it is
366 			 * possible that a matching SPD entry exists.
367 			 */
368 			no_route_but_check_spd = 1;
369 			mtu = 0; /* Silence GCC warning. */
370 			goto sendit;
371 #endif
372 			IPSTAT_INC(ips_noroute);
373 			error = EHOSTUNREACH;
374 			goto bad;
375 		}
376 		ia = ifatoia(rte->rt_ifa);
377 		ifp = rte->rt_ifp;
378 		counter_u64_add(rte->rt_pksent, 1);
379 		rt_update_ro_flags(ro);
380 		if (rte->rt_flags & RTF_GATEWAY)
381 			gw = (struct sockaddr_in *)rte->rt_gateway;
382 		if (rte->rt_flags & RTF_HOST)
383 			isbroadcast = (rte->rt_flags & RTF_BROADCAST);
384 		else
385 			isbroadcast = in_broadcast(gw->sin_addr, ifp);
386 	}
387 
388 	/*
389 	 * Calculate MTU.  If we have a route that is up, use that,
390 	 * otherwise use the interface's MTU.
391 	 */
392 	if (rte != NULL && (rte->rt_flags & (RTF_UP|RTF_HOST)))
393 		mtu = rte->rt_mtu;
394 	else
395 		mtu = ifp->if_mtu;
396 	/* Catch a possible divide by zero later. */
397 	KASSERT(mtu > 0, ("%s: mtu %d <= 0, rte=%p (rt_flags=0x%08x) ifp=%p",
398 	    __func__, mtu, rte, (rte != NULL) ? rte->rt_flags : 0, ifp));
399 
400 	if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) {
401 		m->m_flags |= M_MCAST;
402 		/*
403 		 * IP destination address is multicast.  Make sure "gw"
404 		 * still points to the address in "ro".  (It may have been
405 		 * changed to point to a gateway address, above.)
406 		 */
407 		gw = dst;
408 		/*
409 		 * See if the caller provided any multicast options
410 		 */
411 		if (imo != NULL) {
412 			ip->ip_ttl = imo->imo_multicast_ttl;
413 			if (imo->imo_multicast_vif != -1)
414 				ip->ip_src.s_addr =
415 				    ip_mcast_src ?
416 				    ip_mcast_src(imo->imo_multicast_vif) :
417 				    INADDR_ANY;
418 		} else
419 			ip->ip_ttl = IP_DEFAULT_MULTICAST_TTL;
420 		/*
421 		 * Confirm that the outgoing interface supports multicast.
422 		 */
423 		if ((imo == NULL) || (imo->imo_multicast_vif == -1)) {
424 			if ((ifp->if_flags & IFF_MULTICAST) == 0) {
425 				IPSTAT_INC(ips_noroute);
426 				error = ENETUNREACH;
427 				goto bad;
428 			}
429 		}
430 		/*
431 		 * If source address not specified yet, use address
432 		 * of outgoing interface.
433 		 */
434 		if (ip->ip_src.s_addr == INADDR_ANY) {
435 			/* Interface may have no addresses. */
436 			if (ia != NULL)
437 				ip->ip_src = IA_SIN(ia)->sin_addr;
438 		}
439 
440 		if ((imo == NULL && in_mcast_loop) ||
441 		    (imo && imo->imo_multicast_loop)) {
442 			/*
443 			 * Loop back multicast datagram if not expressly
444 			 * forbidden to do so, even if we are not a member
445 			 * of the group; ip_input() will filter it later,
446 			 * thus deferring a hash lookup and mutex acquisition
447 			 * at the expense of a cheap copy using m_copym().
448 			 */
449 			ip_mloopback(ifp, m, hlen);
450 		} else {
451 			/*
452 			 * If we are acting as a multicast router, perform
453 			 * multicast forwarding as if the packet had just
454 			 * arrived on the interface to which we are about
455 			 * to send.  The multicast forwarding function
456 			 * recursively calls this function, using the
457 			 * IP_FORWARDING flag to prevent infinite recursion.
458 			 *
459 			 * Multicasts that are looped back by ip_mloopback(),
460 			 * above, will be forwarded by the ip_input() routine,
461 			 * if necessary.
462 			 */
463 			if (V_ip_mrouter && (flags & IP_FORWARDING) == 0) {
464 				/*
465 				 * If rsvp daemon is not running, do not
466 				 * set ip_moptions. This ensures that the packet
467 				 * is multicast and not just sent down one link
468 				 * as prescribed by rsvpd.
469 				 */
470 				if (!V_rsvp_on)
471 					imo = NULL;
472 				if (ip_mforward &&
473 				    ip_mforward(ip, ifp, m, imo) != 0) {
474 					m_freem(m);
475 					goto done;
476 				}
477 			}
478 		}
479 
480 		/*
481 		 * Multicasts with a time-to-live of zero may be looped-
482 		 * back, above, but must not be transmitted on a network.
483 		 * Also, multicasts addressed to the loopback interface
484 		 * are not sent -- the above call to ip_mloopback() will
485 		 * loop back a copy. ip_input() will drop the copy if
486 		 * this host does not belong to the destination group on
487 		 * the loopback interface.
488 		 */
489 		if (ip->ip_ttl == 0 || ifp->if_flags & IFF_LOOPBACK) {
490 			m_freem(m);
491 			goto done;
492 		}
493 
494 		goto sendit;
495 	}
496 
497 	/*
498 	 * If the source address is not specified yet, use the address
499 	 * of the outoing interface.
500 	 */
501 	if (ip->ip_src.s_addr == INADDR_ANY) {
502 		/* Interface may have no addresses. */
503 		if (ia != NULL) {
504 			ip->ip_src = IA_SIN(ia)->sin_addr;
505 		}
506 	}
507 
508 	/*
509 	 * Look for broadcast address and
510 	 * verify user is allowed to send
511 	 * such a packet.
512 	 */
513 	if (isbroadcast) {
514 		if ((ifp->if_flags & IFF_BROADCAST) == 0) {
515 			error = EADDRNOTAVAIL;
516 			goto bad;
517 		}
518 		if ((flags & IP_ALLOWBROADCAST) == 0) {
519 			error = EACCES;
520 			goto bad;
521 		}
522 		/* don't allow broadcast messages to be fragmented */
523 		if (ip_len > mtu) {
524 			error = EMSGSIZE;
525 			goto bad;
526 		}
527 		m->m_flags |= M_BCAST;
528 	} else {
529 		m->m_flags &= ~M_BCAST;
530 	}
531 
532 sendit:
533 #ifdef IPSEC
534 	switch(ip_ipsec_output(&m, inp, &error)) {
535 	case 1:
536 		goto bad;
537 	case -1:
538 		goto done;
539 	case 0:
540 	default:
541 		break;	/* Continue with packet processing. */
542 	}
543 	/*
544 	 * Check if there was a route for this packet; return error if not.
545 	 */
546 	if (no_route_but_check_spd) {
547 		IPSTAT_INC(ips_noroute);
548 		error = EHOSTUNREACH;
549 		goto bad;
550 	}
551 	/* Update variables that are affected by ipsec4_output(). */
552 	ip = mtod(m, struct ip *);
553 	hlen = ip->ip_hl << 2;
554 #endif /* IPSEC */
555 
556 	/* Jump over all PFIL processing if hooks are not active. */
557 	if (PFIL_HOOKED(&V_inet_pfil_hook)) {
558 		switch (ip_output_pfil(&m, ifp, inp, dst, &fibnum, &error)) {
559 		case 1: /* Finished */
560 			goto done;
561 
562 		case 0: /* Continue normally */
563 			ip = mtod(m, struct ip *);
564 			break;
565 
566 		case -1: /* Need to try again */
567 			/* Reset everything for a new round */
568 			RO_RTFREE(ro);
569 			if (have_ia_ref)
570 				ifa_free(&ia->ia_ifa);
571 			ro->ro_prepend = NULL;
572 			rte = NULL;
573 			gw = dst;
574 			ip = mtod(m, struct ip *);
575 			goto again;
576 
577 		}
578 	}
579 
580 	/* 127/8 must not appear on wire - RFC1122. */
581 	if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET ||
582 	    (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) {
583 		if ((ifp->if_flags & IFF_LOOPBACK) == 0) {
584 			IPSTAT_INC(ips_badaddr);
585 			error = EADDRNOTAVAIL;
586 			goto bad;
587 		}
588 	}
589 
590 	m->m_pkthdr.csum_flags |= CSUM_IP;
591 	if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA & ~ifp->if_hwassist) {
592 		in_delayed_cksum(m);
593 		m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
594 	}
595 #ifdef SCTP
596 	if (m->m_pkthdr.csum_flags & CSUM_SCTP & ~ifp->if_hwassist) {
597 		sctp_delayed_cksum(m, (uint32_t)(ip->ip_hl << 2));
598 		m->m_pkthdr.csum_flags &= ~CSUM_SCTP;
599 	}
600 #endif
601 
602 	/*
603 	 * If small enough for interface, or the interface will take
604 	 * care of the fragmentation for us, we can just send directly.
605 	 */
606 	if (ip_len <= mtu ||
607 	    (m->m_pkthdr.csum_flags & ifp->if_hwassist & CSUM_TSO) != 0) {
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 				counter_u64_add(ia->ia_ifa.ifa_opackets,
623 				    m->m_pkthdr.len / m->m_pkthdr.tso_segsz);
624 			else
625 				counter_u64_add(ia->ia_ifa.ifa_opackets, 1);
626 
627 			counter_u64_add(ia->ia_ifa.ifa_obytes, m->m_pkthdr.len);
628 		}
629 #ifdef MBUF_STRESS_TEST
630 		if (mbuf_frag_size && m->m_pkthdr.len > mbuf_frag_size)
631 			m = m_fragment(m, M_NOWAIT, mbuf_frag_size);
632 #endif
633 		/*
634 		 * Reset layer specific mbuf flags
635 		 * to avoid confusing lower layers.
636 		 */
637 		m_clrprotoflags(m);
638 		IP_PROBE(send, NULL, NULL, ip, ifp, ip, NULL);
639 		error = (*ifp->if_output)(ifp, m,
640 		    (const struct sockaddr *)gw, ro);
641 		goto done;
642 	}
643 
644 	/* Balk when DF bit is set or the interface didn't support TSO. */
645 	if ((ip_off & IP_DF) || (m->m_pkthdr.csum_flags & CSUM_TSO)) {
646 		error = EMSGSIZE;
647 		IPSTAT_INC(ips_cantfrag);
648 		goto bad;
649 	}
650 
651 	/*
652 	 * Too large for interface; fragment if possible. If successful,
653 	 * on return, m will point to a list of packets to be sent.
654 	 */
655 	error = ip_fragment(ip, &m, mtu, ifp->if_hwassist);
656 	if (error)
657 		goto bad;
658 	for (; m; m = m0) {
659 		m0 = m->m_nextpkt;
660 		m->m_nextpkt = 0;
661 		if (error == 0) {
662 			/* Record statistics for this interface address. */
663 			if (ia != NULL) {
664 				counter_u64_add(ia->ia_ifa.ifa_opackets, 1);
665 				counter_u64_add(ia->ia_ifa.ifa_obytes,
666 				    m->m_pkthdr.len);
667 			}
668 			/*
669 			 * Reset layer specific mbuf flags
670 			 * to avoid confusing upper layers.
671 			 */
672 			m_clrprotoflags(m);
673 
674 			IP_PROBE(send, NULL, NULL, ip, ifp, ip, NULL);
675 			error = (*ifp->if_output)(ifp, m,
676 			    (const struct sockaddr *)gw, ro);
677 		} else
678 			m_freem(m);
679 	}
680 
681 	if (error == 0)
682 		IPSTAT_INC(ips_fragmented);
683 
684 done:
685 	if (ro == &iproute)
686 		RO_RTFREE(ro);
687 	else if (rte == NULL)
688 		/*
689 		 * If the caller supplied a route but somehow the reference
690 		 * to it has been released need to prevent the caller
691 		 * calling RTFREE on it again.
692 		 */
693 		ro->ro_rt = NULL;
694 	if (have_ia_ref)
695 		ifa_free(&ia->ia_ifa);
696 	return (error);
697 bad:
698 	m_freem(m);
699 	goto done;
700 }
701 
702 /*
703  * Create a chain of fragments which fit the given mtu. m_frag points to the
704  * mbuf to be fragmented; on return it points to the chain with the fragments.
705  * Return 0 if no error. If error, m_frag may contain a partially built
706  * chain of fragments that should be freed by the caller.
707  *
708  * if_hwassist_flags is the hw offload capabilities (see if_data.ifi_hwassist)
709  */
710 int
711 ip_fragment(struct ip *ip, struct mbuf **m_frag, int mtu,
712     u_long if_hwassist_flags)
713 {
714 	int error = 0;
715 	int hlen = ip->ip_hl << 2;
716 	int len = (mtu - hlen) & ~7;	/* size of payload in each fragment */
717 	int off;
718 	struct mbuf *m0 = *m_frag;	/* the original packet		*/
719 	int firstlen;
720 	struct mbuf **mnext;
721 	int nfrags;
722 	uint16_t ip_len, ip_off;
723 
724 	ip_len = ntohs(ip->ip_len);
725 	ip_off = ntohs(ip->ip_off);
726 
727 	if (ip_off & IP_DF) {	/* Fragmentation not allowed */
728 		IPSTAT_INC(ips_cantfrag);
729 		return EMSGSIZE;
730 	}
731 
732 	/*
733 	 * Must be able to put at least 8 bytes per fragment.
734 	 */
735 	if (len < 8)
736 		return EMSGSIZE;
737 
738 	/*
739 	 * If the interface will not calculate checksums on
740 	 * fragmented packets, then do it here.
741 	 */
742 	if (m0->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
743 		in_delayed_cksum(m0);
744 		m0->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
745 	}
746 #ifdef SCTP
747 	if (m0->m_pkthdr.csum_flags & CSUM_SCTP) {
748 		sctp_delayed_cksum(m0, hlen);
749 		m0->m_pkthdr.csum_flags &= ~CSUM_SCTP;
750 	}
751 #endif
752 	if (len > PAGE_SIZE) {
753 		/*
754 		 * Fragment large datagrams such that each segment
755 		 * contains a multiple of PAGE_SIZE amount of data,
756 		 * plus headers. This enables a receiver to perform
757 		 * page-flipping zero-copy optimizations.
758 		 *
759 		 * XXX When does this help given that sender and receiver
760 		 * could have different page sizes, and also mtu could
761 		 * be less than the receiver's page size ?
762 		 */
763 		int newlen;
764 
765 		off = MIN(mtu, m0->m_pkthdr.len);
766 
767 		/*
768 		 * firstlen (off - hlen) must be aligned on an
769 		 * 8-byte boundary
770 		 */
771 		if (off < hlen)
772 			goto smart_frag_failure;
773 		off = ((off - hlen) & ~7) + hlen;
774 		newlen = (~PAGE_MASK) & mtu;
775 		if ((newlen + sizeof (struct ip)) > mtu) {
776 			/* we failed, go back the default */
777 smart_frag_failure:
778 			newlen = len;
779 			off = hlen + len;
780 		}
781 		len = newlen;
782 
783 	} else {
784 		off = hlen + len;
785 	}
786 
787 	firstlen = off - hlen;
788 	mnext = &m0->m_nextpkt;		/* pointer to next packet */
789 
790 	/*
791 	 * Loop through length of segment after first fragment,
792 	 * make new header and copy data of each part and link onto chain.
793 	 * Here, m0 is the original packet, m is the fragment being created.
794 	 * The fragments are linked off the m_nextpkt of the original
795 	 * packet, which after processing serves as the first fragment.
796 	 */
797 	for (nfrags = 1; off < ip_len; off += len, nfrags++) {
798 		struct ip *mhip;	/* ip header on the fragment */
799 		struct mbuf *m;
800 		int mhlen = sizeof (struct ip);
801 
802 		m = m_gethdr(M_NOWAIT, MT_DATA);
803 		if (m == NULL) {
804 			error = ENOBUFS;
805 			IPSTAT_INC(ips_odropped);
806 			goto done;
807 		}
808 		/*
809 		 * Make sure the complete packet header gets copied
810 		 * from the originating mbuf to the newly created
811 		 * mbuf. This also ensures that existing firewall
812 		 * classification(s), VLAN tags and so on get copied
813 		 * to the resulting fragmented packet(s):
814 		 */
815 		if (m_dup_pkthdr(m, m0, M_NOWAIT) == 0) {
816 			m_free(m);
817 			error = ENOBUFS;
818 			IPSTAT_INC(ips_odropped);
819 			goto done;
820 		}
821 		/*
822 		 * In the first mbuf, leave room for the link header, then
823 		 * copy the original IP header including options. The payload
824 		 * goes into an additional mbuf chain returned by m_copym().
825 		 */
826 		m->m_data += max_linkhdr;
827 		mhip = mtod(m, struct ip *);
828 		*mhip = *ip;
829 		if (hlen > sizeof (struct ip)) {
830 			mhlen = ip_optcopy(ip, mhip) + sizeof (struct ip);
831 			mhip->ip_v = IPVERSION;
832 			mhip->ip_hl = mhlen >> 2;
833 		}
834 		m->m_len = mhlen;
835 		/* XXX do we need to add ip_off below ? */
836 		mhip->ip_off = ((off - hlen) >> 3) + ip_off;
837 		if (off + len >= ip_len)
838 			len = ip_len - off;
839 		else
840 			mhip->ip_off |= IP_MF;
841 		mhip->ip_len = htons((u_short)(len + mhlen));
842 		m->m_next = m_copym(m0, off, len, M_NOWAIT);
843 		if (m->m_next == NULL) {	/* copy failed */
844 			m_free(m);
845 			error = ENOBUFS;	/* ??? */
846 			IPSTAT_INC(ips_odropped);
847 			goto done;
848 		}
849 		m->m_pkthdr.len = mhlen + len;
850 #ifdef MAC
851 		mac_netinet_fragment(m0, m);
852 #endif
853 		mhip->ip_off = htons(mhip->ip_off);
854 		mhip->ip_sum = 0;
855 		if (m->m_pkthdr.csum_flags & CSUM_IP & ~if_hwassist_flags) {
856 			mhip->ip_sum = in_cksum(m, mhlen);
857 			m->m_pkthdr.csum_flags &= ~CSUM_IP;
858 		}
859 		*mnext = m;
860 		mnext = &m->m_nextpkt;
861 	}
862 	IPSTAT_ADD(ips_ofragments, nfrags);
863 
864 	/*
865 	 * Update first fragment by trimming what's been copied out
866 	 * and updating header.
867 	 */
868 	m_adj(m0, hlen + firstlen - ip_len);
869 	m0->m_pkthdr.len = hlen + firstlen;
870 	ip->ip_len = htons((u_short)m0->m_pkthdr.len);
871 	ip->ip_off = htons(ip_off | IP_MF);
872 	ip->ip_sum = 0;
873 	if (m0->m_pkthdr.csum_flags & CSUM_IP & ~if_hwassist_flags) {
874 		ip->ip_sum = in_cksum(m0, hlen);
875 		m0->m_pkthdr.csum_flags &= ~CSUM_IP;
876 	}
877 
878 done:
879 	*m_frag = m0;
880 	return error;
881 }
882 
883 void
884 in_delayed_cksum(struct mbuf *m)
885 {
886 	struct ip *ip;
887 	uint16_t csum, offset, ip_len;
888 
889 	ip = mtod(m, struct ip *);
890 	offset = ip->ip_hl << 2 ;
891 	ip_len = ntohs(ip->ip_len);
892 	csum = in_cksum_skip(m, ip_len, offset);
893 	if (m->m_pkthdr.csum_flags & CSUM_UDP && csum == 0)
894 		csum = 0xffff;
895 	offset += m->m_pkthdr.csum_data;	/* checksum offset */
896 
897 	/* find the mbuf in the chain where the checksum starts*/
898 	while ((m != NULL) && (offset >= m->m_len)) {
899 		offset -= m->m_len;
900 		m = m->m_next;
901 	}
902 	KASSERT(m != NULL, ("in_delayed_cksum: checksum outside mbuf chain."));
903 	KASSERT(offset + sizeof(u_short) <= m->m_len, ("in_delayed_cksum: checksum split between mbufs."));
904 	*(u_short *)(m->m_data + offset) = csum;
905 }
906 
907 /*
908  * IP socket option processing.
909  */
910 int
911 ip_ctloutput(struct socket *so, struct sockopt *sopt)
912 {
913 	struct	inpcb *inp = sotoinpcb(so);
914 	int	error, optval;
915 #ifdef	RSS
916 	uint32_t rss_bucket;
917 	int retval;
918 #endif
919 
920 	error = optval = 0;
921 	if (sopt->sopt_level != IPPROTO_IP) {
922 		error = EINVAL;
923 
924 		if (sopt->sopt_level == SOL_SOCKET &&
925 		    sopt->sopt_dir == SOPT_SET) {
926 			switch (sopt->sopt_name) {
927 			case SO_REUSEADDR:
928 				INP_WLOCK(inp);
929 				if ((so->so_options & SO_REUSEADDR) != 0)
930 					inp->inp_flags2 |= INP_REUSEADDR;
931 				else
932 					inp->inp_flags2 &= ~INP_REUSEADDR;
933 				INP_WUNLOCK(inp);
934 				error = 0;
935 				break;
936 			case SO_REUSEPORT:
937 				INP_WLOCK(inp);
938 				if ((so->so_options & SO_REUSEPORT) != 0)
939 					inp->inp_flags2 |= INP_REUSEPORT;
940 				else
941 					inp->inp_flags2 &= ~INP_REUSEPORT;
942 				INP_WUNLOCK(inp);
943 				error = 0;
944 				break;
945 			case SO_SETFIB:
946 				INP_WLOCK(inp);
947 				inp->inp_inc.inc_fibnum = so->so_fibnum;
948 				INP_WUNLOCK(inp);
949 				error = 0;
950 				break;
951 			default:
952 				break;
953 			}
954 		}
955 		return (error);
956 	}
957 
958 	switch (sopt->sopt_dir) {
959 	case SOPT_SET:
960 		switch (sopt->sopt_name) {
961 		case IP_OPTIONS:
962 #ifdef notyet
963 		case IP_RETOPTS:
964 #endif
965 		{
966 			struct mbuf *m;
967 			if (sopt->sopt_valsize > MLEN) {
968 				error = EMSGSIZE;
969 				break;
970 			}
971 			m = m_get(sopt->sopt_td ? M_WAITOK : M_NOWAIT, MT_DATA);
972 			if (m == NULL) {
973 				error = ENOBUFS;
974 				break;
975 			}
976 			m->m_len = sopt->sopt_valsize;
977 			error = sooptcopyin(sopt, mtod(m, char *), m->m_len,
978 					    m->m_len);
979 			if (error) {
980 				m_free(m);
981 				break;
982 			}
983 			INP_WLOCK(inp);
984 			error = ip_pcbopts(inp, sopt->sopt_name, m);
985 			INP_WUNLOCK(inp);
986 			return (error);
987 		}
988 
989 		case IP_BINDANY:
990 			if (sopt->sopt_td != NULL) {
991 				error = priv_check(sopt->sopt_td,
992 				    PRIV_NETINET_BINDANY);
993 				if (error)
994 					break;
995 			}
996 			/* FALLTHROUGH */
997 		case IP_BINDMULTI:
998 #ifdef	RSS
999 		case IP_RSS_LISTEN_BUCKET:
1000 #endif
1001 		case IP_TOS:
1002 		case IP_TTL:
1003 		case IP_MINTTL:
1004 		case IP_RECVOPTS:
1005 		case IP_RECVRETOPTS:
1006 		case IP_RECVDSTADDR:
1007 		case IP_RECVTTL:
1008 		case IP_RECVIF:
1009 		case IP_ONESBCAST:
1010 		case IP_DONTFRAG:
1011 		case IP_RECVTOS:
1012 		case IP_RECVFLOWID:
1013 #ifdef	RSS
1014 		case IP_RECVRSSBUCKETID:
1015 #endif
1016 			error = sooptcopyin(sopt, &optval, sizeof optval,
1017 					    sizeof optval);
1018 			if (error)
1019 				break;
1020 
1021 			switch (sopt->sopt_name) {
1022 			case IP_TOS:
1023 				inp->inp_ip_tos = optval;
1024 				break;
1025 
1026 			case IP_TTL:
1027 				inp->inp_ip_ttl = optval;
1028 				break;
1029 
1030 			case IP_MINTTL:
1031 				if (optval >= 0 && optval <= MAXTTL)
1032 					inp->inp_ip_minttl = optval;
1033 				else
1034 					error = EINVAL;
1035 				break;
1036 
1037 #define	OPTSET(bit) do {						\
1038 	INP_WLOCK(inp);							\
1039 	if (optval)							\
1040 		inp->inp_flags |= bit;					\
1041 	else								\
1042 		inp->inp_flags &= ~bit;					\
1043 	INP_WUNLOCK(inp);						\
1044 } while (0)
1045 
1046 #define	OPTSET2(bit, val) do {						\
1047 	INP_WLOCK(inp);							\
1048 	if (val)							\
1049 		inp->inp_flags2 |= bit;					\
1050 	else								\
1051 		inp->inp_flags2 &= ~bit;				\
1052 	INP_WUNLOCK(inp);						\
1053 } while (0)
1054 
1055 			case IP_RECVOPTS:
1056 				OPTSET(INP_RECVOPTS);
1057 				break;
1058 
1059 			case IP_RECVRETOPTS:
1060 				OPTSET(INP_RECVRETOPTS);
1061 				break;
1062 
1063 			case IP_RECVDSTADDR:
1064 				OPTSET(INP_RECVDSTADDR);
1065 				break;
1066 
1067 			case IP_RECVTTL:
1068 				OPTSET(INP_RECVTTL);
1069 				break;
1070 
1071 			case IP_RECVIF:
1072 				OPTSET(INP_RECVIF);
1073 				break;
1074 
1075 			case IP_ONESBCAST:
1076 				OPTSET(INP_ONESBCAST);
1077 				break;
1078 			case IP_DONTFRAG:
1079 				OPTSET(INP_DONTFRAG);
1080 				break;
1081 			case IP_BINDANY:
1082 				OPTSET(INP_BINDANY);
1083 				break;
1084 			case IP_RECVTOS:
1085 				OPTSET(INP_RECVTOS);
1086 				break;
1087 			case IP_BINDMULTI:
1088 				OPTSET2(INP_BINDMULTI, optval);
1089 				break;
1090 			case IP_RECVFLOWID:
1091 				OPTSET2(INP_RECVFLOWID, optval);
1092 				break;
1093 #ifdef	RSS
1094 			case IP_RSS_LISTEN_BUCKET:
1095 				if ((optval >= 0) &&
1096 				    (optval < rss_getnumbuckets())) {
1097 					inp->inp_rss_listen_bucket = optval;
1098 					OPTSET2(INP_RSS_BUCKET_SET, 1);
1099 				} else {
1100 					error = EINVAL;
1101 				}
1102 				break;
1103 			case IP_RECVRSSBUCKETID:
1104 				OPTSET2(INP_RECVRSSBUCKETID, optval);
1105 				break;
1106 #endif
1107 			}
1108 			break;
1109 #undef OPTSET
1110 #undef OPTSET2
1111 
1112 		/*
1113 		 * Multicast socket options are processed by the in_mcast
1114 		 * module.
1115 		 */
1116 		case IP_MULTICAST_IF:
1117 		case IP_MULTICAST_VIF:
1118 		case IP_MULTICAST_TTL:
1119 		case IP_MULTICAST_LOOP:
1120 		case IP_ADD_MEMBERSHIP:
1121 		case IP_DROP_MEMBERSHIP:
1122 		case IP_ADD_SOURCE_MEMBERSHIP:
1123 		case IP_DROP_SOURCE_MEMBERSHIP:
1124 		case IP_BLOCK_SOURCE:
1125 		case IP_UNBLOCK_SOURCE:
1126 		case IP_MSFILTER:
1127 		case MCAST_JOIN_GROUP:
1128 		case MCAST_LEAVE_GROUP:
1129 		case MCAST_JOIN_SOURCE_GROUP:
1130 		case MCAST_LEAVE_SOURCE_GROUP:
1131 		case MCAST_BLOCK_SOURCE:
1132 		case MCAST_UNBLOCK_SOURCE:
1133 			error = inp_setmoptions(inp, sopt);
1134 			break;
1135 
1136 		case IP_PORTRANGE:
1137 			error = sooptcopyin(sopt, &optval, sizeof optval,
1138 					    sizeof optval);
1139 			if (error)
1140 				break;
1141 
1142 			INP_WLOCK(inp);
1143 			switch (optval) {
1144 			case IP_PORTRANGE_DEFAULT:
1145 				inp->inp_flags &= ~(INP_LOWPORT);
1146 				inp->inp_flags &= ~(INP_HIGHPORT);
1147 				break;
1148 
1149 			case IP_PORTRANGE_HIGH:
1150 				inp->inp_flags &= ~(INP_LOWPORT);
1151 				inp->inp_flags |= INP_HIGHPORT;
1152 				break;
1153 
1154 			case IP_PORTRANGE_LOW:
1155 				inp->inp_flags &= ~(INP_HIGHPORT);
1156 				inp->inp_flags |= INP_LOWPORT;
1157 				break;
1158 
1159 			default:
1160 				error = EINVAL;
1161 				break;
1162 			}
1163 			INP_WUNLOCK(inp);
1164 			break;
1165 
1166 #ifdef IPSEC
1167 		case IP_IPSEC_POLICY:
1168 		{
1169 			caddr_t req;
1170 			struct mbuf *m;
1171 
1172 			if ((error = soopt_getm(sopt, &m)) != 0) /* XXX */
1173 				break;
1174 			if ((error = soopt_mcopyin(sopt, m)) != 0) /* XXX */
1175 				break;
1176 			req = mtod(m, caddr_t);
1177 			error = ipsec_set_policy(inp, sopt->sopt_name, req,
1178 			    m->m_len, (sopt->sopt_td != NULL) ?
1179 			    sopt->sopt_td->td_ucred : NULL);
1180 			m_freem(m);
1181 			break;
1182 		}
1183 #endif /* IPSEC */
1184 
1185 		default:
1186 			error = ENOPROTOOPT;
1187 			break;
1188 		}
1189 		break;
1190 
1191 	case SOPT_GET:
1192 		switch (sopt->sopt_name) {
1193 		case IP_OPTIONS:
1194 		case IP_RETOPTS:
1195 			if (inp->inp_options)
1196 				error = sooptcopyout(sopt,
1197 						     mtod(inp->inp_options,
1198 							  char *),
1199 						     inp->inp_options->m_len);
1200 			else
1201 				sopt->sopt_valsize = 0;
1202 			break;
1203 
1204 		case IP_TOS:
1205 		case IP_TTL:
1206 		case IP_MINTTL:
1207 		case IP_RECVOPTS:
1208 		case IP_RECVRETOPTS:
1209 		case IP_RECVDSTADDR:
1210 		case IP_RECVTTL:
1211 		case IP_RECVIF:
1212 		case IP_PORTRANGE:
1213 		case IP_ONESBCAST:
1214 		case IP_DONTFRAG:
1215 		case IP_BINDANY:
1216 		case IP_RECVTOS:
1217 		case IP_BINDMULTI:
1218 		case IP_FLOWID:
1219 		case IP_FLOWTYPE:
1220 		case IP_RECVFLOWID:
1221 #ifdef	RSS
1222 		case IP_RSSBUCKETID:
1223 		case IP_RECVRSSBUCKETID:
1224 #endif
1225 			switch (sopt->sopt_name) {
1226 
1227 			case IP_TOS:
1228 				optval = inp->inp_ip_tos;
1229 				break;
1230 
1231 			case IP_TTL:
1232 				optval = inp->inp_ip_ttl;
1233 				break;
1234 
1235 			case IP_MINTTL:
1236 				optval = inp->inp_ip_minttl;
1237 				break;
1238 
1239 #define	OPTBIT(bit)	(inp->inp_flags & bit ? 1 : 0)
1240 #define	OPTBIT2(bit)	(inp->inp_flags2 & bit ? 1 : 0)
1241 
1242 			case IP_RECVOPTS:
1243 				optval = OPTBIT(INP_RECVOPTS);
1244 				break;
1245 
1246 			case IP_RECVRETOPTS:
1247 				optval = OPTBIT(INP_RECVRETOPTS);
1248 				break;
1249 
1250 			case IP_RECVDSTADDR:
1251 				optval = OPTBIT(INP_RECVDSTADDR);
1252 				break;
1253 
1254 			case IP_RECVTTL:
1255 				optval = OPTBIT(INP_RECVTTL);
1256 				break;
1257 
1258 			case IP_RECVIF:
1259 				optval = OPTBIT(INP_RECVIF);
1260 				break;
1261 
1262 			case IP_PORTRANGE:
1263 				if (inp->inp_flags & INP_HIGHPORT)
1264 					optval = IP_PORTRANGE_HIGH;
1265 				else if (inp->inp_flags & INP_LOWPORT)
1266 					optval = IP_PORTRANGE_LOW;
1267 				else
1268 					optval = 0;
1269 				break;
1270 
1271 			case IP_ONESBCAST:
1272 				optval = OPTBIT(INP_ONESBCAST);
1273 				break;
1274 			case IP_DONTFRAG:
1275 				optval = OPTBIT(INP_DONTFRAG);
1276 				break;
1277 			case IP_BINDANY:
1278 				optval = OPTBIT(INP_BINDANY);
1279 				break;
1280 			case IP_RECVTOS:
1281 				optval = OPTBIT(INP_RECVTOS);
1282 				break;
1283 			case IP_FLOWID:
1284 				optval = inp->inp_flowid;
1285 				break;
1286 			case IP_FLOWTYPE:
1287 				optval = inp->inp_flowtype;
1288 				break;
1289 			case IP_RECVFLOWID:
1290 				optval = OPTBIT2(INP_RECVFLOWID);
1291 				break;
1292 #ifdef	RSS
1293 			case IP_RSSBUCKETID:
1294 				retval = rss_hash2bucket(inp->inp_flowid,
1295 				    inp->inp_flowtype,
1296 				    &rss_bucket);
1297 				if (retval == 0)
1298 					optval = rss_bucket;
1299 				else
1300 					error = EINVAL;
1301 				break;
1302 			case IP_RECVRSSBUCKETID:
1303 				optval = OPTBIT2(INP_RECVRSSBUCKETID);
1304 				break;
1305 #endif
1306 			case IP_BINDMULTI:
1307 				optval = OPTBIT2(INP_BINDMULTI);
1308 				break;
1309 			}
1310 			error = sooptcopyout(sopt, &optval, sizeof optval);
1311 			break;
1312 
1313 		/*
1314 		 * Multicast socket options are processed by the in_mcast
1315 		 * module.
1316 		 */
1317 		case IP_MULTICAST_IF:
1318 		case IP_MULTICAST_VIF:
1319 		case IP_MULTICAST_TTL:
1320 		case IP_MULTICAST_LOOP:
1321 		case IP_MSFILTER:
1322 			error = inp_getmoptions(inp, sopt);
1323 			break;
1324 
1325 #ifdef IPSEC
1326 		case IP_IPSEC_POLICY:
1327 		{
1328 			struct mbuf *m = NULL;
1329 			caddr_t req = NULL;
1330 			size_t len = 0;
1331 
1332 			if (m != 0) {
1333 				req = mtod(m, caddr_t);
1334 				len = m->m_len;
1335 			}
1336 			error = ipsec_get_policy(sotoinpcb(so), req, len, &m);
1337 			if (error == 0)
1338 				error = soopt_mcopyout(sopt, m); /* XXX */
1339 			if (error == 0)
1340 				m_freem(m);
1341 			break;
1342 		}
1343 #endif /* IPSEC */
1344 
1345 		default:
1346 			error = ENOPROTOOPT;
1347 			break;
1348 		}
1349 		break;
1350 	}
1351 	return (error);
1352 }
1353 
1354 /*
1355  * Routine called from ip_output() to loop back a copy of an IP multicast
1356  * packet to the input queue of a specified interface.  Note that this
1357  * calls the output routine of the loopback "driver", but with an interface
1358  * pointer that might NOT be a loopback interface -- evil, but easier than
1359  * replicating that code here.
1360  */
1361 static void
1362 ip_mloopback(struct ifnet *ifp, const struct mbuf *m, int hlen)
1363 {
1364 	struct ip *ip;
1365 	struct mbuf *copym;
1366 
1367 	/*
1368 	 * Make a deep copy of the packet because we're going to
1369 	 * modify the pack in order to generate checksums.
1370 	 */
1371 	copym = m_dup(m, M_NOWAIT);
1372 	if (copym != NULL && (!M_WRITABLE(copym) || copym->m_len < hlen))
1373 		copym = m_pullup(copym, hlen);
1374 	if (copym != NULL) {
1375 		/* If needed, compute the checksum and mark it as valid. */
1376 		if (copym->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
1377 			in_delayed_cksum(copym);
1378 			copym->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
1379 			copym->m_pkthdr.csum_flags |=
1380 			    CSUM_DATA_VALID | CSUM_PSEUDO_HDR;
1381 			copym->m_pkthdr.csum_data = 0xffff;
1382 		}
1383 		/*
1384 		 * We don't bother to fragment if the IP length is greater
1385 		 * than the interface's MTU.  Can this possibly matter?
1386 		 */
1387 		ip = mtod(copym, struct ip *);
1388 		ip->ip_sum = 0;
1389 		ip->ip_sum = in_cksum(copym, hlen);
1390 		if_simloop(ifp, copym, AF_INET, 0);
1391 	}
1392 }
1393