xref: /freebsd/sys/netinet/ip_output.c (revision 206b73d0)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 1982, 1986, 1988, 1990, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. Neither the name of the University nor the names of its contributors
16  *    may be used to endorse or promote products derived from this software
17  *    without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  *
31  *	@(#)ip_output.c	8.3 (Berkeley) 1/21/94
32  */
33 
34 #include <sys/cdefs.h>
35 __FBSDID("$FreeBSD$");
36 
37 #include "opt_inet.h"
38 #include "opt_ipsec.h"
39 #include "opt_mbuf_stress_test.h"
40 #include "opt_mpath.h"
41 #include "opt_ratelimit.h"
42 #include "opt_route.h"
43 #include "opt_rss.h"
44 #include "opt_sctp.h"
45 
46 #include <sys/param.h>
47 #include <sys/systm.h>
48 #include <sys/kernel.h>
49 #include <sys/lock.h>
50 #include <sys/malloc.h>
51 #include <sys/mbuf.h>
52 #include <sys/priv.h>
53 #include <sys/proc.h>
54 #include <sys/protosw.h>
55 #include <sys/rmlock.h>
56 #include <sys/sdt.h>
57 #include <sys/socket.h>
58 #include <sys/socketvar.h>
59 #include <sys/sysctl.h>
60 #include <sys/ucred.h>
61 
62 #include <net/if.h>
63 #include <net/if_var.h>
64 #include <net/if_llatbl.h>
65 #include <net/netisr.h>
66 #include <net/pfil.h>
67 #include <net/route.h>
68 #ifdef RADIX_MPATH
69 #include <net/radix_mpath.h>
70 #endif
71 #include <net/rss_config.h>
72 #include <net/vnet.h>
73 
74 #include <netinet/in.h>
75 #include <netinet/in_fib.h>
76 #include <netinet/in_kdtrace.h>
77 #include <netinet/in_systm.h>
78 #include <netinet/ip.h>
79 #include <netinet/in_pcb.h>
80 #include <netinet/in_rss.h>
81 #include <netinet/in_var.h>
82 #include <netinet/ip_var.h>
83 #include <netinet/ip_options.h>
84 
85 #include <netinet/udp.h>
86 #include <netinet/udp_var.h>
87 
88 #ifdef SCTP
89 #include <netinet/sctp.h>
90 #include <netinet/sctp_crc32.h>
91 #endif
92 
93 #include <netipsec/ipsec_support.h>
94 
95 #include <machine/in_cksum.h>
96 
97 #include <security/mac/mac_framework.h>
98 
99 #ifdef MBUF_STRESS_TEST
100 static int mbuf_frag_size = 0;
101 SYSCTL_INT(_net_inet_ip, OID_AUTO, mbuf_frag_size, CTLFLAG_RW,
102 	&mbuf_frag_size, 0, "Fragment outgoing mbufs to this size");
103 #endif
104 
105 static void	ip_mloopback(struct ifnet *, const struct mbuf *, int);
106 
107 
108 extern int in_mcast_loop;
109 extern	struct protosw inetsw[];
110 
111 static inline int
112 ip_output_pfil(struct mbuf **mp, struct ifnet *ifp, int flags,
113     struct inpcb *inp, struct sockaddr_in *dst, int *fibnum, int *error)
114 {
115 	struct m_tag *fwd_tag = NULL;
116 	struct mbuf *m;
117 	struct in_addr odst;
118 	struct ip *ip;
119 	int pflags = PFIL_OUT;
120 
121 	if (flags & IP_FORWARDING)
122 		pflags |= PFIL_FWD;
123 
124 	m = *mp;
125 	ip = mtod(m, struct ip *);
126 
127 	/* Run through list of hooks for output packets. */
128 	odst.s_addr = ip->ip_dst.s_addr;
129 	switch (pfil_run_hooks(V_inet_pfil_head, mp, ifp, pflags, inp)) {
130 	case PFIL_DROPPED:
131 		*error = EPERM;
132 		/* FALLTHROUGH */
133 	case PFIL_CONSUMED:
134 		return 1; /* Finished */
135 	case PFIL_PASS:
136 		*error = 0;
137 	}
138 	m = *mp;
139 	ip = mtod(m, struct ip *);
140 
141 	/* See if destination IP address was changed by packet filter. */
142 	if (odst.s_addr != ip->ip_dst.s_addr) {
143 		m->m_flags |= M_SKIP_FIREWALL;
144 		/* If destination is now ourself drop to ip_input(). */
145 		if (in_localip(ip->ip_dst)) {
146 			m->m_flags |= M_FASTFWD_OURS;
147 			if (m->m_pkthdr.rcvif == NULL)
148 				m->m_pkthdr.rcvif = V_loif;
149 			if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
150 				m->m_pkthdr.csum_flags |=
151 					CSUM_DATA_VALID | CSUM_PSEUDO_HDR;
152 				m->m_pkthdr.csum_data = 0xffff;
153 			}
154 			m->m_pkthdr.csum_flags |=
155 				CSUM_IP_CHECKED | CSUM_IP_VALID;
156 #ifdef SCTP
157 			if (m->m_pkthdr.csum_flags & CSUM_SCTP)
158 				m->m_pkthdr.csum_flags |= CSUM_SCTP_VALID;
159 #endif
160 			*error = netisr_queue(NETISR_IP, m);
161 			return 1; /* Finished */
162 		}
163 
164 		bzero(dst, sizeof(*dst));
165 		dst->sin_family = AF_INET;
166 		dst->sin_len = sizeof(*dst);
167 		dst->sin_addr = ip->ip_dst;
168 
169 		return -1; /* Reloop */
170 	}
171 	/* See if fib was changed by packet filter. */
172 	if ((*fibnum) != M_GETFIB(m)) {
173 		m->m_flags |= M_SKIP_FIREWALL;
174 		*fibnum = M_GETFIB(m);
175 		return -1; /* Reloop for FIB change */
176 	}
177 
178 	/* See if local, if yes, send it to netisr with IP_FASTFWD_OURS. */
179 	if (m->m_flags & M_FASTFWD_OURS) {
180 		if (m->m_pkthdr.rcvif == NULL)
181 			m->m_pkthdr.rcvif = V_loif;
182 		if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
183 			m->m_pkthdr.csum_flags |=
184 				CSUM_DATA_VALID | CSUM_PSEUDO_HDR;
185 			m->m_pkthdr.csum_data = 0xffff;
186 		}
187 #ifdef SCTP
188 		if (m->m_pkthdr.csum_flags & CSUM_SCTP)
189 			m->m_pkthdr.csum_flags |= CSUM_SCTP_VALID;
190 #endif
191 		m->m_pkthdr.csum_flags |=
192 			CSUM_IP_CHECKED | CSUM_IP_VALID;
193 
194 		*error = netisr_queue(NETISR_IP, m);
195 		return 1; /* Finished */
196 	}
197 	/* Or forward to some other address? */
198 	if ((m->m_flags & M_IP_NEXTHOP) &&
199 	    ((fwd_tag = m_tag_find(m, PACKET_TAG_IPFORWARD, NULL)) != NULL)) {
200 		bcopy((fwd_tag+1), dst, sizeof(struct sockaddr_in));
201 		m->m_flags |= M_SKIP_FIREWALL;
202 		m->m_flags &= ~M_IP_NEXTHOP;
203 		m_tag_delete(m, fwd_tag);
204 
205 		return -1; /* Reloop for CHANGE of dst */
206 	}
207 
208 	return 0;
209 }
210 
211 static int
212 ip_output_send(struct inpcb *inp, struct ifnet *ifp, struct mbuf *m,
213     const struct sockaddr_in *gw, struct route *ro)
214 {
215 	struct m_snd_tag *mst;
216 	int error;
217 
218 	MPASS((m->m_pkthdr.csum_flags & CSUM_SND_TAG) == 0);
219 	mst = NULL;
220 
221 #ifdef RATELIMIT
222 	if (inp != NULL) {
223 		if ((inp->inp_flags2 & INP_RATE_LIMIT_CHANGED) != 0 ||
224 		    (inp->inp_snd_tag != NULL &&
225 		    inp->inp_snd_tag->ifp != ifp))
226 			in_pcboutput_txrtlmt(inp, ifp, m);
227 
228 		if (inp->inp_snd_tag != NULL)
229 			mst = inp->inp_snd_tag;
230 	}
231 #endif
232 	if (mst != NULL) {
233 		KASSERT(m->m_pkthdr.rcvif == NULL,
234 		    ("trying to add a send tag to a forwarded packet"));
235 		if (mst->ifp != ifp) {
236 			error = EAGAIN;
237 			goto done;
238 		}
239 
240 		/* stamp send tag on mbuf */
241 		m->m_pkthdr.snd_tag = m_snd_tag_ref(mst);
242 		m->m_pkthdr.csum_flags |= CSUM_SND_TAG;
243 	}
244 
245 	error = (*ifp->if_output)(ifp, m, (const struct sockaddr *)gw, ro);
246 
247 done:
248 	/* Check for route change invalidating send tags. */
249 #ifdef RATELIMIT
250 	if (error == EAGAIN)
251 		in_pcboutput_eagain(inp);
252 #endif
253 	return (error);
254 }
255 
256 /*
257  * IP output.  The packet in mbuf chain m contains a skeletal IP
258  * header (with len, off, ttl, proto, tos, src, dst).
259  * The mbuf chain containing the packet will be freed.
260  * The mbuf opt, if present, will not be freed.
261  * If route ro is present and has ro_rt initialized, route lookup would be
262  * skipped and ro->ro_rt would be used. If ro is present but ro->ro_rt is NULL,
263  * then result of route lookup is stored in ro->ro_rt.
264  *
265  * In the IP forwarding case, the packet will arrive with options already
266  * inserted, so must have a NULL opt pointer.
267  */
268 int
269 ip_output(struct mbuf *m, struct mbuf *opt, struct route *ro, int flags,
270     struct ip_moptions *imo, struct inpcb *inp)
271 {
272 	struct rm_priotracker in_ifa_tracker;
273 	struct epoch_tracker et;
274 	struct ip *ip;
275 	struct ifnet *ifp = NULL;	/* keep compiler happy */
276 	struct mbuf *m0;
277 	int hlen = sizeof (struct ip);
278 	int mtu;
279 	int error = 0;
280 	struct sockaddr_in *dst, sin;
281 	const struct sockaddr_in *gw;
282 	struct in_ifaddr *ia;
283 	struct in_addr src;
284 	int isbroadcast;
285 	uint16_t ip_len, ip_off;
286 	uint32_t fibnum;
287 #if defined(IPSEC) || defined(IPSEC_SUPPORT)
288 	int no_route_but_check_spd = 0;
289 #endif
290 
291 	M_ASSERTPKTHDR(m);
292 
293 	if (inp != NULL) {
294 		INP_LOCK_ASSERT(inp);
295 		M_SETFIB(m, inp->inp_inc.inc_fibnum);
296 		if ((flags & IP_NODEFAULTFLOWID) == 0) {
297 			m->m_pkthdr.flowid = inp->inp_flowid;
298 			M_HASHTYPE_SET(m, inp->inp_flowtype);
299 		}
300 #ifdef NUMA
301 		m->m_pkthdr.numa_domain = inp->inp_numa_domain;
302 #endif
303 	}
304 
305 	if (opt) {
306 		int len = 0;
307 		m = ip_insertoptions(m, opt, &len);
308 		if (len != 0)
309 			hlen = len; /* ip->ip_hl is updated above */
310 	}
311 	ip = mtod(m, struct ip *);
312 	ip_len = ntohs(ip->ip_len);
313 	ip_off = ntohs(ip->ip_off);
314 
315 	if ((flags & (IP_FORWARDING|IP_RAWOUTPUT)) == 0) {
316 		ip->ip_v = IPVERSION;
317 		ip->ip_hl = hlen >> 2;
318 		ip_fillid(ip);
319 	} else {
320 		/* Header already set, fetch hlen from there */
321 		hlen = ip->ip_hl << 2;
322 	}
323 	if ((flags & IP_FORWARDING) == 0)
324 		IPSTAT_INC(ips_localout);
325 
326 	/*
327 	 * dst/gw handling:
328 	 *
329 	 * gw is readonly but can point either to dst OR rt_gateway,
330 	 * therefore we need restore gw if we're redoing lookup.
331 	 */
332 	fibnum = (inp != NULL) ? inp->inp_inc.inc_fibnum : M_GETFIB(m);
333 	if (ro != NULL)
334 		dst = (struct sockaddr_in *)&ro->ro_dst;
335 	else
336 		dst = &sin;
337 	if (ro == NULL || ro->ro_rt == NULL) {
338 		bzero(dst, sizeof(*dst));
339 		dst->sin_family = AF_INET;
340 		dst->sin_len = sizeof(*dst);
341 		dst->sin_addr = ip->ip_dst;
342 	}
343 	gw = dst;
344 	NET_EPOCH_ENTER(et);
345 again:
346 	/*
347 	 * Validate route against routing table additions;
348 	 * a better/more specific route might have been added.
349 	 */
350 	if (inp != NULL && ro != NULL && ro->ro_rt != NULL)
351 		RT_VALIDATE(ro, &inp->inp_rt_cookie, fibnum);
352 	/*
353 	 * If there is a cached route,
354 	 * check that it is to the same destination
355 	 * and is still up.  If not, free it and try again.
356 	 * The address family should also be checked in case of sharing the
357 	 * cache with IPv6.
358 	 * Also check whether routing cache needs invalidation.
359 	 */
360 	if (ro != NULL && ro->ro_rt != NULL &&
361 	    ((ro->ro_rt->rt_flags & RTF_UP) == 0 ||
362 	    ro->ro_rt->rt_ifp == NULL || !RT_LINK_IS_UP(ro->ro_rt->rt_ifp) ||
363 	    dst->sin_family != AF_INET ||
364 	    dst->sin_addr.s_addr != ip->ip_dst.s_addr))
365 		RO_INVALIDATE_CACHE(ro);
366 	ia = NULL;
367 	/*
368 	 * If routing to interface only, short circuit routing lookup.
369 	 * The use of an all-ones broadcast address implies this; an
370 	 * interface is specified by the broadcast address of an interface,
371 	 * or the destination address of a ptp interface.
372 	 */
373 	if (flags & IP_SENDONES) {
374 		if ((ia = ifatoia(ifa_ifwithbroadaddr(sintosa(dst),
375 						      M_GETFIB(m)))) == NULL &&
376 		    (ia = ifatoia(ifa_ifwithdstaddr(sintosa(dst),
377 						    M_GETFIB(m)))) == NULL) {
378 			IPSTAT_INC(ips_noroute);
379 			error = ENETUNREACH;
380 			goto bad;
381 		}
382 		ip->ip_dst.s_addr = INADDR_BROADCAST;
383 		dst->sin_addr = ip->ip_dst;
384 		ifp = ia->ia_ifp;
385 		mtu = ifp->if_mtu;
386 		ip->ip_ttl = 1;
387 		isbroadcast = 1;
388 		src = IA_SIN(ia)->sin_addr;
389 	} else if (flags & IP_ROUTETOIF) {
390 		if ((ia = ifatoia(ifa_ifwithdstaddr(sintosa(dst),
391 						    M_GETFIB(m)))) == NULL &&
392 		    (ia = ifatoia(ifa_ifwithnet(sintosa(dst), 0,
393 						M_GETFIB(m)))) == NULL) {
394 			IPSTAT_INC(ips_noroute);
395 			error = ENETUNREACH;
396 			goto bad;
397 		}
398 		ifp = ia->ia_ifp;
399 		mtu = ifp->if_mtu;
400 		ip->ip_ttl = 1;
401 		isbroadcast = ifp->if_flags & IFF_BROADCAST ?
402 		    in_ifaddr_broadcast(dst->sin_addr, ia) : 0;
403 		src = IA_SIN(ia)->sin_addr;
404 	} else if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr)) &&
405 	    imo != NULL && imo->imo_multicast_ifp != NULL) {
406 		/*
407 		 * Bypass the normal routing lookup for multicast
408 		 * packets if the interface is specified.
409 		 */
410 		ifp = imo->imo_multicast_ifp;
411 		mtu = ifp->if_mtu;
412 		IFP_TO_IA(ifp, ia, &in_ifa_tracker);
413 		isbroadcast = 0;	/* fool gcc */
414 		/* Interface may have no addresses. */
415 		if (ia != NULL)
416 			src = IA_SIN(ia)->sin_addr;
417 		else
418 			src.s_addr = INADDR_ANY;
419 	} else if (ro != NULL) {
420 		if (ro->ro_rt == NULL) {
421 			/*
422 			 * We want to do any cloning requested by the link
423 			 * layer, as this is probably required in all cases
424 			 * for correct operation (as it is for ARP).
425 			 */
426 #ifdef RADIX_MPATH
427 			rtalloc_mpath_fib(ro,
428 			    ntohl(ip->ip_src.s_addr ^ ip->ip_dst.s_addr),
429 			    fibnum);
430 #else
431 			in_rtalloc_ign(ro, 0, fibnum);
432 #endif
433 			if (ro->ro_rt == NULL ||
434 			    (ro->ro_rt->rt_flags & RTF_UP) == 0 ||
435 			    ro->ro_rt->rt_ifp == NULL ||
436 			    !RT_LINK_IS_UP(ro->ro_rt->rt_ifp)) {
437 #if defined(IPSEC) || defined(IPSEC_SUPPORT)
438 				/*
439 				 * There is no route for this packet, but it is
440 				 * possible that a matching SPD entry exists.
441 				 */
442 				no_route_but_check_spd = 1;
443 				mtu = 0; /* Silence GCC warning. */
444 				goto sendit;
445 #endif
446 				IPSTAT_INC(ips_noroute);
447 				error = EHOSTUNREACH;
448 				goto bad;
449 			}
450 		}
451 		ia = ifatoia(ro->ro_rt->rt_ifa);
452 		ifp = ro->ro_rt->rt_ifp;
453 		counter_u64_add(ro->ro_rt->rt_pksent, 1);
454 		rt_update_ro_flags(ro);
455 		if (ro->ro_rt->rt_flags & RTF_GATEWAY)
456 			gw = (struct sockaddr_in *)ro->ro_rt->rt_gateway;
457 		if (ro->ro_rt->rt_flags & RTF_HOST)
458 			isbroadcast = (ro->ro_rt->rt_flags & RTF_BROADCAST);
459 		else if (ifp->if_flags & IFF_BROADCAST)
460 			isbroadcast = in_ifaddr_broadcast(gw->sin_addr, ia);
461 		else
462 			isbroadcast = 0;
463 		if (ro->ro_rt->rt_flags & RTF_HOST)
464 			mtu = ro->ro_rt->rt_mtu;
465 		else
466 			mtu = ifp->if_mtu;
467 		src = IA_SIN(ia)->sin_addr;
468 	} else {
469 		struct nhop4_extended nh;
470 
471 		bzero(&nh, sizeof(nh));
472 		if (fib4_lookup_nh_ext(M_GETFIB(m), ip->ip_dst, 0, 0, &nh) !=
473 		    0) {
474 #if defined(IPSEC) || defined(IPSEC_SUPPORT)
475 			/*
476 			 * There is no route for this packet, but it is
477 			 * possible that a matching SPD entry exists.
478 			 */
479 			no_route_but_check_spd = 1;
480 			mtu = 0; /* Silence GCC warning. */
481 			goto sendit;
482 #endif
483 			IPSTAT_INC(ips_noroute);
484 			error = EHOSTUNREACH;
485 			goto bad;
486 		}
487 		ifp = nh.nh_ifp;
488 		mtu = nh.nh_mtu;
489 		/*
490 		 * We are rewriting here dst to be gw actually, contradicting
491 		 * comment at the beginning of the function. However, in this
492 		 * case we are always dealing with on stack dst.
493 		 * In case if pfil(9) sends us back to beginning of the
494 		 * function, the dst would be rewritten by ip_output_pfil().
495 		 */
496 		MPASS(dst == &sin);
497 		dst->sin_addr = nh.nh_addr;
498 		ia = nh.nh_ia;
499 		src = nh.nh_src;
500 		isbroadcast = (((nh.nh_flags & (NHF_HOST | NHF_BROADCAST)) ==
501 		    (NHF_HOST | NHF_BROADCAST)) ||
502 		    ((ifp->if_flags & IFF_BROADCAST) &&
503 		    in_ifaddr_broadcast(dst->sin_addr, ia)));
504 	}
505 
506 	/* Catch a possible divide by zero later. */
507 	KASSERT(mtu > 0, ("%s: mtu %d <= 0, ro=%p (rt_flags=0x%08x) ifp=%p",
508 	    __func__, mtu, ro,
509 	    (ro != NULL && ro->ro_rt != NULL) ? ro->ro_rt->rt_flags : 0, ifp));
510 
511 	if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) {
512 		m->m_flags |= M_MCAST;
513 		/*
514 		 * IP destination address is multicast.  Make sure "gw"
515 		 * still points to the address in "ro".  (It may have been
516 		 * changed to point to a gateway address, above.)
517 		 */
518 		gw = dst;
519 		/*
520 		 * See if the caller provided any multicast options
521 		 */
522 		if (imo != NULL) {
523 			ip->ip_ttl = imo->imo_multicast_ttl;
524 			if (imo->imo_multicast_vif != -1)
525 				ip->ip_src.s_addr =
526 				    ip_mcast_src ?
527 				    ip_mcast_src(imo->imo_multicast_vif) :
528 				    INADDR_ANY;
529 		} else
530 			ip->ip_ttl = IP_DEFAULT_MULTICAST_TTL;
531 		/*
532 		 * Confirm that the outgoing interface supports multicast.
533 		 */
534 		if ((imo == NULL) || (imo->imo_multicast_vif == -1)) {
535 			if ((ifp->if_flags & IFF_MULTICAST) == 0) {
536 				IPSTAT_INC(ips_noroute);
537 				error = ENETUNREACH;
538 				goto bad;
539 			}
540 		}
541 		/*
542 		 * If source address not specified yet, use address
543 		 * of outgoing interface.
544 		 */
545 		if (ip->ip_src.s_addr == INADDR_ANY)
546 			ip->ip_src = src;
547 
548 		if ((imo == NULL && in_mcast_loop) ||
549 		    (imo && imo->imo_multicast_loop)) {
550 			/*
551 			 * Loop back multicast datagram if not expressly
552 			 * forbidden to do so, even if we are not a member
553 			 * of the group; ip_input() will filter it later,
554 			 * thus deferring a hash lookup and mutex acquisition
555 			 * at the expense of a cheap copy using m_copym().
556 			 */
557 			ip_mloopback(ifp, m, hlen);
558 		} else {
559 			/*
560 			 * If we are acting as a multicast router, perform
561 			 * multicast forwarding as if the packet had just
562 			 * arrived on the interface to which we are about
563 			 * to send.  The multicast forwarding function
564 			 * recursively calls this function, using the
565 			 * IP_FORWARDING flag to prevent infinite recursion.
566 			 *
567 			 * Multicasts that are looped back by ip_mloopback(),
568 			 * above, will be forwarded by the ip_input() routine,
569 			 * if necessary.
570 			 */
571 			if (V_ip_mrouter && (flags & IP_FORWARDING) == 0) {
572 				/*
573 				 * If rsvp daemon is not running, do not
574 				 * set ip_moptions. This ensures that the packet
575 				 * is multicast and not just sent down one link
576 				 * as prescribed by rsvpd.
577 				 */
578 				if (!V_rsvp_on)
579 					imo = NULL;
580 				if (ip_mforward &&
581 				    ip_mforward(ip, ifp, m, imo) != 0) {
582 					m_freem(m);
583 					goto done;
584 				}
585 			}
586 		}
587 
588 		/*
589 		 * Multicasts with a time-to-live of zero may be looped-
590 		 * back, above, but must not be transmitted on a network.
591 		 * Also, multicasts addressed to the loopback interface
592 		 * are not sent -- the above call to ip_mloopback() will
593 		 * loop back a copy. ip_input() will drop the copy if
594 		 * this host does not belong to the destination group on
595 		 * the loopback interface.
596 		 */
597 		if (ip->ip_ttl == 0 || ifp->if_flags & IFF_LOOPBACK) {
598 			m_freem(m);
599 			goto done;
600 		}
601 
602 		goto sendit;
603 	}
604 
605 	/*
606 	 * If the source address is not specified yet, use the address
607 	 * of the outoing interface.
608 	 */
609 	if (ip->ip_src.s_addr == INADDR_ANY)
610 		ip->ip_src = src;
611 
612 	/*
613 	 * Look for broadcast address and
614 	 * verify user is allowed to send
615 	 * such a packet.
616 	 */
617 	if (isbroadcast) {
618 		if ((ifp->if_flags & IFF_BROADCAST) == 0) {
619 			error = EADDRNOTAVAIL;
620 			goto bad;
621 		}
622 		if ((flags & IP_ALLOWBROADCAST) == 0) {
623 			error = EACCES;
624 			goto bad;
625 		}
626 		/* don't allow broadcast messages to be fragmented */
627 		if (ip_len > mtu) {
628 			error = EMSGSIZE;
629 			goto bad;
630 		}
631 		m->m_flags |= M_BCAST;
632 	} else {
633 		m->m_flags &= ~M_BCAST;
634 	}
635 
636 sendit:
637 #if defined(IPSEC) || defined(IPSEC_SUPPORT)
638 	if (IPSEC_ENABLED(ipv4)) {
639 		if ((error = IPSEC_OUTPUT(ipv4, m, inp)) != 0) {
640 			if (error == EINPROGRESS)
641 				error = 0;
642 			goto done;
643 		}
644 	}
645 	/*
646 	 * Check if there was a route for this packet; return error if not.
647 	 */
648 	if (no_route_but_check_spd) {
649 		IPSTAT_INC(ips_noroute);
650 		error = EHOSTUNREACH;
651 		goto bad;
652 	}
653 	/* Update variables that are affected by ipsec4_output(). */
654 	ip = mtod(m, struct ip *);
655 	hlen = ip->ip_hl << 2;
656 #endif /* IPSEC */
657 
658 	/* Jump over all PFIL processing if hooks are not active. */
659 	if (PFIL_HOOKED_OUT(V_inet_pfil_head)) {
660 		switch (ip_output_pfil(&m, ifp, flags, inp, dst, &fibnum,
661 		    &error)) {
662 		case 1: /* Finished */
663 			goto done;
664 
665 		case 0: /* Continue normally */
666 			ip = mtod(m, struct ip *);
667 			break;
668 
669 		case -1: /* Need to try again */
670 			/* Reset everything for a new round */
671 			if (ro != NULL) {
672 				RO_RTFREE(ro);
673 				ro->ro_prepend = NULL;
674 			}
675 			gw = dst;
676 			ip = mtod(m, struct ip *);
677 			goto again;
678 
679 		}
680 	}
681 
682 	/* IN_LOOPBACK must not appear on the wire - RFC1122. */
683 	if (IN_LOOPBACK(ntohl(ip->ip_dst.s_addr)) ||
684 	    IN_LOOPBACK(ntohl(ip->ip_src.s_addr))) {
685 		if ((ifp->if_flags & IFF_LOOPBACK) == 0) {
686 			IPSTAT_INC(ips_badaddr);
687 			error = EADDRNOTAVAIL;
688 			goto bad;
689 		}
690 	}
691 
692 	m->m_pkthdr.csum_flags |= CSUM_IP;
693 	if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA & ~ifp->if_hwassist) {
694 		m = mb_unmapped_to_ext(m);
695 		if (m == NULL) {
696 			IPSTAT_INC(ips_odropped);
697 			error = ENOBUFS;
698 			goto bad;
699 		}
700 		in_delayed_cksum(m);
701 		m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
702 	} else if ((ifp->if_capenable & IFCAP_NOMAP) == 0) {
703 		m = mb_unmapped_to_ext(m);
704 		if (m == NULL) {
705 			IPSTAT_INC(ips_odropped);
706 			error = ENOBUFS;
707 			goto bad;
708 		}
709 	}
710 #ifdef SCTP
711 	if (m->m_pkthdr.csum_flags & CSUM_SCTP & ~ifp->if_hwassist) {
712 		m = mb_unmapped_to_ext(m);
713 		if (m == NULL) {
714 			IPSTAT_INC(ips_odropped);
715 			error = ENOBUFS;
716 			goto bad;
717 		}
718 		sctp_delayed_cksum(m, (uint32_t)(ip->ip_hl << 2));
719 		m->m_pkthdr.csum_flags &= ~CSUM_SCTP;
720 	}
721 #endif
722 
723 	/*
724 	 * If small enough for interface, or the interface will take
725 	 * care of the fragmentation for us, we can just send directly.
726 	 */
727 	if (ip_len <= mtu ||
728 	    (m->m_pkthdr.csum_flags & ifp->if_hwassist & CSUM_TSO) != 0) {
729 		ip->ip_sum = 0;
730 		if (m->m_pkthdr.csum_flags & CSUM_IP & ~ifp->if_hwassist) {
731 			ip->ip_sum = in_cksum(m, hlen);
732 			m->m_pkthdr.csum_flags &= ~CSUM_IP;
733 		}
734 
735 		/*
736 		 * Record statistics for this interface address.
737 		 * With CSUM_TSO the byte/packet count will be slightly
738 		 * incorrect because we count the IP+TCP headers only
739 		 * once instead of for every generated packet.
740 		 */
741 		if (!(flags & IP_FORWARDING) && ia) {
742 			if (m->m_pkthdr.csum_flags & CSUM_TSO)
743 				counter_u64_add(ia->ia_ifa.ifa_opackets,
744 				    m->m_pkthdr.len / m->m_pkthdr.tso_segsz);
745 			else
746 				counter_u64_add(ia->ia_ifa.ifa_opackets, 1);
747 
748 			counter_u64_add(ia->ia_ifa.ifa_obytes, m->m_pkthdr.len);
749 		}
750 #ifdef MBUF_STRESS_TEST
751 		if (mbuf_frag_size && m->m_pkthdr.len > mbuf_frag_size)
752 			m = m_fragment(m, M_NOWAIT, mbuf_frag_size);
753 #endif
754 		/*
755 		 * Reset layer specific mbuf flags
756 		 * to avoid confusing lower layers.
757 		 */
758 		m_clrprotoflags(m);
759 		IP_PROBE(send, NULL, NULL, ip, ifp, ip, NULL);
760 		error = ip_output_send(inp, ifp, m, gw, ro);
761 		goto done;
762 	}
763 
764 	/* Balk when DF bit is set or the interface didn't support TSO. */
765 	if ((ip_off & IP_DF) || (m->m_pkthdr.csum_flags & CSUM_TSO)) {
766 		error = EMSGSIZE;
767 		IPSTAT_INC(ips_cantfrag);
768 		goto bad;
769 	}
770 
771 	/*
772 	 * Too large for interface; fragment if possible. If successful,
773 	 * on return, m will point to a list of packets to be sent.
774 	 */
775 	error = ip_fragment(ip, &m, mtu, ifp->if_hwassist);
776 	if (error)
777 		goto bad;
778 	for (; m; m = m0) {
779 		m0 = m->m_nextpkt;
780 		m->m_nextpkt = 0;
781 		if (error == 0) {
782 			/* Record statistics for this interface address. */
783 			if (ia != NULL) {
784 				counter_u64_add(ia->ia_ifa.ifa_opackets, 1);
785 				counter_u64_add(ia->ia_ifa.ifa_obytes,
786 				    m->m_pkthdr.len);
787 			}
788 			/*
789 			 * Reset layer specific mbuf flags
790 			 * to avoid confusing upper layers.
791 			 */
792 			m_clrprotoflags(m);
793 
794 			IP_PROBE(send, NULL, NULL, mtod(m, struct ip *), ifp,
795 			    mtod(m, struct ip *), NULL);
796 			error = ip_output_send(inp, ifp, m, gw, ro);
797 		} else
798 			m_freem(m);
799 	}
800 
801 	if (error == 0)
802 		IPSTAT_INC(ips_fragmented);
803 
804 done:
805 	NET_EPOCH_EXIT(et);
806 	return (error);
807  bad:
808 	m_freem(m);
809 	goto done;
810 }
811 
812 /*
813  * Create a chain of fragments which fit the given mtu. m_frag points to the
814  * mbuf to be fragmented; on return it points to the chain with the fragments.
815  * Return 0 if no error. If error, m_frag may contain a partially built
816  * chain of fragments that should be freed by the caller.
817  *
818  * if_hwassist_flags is the hw offload capabilities (see if_data.ifi_hwassist)
819  */
820 int
821 ip_fragment(struct ip *ip, struct mbuf **m_frag, int mtu,
822     u_long if_hwassist_flags)
823 {
824 	int error = 0;
825 	int hlen = ip->ip_hl << 2;
826 	int len = (mtu - hlen) & ~7;	/* size of payload in each fragment */
827 	int off;
828 	struct mbuf *m0 = *m_frag;	/* the original packet		*/
829 	int firstlen;
830 	struct mbuf **mnext;
831 	int nfrags;
832 	uint16_t ip_len, ip_off;
833 
834 	ip_len = ntohs(ip->ip_len);
835 	ip_off = ntohs(ip->ip_off);
836 
837 	if (ip_off & IP_DF) {	/* Fragmentation not allowed */
838 		IPSTAT_INC(ips_cantfrag);
839 		return EMSGSIZE;
840 	}
841 
842 	/*
843 	 * Must be able to put at least 8 bytes per fragment.
844 	 */
845 	if (len < 8)
846 		return EMSGSIZE;
847 
848 	/*
849 	 * If the interface will not calculate checksums on
850 	 * fragmented packets, then do it here.
851 	 */
852 	if (m0->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
853 		m0 = mb_unmapped_to_ext(m0);
854 		if (m0 == NULL) {
855 			error = ENOBUFS;
856 			IPSTAT_INC(ips_odropped);
857 			goto done;
858 		}
859 		in_delayed_cksum(m0);
860 		m0->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
861 	}
862 #ifdef SCTP
863 	if (m0->m_pkthdr.csum_flags & CSUM_SCTP) {
864 		m0 = mb_unmapped_to_ext(m0);
865 		if (m0 == NULL) {
866 			error = ENOBUFS;
867 			IPSTAT_INC(ips_odropped);
868 			goto done;
869 		}
870 		sctp_delayed_cksum(m0, hlen);
871 		m0->m_pkthdr.csum_flags &= ~CSUM_SCTP;
872 	}
873 #endif
874 	if (len > PAGE_SIZE) {
875 		/*
876 		 * Fragment large datagrams such that each segment
877 		 * contains a multiple of PAGE_SIZE amount of data,
878 		 * plus headers. This enables a receiver to perform
879 		 * page-flipping zero-copy optimizations.
880 		 *
881 		 * XXX When does this help given that sender and receiver
882 		 * could have different page sizes, and also mtu could
883 		 * be less than the receiver's page size ?
884 		 */
885 		int newlen;
886 
887 		off = MIN(mtu, m0->m_pkthdr.len);
888 
889 		/*
890 		 * firstlen (off - hlen) must be aligned on an
891 		 * 8-byte boundary
892 		 */
893 		if (off < hlen)
894 			goto smart_frag_failure;
895 		off = ((off - hlen) & ~7) + hlen;
896 		newlen = (~PAGE_MASK) & mtu;
897 		if ((newlen + sizeof (struct ip)) > mtu) {
898 			/* we failed, go back the default */
899 smart_frag_failure:
900 			newlen = len;
901 			off = hlen + len;
902 		}
903 		len = newlen;
904 
905 	} else {
906 		off = hlen + len;
907 	}
908 
909 	firstlen = off - hlen;
910 	mnext = &m0->m_nextpkt;		/* pointer to next packet */
911 
912 	/*
913 	 * Loop through length of segment after first fragment,
914 	 * make new header and copy data of each part and link onto chain.
915 	 * Here, m0 is the original packet, m is the fragment being created.
916 	 * The fragments are linked off the m_nextpkt of the original
917 	 * packet, which after processing serves as the first fragment.
918 	 */
919 	for (nfrags = 1; off < ip_len; off += len, nfrags++) {
920 		struct ip *mhip;	/* ip header on the fragment */
921 		struct mbuf *m;
922 		int mhlen = sizeof (struct ip);
923 
924 		m = m_gethdr(M_NOWAIT, MT_DATA);
925 		if (m == NULL) {
926 			error = ENOBUFS;
927 			IPSTAT_INC(ips_odropped);
928 			goto done;
929 		}
930 		/*
931 		 * Make sure the complete packet header gets copied
932 		 * from the originating mbuf to the newly created
933 		 * mbuf. This also ensures that existing firewall
934 		 * classification(s), VLAN tags and so on get copied
935 		 * to the resulting fragmented packet(s):
936 		 */
937 		if (m_dup_pkthdr(m, m0, M_NOWAIT) == 0) {
938 			m_free(m);
939 			error = ENOBUFS;
940 			IPSTAT_INC(ips_odropped);
941 			goto done;
942 		}
943 		/*
944 		 * In the first mbuf, leave room for the link header, then
945 		 * copy the original IP header including options. The payload
946 		 * goes into an additional mbuf chain returned by m_copym().
947 		 */
948 		m->m_data += max_linkhdr;
949 		mhip = mtod(m, struct ip *);
950 		*mhip = *ip;
951 		if (hlen > sizeof (struct ip)) {
952 			mhlen = ip_optcopy(ip, mhip) + sizeof (struct ip);
953 			mhip->ip_v = IPVERSION;
954 			mhip->ip_hl = mhlen >> 2;
955 		}
956 		m->m_len = mhlen;
957 		/* XXX do we need to add ip_off below ? */
958 		mhip->ip_off = ((off - hlen) >> 3) + ip_off;
959 		if (off + len >= ip_len)
960 			len = ip_len - off;
961 		else
962 			mhip->ip_off |= IP_MF;
963 		mhip->ip_len = htons((u_short)(len + mhlen));
964 		m->m_next = m_copym(m0, off, len, M_NOWAIT);
965 		if (m->m_next == NULL) {	/* copy failed */
966 			m_free(m);
967 			error = ENOBUFS;	/* ??? */
968 			IPSTAT_INC(ips_odropped);
969 			goto done;
970 		}
971 		m->m_pkthdr.len = mhlen + len;
972 #ifdef MAC
973 		mac_netinet_fragment(m0, m);
974 #endif
975 		mhip->ip_off = htons(mhip->ip_off);
976 		mhip->ip_sum = 0;
977 		if (m->m_pkthdr.csum_flags & CSUM_IP & ~if_hwassist_flags) {
978 			mhip->ip_sum = in_cksum(m, mhlen);
979 			m->m_pkthdr.csum_flags &= ~CSUM_IP;
980 		}
981 		*mnext = m;
982 		mnext = &m->m_nextpkt;
983 	}
984 	IPSTAT_ADD(ips_ofragments, nfrags);
985 
986 	/*
987 	 * Update first fragment by trimming what's been copied out
988 	 * and updating header.
989 	 */
990 	m_adj(m0, hlen + firstlen - ip_len);
991 	m0->m_pkthdr.len = hlen + firstlen;
992 	ip->ip_len = htons((u_short)m0->m_pkthdr.len);
993 	ip->ip_off = htons(ip_off | IP_MF);
994 	ip->ip_sum = 0;
995 	if (m0->m_pkthdr.csum_flags & CSUM_IP & ~if_hwassist_flags) {
996 		ip->ip_sum = in_cksum(m0, hlen);
997 		m0->m_pkthdr.csum_flags &= ~CSUM_IP;
998 	}
999 
1000 done:
1001 	*m_frag = m0;
1002 	return error;
1003 }
1004 
1005 void
1006 in_delayed_cksum(struct mbuf *m)
1007 {
1008 	struct ip *ip;
1009 	struct udphdr *uh;
1010 	uint16_t cklen, csum, offset;
1011 
1012 	ip = mtod(m, struct ip *);
1013 	offset = ip->ip_hl << 2 ;
1014 
1015 	if (m->m_pkthdr.csum_flags & CSUM_UDP) {
1016 		/* if udp header is not in the first mbuf copy udplen */
1017 		if (offset + sizeof(struct udphdr) > m->m_len) {
1018 			m_copydata(m, offset + offsetof(struct udphdr,
1019 			    uh_ulen), sizeof(cklen), (caddr_t)&cklen);
1020 			cklen = ntohs(cklen);
1021 		} else {
1022 			uh = (struct udphdr *)mtodo(m, offset);
1023 			cklen = ntohs(uh->uh_ulen);
1024 		}
1025 		csum = in_cksum_skip(m, cklen + offset, offset);
1026 		if (csum == 0)
1027 			csum = 0xffff;
1028 	} else {
1029 		cklen = ntohs(ip->ip_len);
1030 		csum = in_cksum_skip(m, cklen, offset);
1031 	}
1032 	offset += m->m_pkthdr.csum_data;	/* checksum offset */
1033 
1034 	if (offset + sizeof(csum) > m->m_len)
1035 		m_copyback(m, offset, sizeof(csum), (caddr_t)&csum);
1036 	else
1037 		*(u_short *)mtodo(m, offset) = csum;
1038 }
1039 
1040 /*
1041  * IP socket option processing.
1042  */
1043 int
1044 ip_ctloutput(struct socket *so, struct sockopt *sopt)
1045 {
1046 	struct	inpcb *inp = sotoinpcb(so);
1047 	int	error, optval;
1048 #ifdef	RSS
1049 	uint32_t rss_bucket;
1050 	int retval;
1051 #endif
1052 
1053 	error = optval = 0;
1054 	if (sopt->sopt_level != IPPROTO_IP) {
1055 		error = EINVAL;
1056 
1057 		if (sopt->sopt_level == SOL_SOCKET &&
1058 		    sopt->sopt_dir == SOPT_SET) {
1059 			switch (sopt->sopt_name) {
1060 			case SO_REUSEADDR:
1061 				INP_WLOCK(inp);
1062 				if ((so->so_options & SO_REUSEADDR) != 0)
1063 					inp->inp_flags2 |= INP_REUSEADDR;
1064 				else
1065 					inp->inp_flags2 &= ~INP_REUSEADDR;
1066 				INP_WUNLOCK(inp);
1067 				error = 0;
1068 				break;
1069 			case SO_REUSEPORT:
1070 				INP_WLOCK(inp);
1071 				if ((so->so_options & SO_REUSEPORT) != 0)
1072 					inp->inp_flags2 |= INP_REUSEPORT;
1073 				else
1074 					inp->inp_flags2 &= ~INP_REUSEPORT;
1075 				INP_WUNLOCK(inp);
1076 				error = 0;
1077 				break;
1078 			case SO_REUSEPORT_LB:
1079 				INP_WLOCK(inp);
1080 				if ((so->so_options & SO_REUSEPORT_LB) != 0)
1081 					inp->inp_flags2 |= INP_REUSEPORT_LB;
1082 				else
1083 					inp->inp_flags2 &= ~INP_REUSEPORT_LB;
1084 				INP_WUNLOCK(inp);
1085 				error = 0;
1086 				break;
1087 			case SO_SETFIB:
1088 				INP_WLOCK(inp);
1089 				inp->inp_inc.inc_fibnum = so->so_fibnum;
1090 				INP_WUNLOCK(inp);
1091 				error = 0;
1092 				break;
1093 			case SO_MAX_PACING_RATE:
1094 #ifdef RATELIMIT
1095 				INP_WLOCK(inp);
1096 				inp->inp_flags2 |= INP_RATE_LIMIT_CHANGED;
1097 				INP_WUNLOCK(inp);
1098 				error = 0;
1099 #else
1100 				error = EOPNOTSUPP;
1101 #endif
1102 				break;
1103 			default:
1104 				break;
1105 			}
1106 		}
1107 		return (error);
1108 	}
1109 
1110 	switch (sopt->sopt_dir) {
1111 	case SOPT_SET:
1112 		switch (sopt->sopt_name) {
1113 		case IP_OPTIONS:
1114 #ifdef notyet
1115 		case IP_RETOPTS:
1116 #endif
1117 		{
1118 			struct mbuf *m;
1119 			if (sopt->sopt_valsize > MLEN) {
1120 				error = EMSGSIZE;
1121 				break;
1122 			}
1123 			m = m_get(sopt->sopt_td ? M_WAITOK : M_NOWAIT, MT_DATA);
1124 			if (m == NULL) {
1125 				error = ENOBUFS;
1126 				break;
1127 			}
1128 			m->m_len = sopt->sopt_valsize;
1129 			error = sooptcopyin(sopt, mtod(m, char *), m->m_len,
1130 					    m->m_len);
1131 			if (error) {
1132 				m_free(m);
1133 				break;
1134 			}
1135 			INP_WLOCK(inp);
1136 			error = ip_pcbopts(inp, sopt->sopt_name, m);
1137 			INP_WUNLOCK(inp);
1138 			return (error);
1139 		}
1140 
1141 		case IP_BINDANY:
1142 			if (sopt->sopt_td != NULL) {
1143 				error = priv_check(sopt->sopt_td,
1144 				    PRIV_NETINET_BINDANY);
1145 				if (error)
1146 					break;
1147 			}
1148 			/* FALLTHROUGH */
1149 		case IP_BINDMULTI:
1150 #ifdef	RSS
1151 		case IP_RSS_LISTEN_BUCKET:
1152 #endif
1153 		case IP_TOS:
1154 		case IP_TTL:
1155 		case IP_MINTTL:
1156 		case IP_RECVOPTS:
1157 		case IP_RECVRETOPTS:
1158 		case IP_ORIGDSTADDR:
1159 		case IP_RECVDSTADDR:
1160 		case IP_RECVTTL:
1161 		case IP_RECVIF:
1162 		case IP_ONESBCAST:
1163 		case IP_DONTFRAG:
1164 		case IP_RECVTOS:
1165 		case IP_RECVFLOWID:
1166 #ifdef	RSS
1167 		case IP_RECVRSSBUCKETID:
1168 #endif
1169 			error = sooptcopyin(sopt, &optval, sizeof optval,
1170 					    sizeof optval);
1171 			if (error)
1172 				break;
1173 
1174 			switch (sopt->sopt_name) {
1175 			case IP_TOS:
1176 				inp->inp_ip_tos = optval;
1177 				break;
1178 
1179 			case IP_TTL:
1180 				inp->inp_ip_ttl = optval;
1181 				break;
1182 
1183 			case IP_MINTTL:
1184 				if (optval >= 0 && optval <= MAXTTL)
1185 					inp->inp_ip_minttl = optval;
1186 				else
1187 					error = EINVAL;
1188 				break;
1189 
1190 #define	OPTSET(bit) do {						\
1191 	INP_WLOCK(inp);							\
1192 	if (optval)							\
1193 		inp->inp_flags |= bit;					\
1194 	else								\
1195 		inp->inp_flags &= ~bit;					\
1196 	INP_WUNLOCK(inp);						\
1197 } while (0)
1198 
1199 #define	OPTSET2(bit, val) do {						\
1200 	INP_WLOCK(inp);							\
1201 	if (val)							\
1202 		inp->inp_flags2 |= bit;					\
1203 	else								\
1204 		inp->inp_flags2 &= ~bit;				\
1205 	INP_WUNLOCK(inp);						\
1206 } while (0)
1207 
1208 			case IP_RECVOPTS:
1209 				OPTSET(INP_RECVOPTS);
1210 				break;
1211 
1212 			case IP_RECVRETOPTS:
1213 				OPTSET(INP_RECVRETOPTS);
1214 				break;
1215 
1216 			case IP_RECVDSTADDR:
1217 				OPTSET(INP_RECVDSTADDR);
1218 				break;
1219 
1220 			case IP_ORIGDSTADDR:
1221 				OPTSET2(INP_ORIGDSTADDR, optval);
1222 				break;
1223 
1224 			case IP_RECVTTL:
1225 				OPTSET(INP_RECVTTL);
1226 				break;
1227 
1228 			case IP_RECVIF:
1229 				OPTSET(INP_RECVIF);
1230 				break;
1231 
1232 			case IP_ONESBCAST:
1233 				OPTSET(INP_ONESBCAST);
1234 				break;
1235 			case IP_DONTFRAG:
1236 				OPTSET(INP_DONTFRAG);
1237 				break;
1238 			case IP_BINDANY:
1239 				OPTSET(INP_BINDANY);
1240 				break;
1241 			case IP_RECVTOS:
1242 				OPTSET(INP_RECVTOS);
1243 				break;
1244 			case IP_BINDMULTI:
1245 				OPTSET2(INP_BINDMULTI, optval);
1246 				break;
1247 			case IP_RECVFLOWID:
1248 				OPTSET2(INP_RECVFLOWID, optval);
1249 				break;
1250 #ifdef	RSS
1251 			case IP_RSS_LISTEN_BUCKET:
1252 				if ((optval >= 0) &&
1253 				    (optval < rss_getnumbuckets())) {
1254 					inp->inp_rss_listen_bucket = optval;
1255 					OPTSET2(INP_RSS_BUCKET_SET, 1);
1256 				} else {
1257 					error = EINVAL;
1258 				}
1259 				break;
1260 			case IP_RECVRSSBUCKETID:
1261 				OPTSET2(INP_RECVRSSBUCKETID, optval);
1262 				break;
1263 #endif
1264 			}
1265 			break;
1266 #undef OPTSET
1267 #undef OPTSET2
1268 
1269 		/*
1270 		 * Multicast socket options are processed by the in_mcast
1271 		 * module.
1272 		 */
1273 		case IP_MULTICAST_IF:
1274 		case IP_MULTICAST_VIF:
1275 		case IP_MULTICAST_TTL:
1276 		case IP_MULTICAST_LOOP:
1277 		case IP_ADD_MEMBERSHIP:
1278 		case IP_DROP_MEMBERSHIP:
1279 		case IP_ADD_SOURCE_MEMBERSHIP:
1280 		case IP_DROP_SOURCE_MEMBERSHIP:
1281 		case IP_BLOCK_SOURCE:
1282 		case IP_UNBLOCK_SOURCE:
1283 		case IP_MSFILTER:
1284 		case MCAST_JOIN_GROUP:
1285 		case MCAST_LEAVE_GROUP:
1286 		case MCAST_JOIN_SOURCE_GROUP:
1287 		case MCAST_LEAVE_SOURCE_GROUP:
1288 		case MCAST_BLOCK_SOURCE:
1289 		case MCAST_UNBLOCK_SOURCE:
1290 			error = inp_setmoptions(inp, sopt);
1291 			break;
1292 
1293 		case IP_PORTRANGE:
1294 			error = sooptcopyin(sopt, &optval, sizeof optval,
1295 					    sizeof optval);
1296 			if (error)
1297 				break;
1298 
1299 			INP_WLOCK(inp);
1300 			switch (optval) {
1301 			case IP_PORTRANGE_DEFAULT:
1302 				inp->inp_flags &= ~(INP_LOWPORT);
1303 				inp->inp_flags &= ~(INP_HIGHPORT);
1304 				break;
1305 
1306 			case IP_PORTRANGE_HIGH:
1307 				inp->inp_flags &= ~(INP_LOWPORT);
1308 				inp->inp_flags |= INP_HIGHPORT;
1309 				break;
1310 
1311 			case IP_PORTRANGE_LOW:
1312 				inp->inp_flags &= ~(INP_HIGHPORT);
1313 				inp->inp_flags |= INP_LOWPORT;
1314 				break;
1315 
1316 			default:
1317 				error = EINVAL;
1318 				break;
1319 			}
1320 			INP_WUNLOCK(inp);
1321 			break;
1322 
1323 #if defined(IPSEC) || defined(IPSEC_SUPPORT)
1324 		case IP_IPSEC_POLICY:
1325 			if (IPSEC_ENABLED(ipv4)) {
1326 				error = IPSEC_PCBCTL(ipv4, inp, sopt);
1327 				break;
1328 			}
1329 			/* FALLTHROUGH */
1330 #endif /* IPSEC */
1331 
1332 		default:
1333 			error = ENOPROTOOPT;
1334 			break;
1335 		}
1336 		break;
1337 
1338 	case SOPT_GET:
1339 		switch (sopt->sopt_name) {
1340 		case IP_OPTIONS:
1341 		case IP_RETOPTS:
1342 			INP_RLOCK(inp);
1343 			if (inp->inp_options) {
1344 				struct mbuf *options;
1345 
1346 				options = m_copym(inp->inp_options, 0,
1347 				    M_COPYALL, M_NOWAIT);
1348 				INP_RUNLOCK(inp);
1349 				if (options != NULL) {
1350 					error = sooptcopyout(sopt,
1351 							     mtod(options, char *),
1352 							     options->m_len);
1353 					m_freem(options);
1354 				} else
1355 					error = ENOMEM;
1356 			} else {
1357 				INP_RUNLOCK(inp);
1358 				sopt->sopt_valsize = 0;
1359 			}
1360 			break;
1361 
1362 		case IP_TOS:
1363 		case IP_TTL:
1364 		case IP_MINTTL:
1365 		case IP_RECVOPTS:
1366 		case IP_RECVRETOPTS:
1367 		case IP_ORIGDSTADDR:
1368 		case IP_RECVDSTADDR:
1369 		case IP_RECVTTL:
1370 		case IP_RECVIF:
1371 		case IP_PORTRANGE:
1372 		case IP_ONESBCAST:
1373 		case IP_DONTFRAG:
1374 		case IP_BINDANY:
1375 		case IP_RECVTOS:
1376 		case IP_BINDMULTI:
1377 		case IP_FLOWID:
1378 		case IP_FLOWTYPE:
1379 		case IP_RECVFLOWID:
1380 #ifdef	RSS
1381 		case IP_RSSBUCKETID:
1382 		case IP_RECVRSSBUCKETID:
1383 #endif
1384 			switch (sopt->sopt_name) {
1385 
1386 			case IP_TOS:
1387 				optval = inp->inp_ip_tos;
1388 				break;
1389 
1390 			case IP_TTL:
1391 				optval = inp->inp_ip_ttl;
1392 				break;
1393 
1394 			case IP_MINTTL:
1395 				optval = inp->inp_ip_minttl;
1396 				break;
1397 
1398 #define	OPTBIT(bit)	(inp->inp_flags & bit ? 1 : 0)
1399 #define	OPTBIT2(bit)	(inp->inp_flags2 & bit ? 1 : 0)
1400 
1401 			case IP_RECVOPTS:
1402 				optval = OPTBIT(INP_RECVOPTS);
1403 				break;
1404 
1405 			case IP_RECVRETOPTS:
1406 				optval = OPTBIT(INP_RECVRETOPTS);
1407 				break;
1408 
1409 			case IP_RECVDSTADDR:
1410 				optval = OPTBIT(INP_RECVDSTADDR);
1411 				break;
1412 
1413 			case IP_ORIGDSTADDR:
1414 				optval = OPTBIT2(INP_ORIGDSTADDR);
1415 				break;
1416 
1417 			case IP_RECVTTL:
1418 				optval = OPTBIT(INP_RECVTTL);
1419 				break;
1420 
1421 			case IP_RECVIF:
1422 				optval = OPTBIT(INP_RECVIF);
1423 				break;
1424 
1425 			case IP_PORTRANGE:
1426 				if (inp->inp_flags & INP_HIGHPORT)
1427 					optval = IP_PORTRANGE_HIGH;
1428 				else if (inp->inp_flags & INP_LOWPORT)
1429 					optval = IP_PORTRANGE_LOW;
1430 				else
1431 					optval = 0;
1432 				break;
1433 
1434 			case IP_ONESBCAST:
1435 				optval = OPTBIT(INP_ONESBCAST);
1436 				break;
1437 			case IP_DONTFRAG:
1438 				optval = OPTBIT(INP_DONTFRAG);
1439 				break;
1440 			case IP_BINDANY:
1441 				optval = OPTBIT(INP_BINDANY);
1442 				break;
1443 			case IP_RECVTOS:
1444 				optval = OPTBIT(INP_RECVTOS);
1445 				break;
1446 			case IP_FLOWID:
1447 				optval = inp->inp_flowid;
1448 				break;
1449 			case IP_FLOWTYPE:
1450 				optval = inp->inp_flowtype;
1451 				break;
1452 			case IP_RECVFLOWID:
1453 				optval = OPTBIT2(INP_RECVFLOWID);
1454 				break;
1455 #ifdef	RSS
1456 			case IP_RSSBUCKETID:
1457 				retval = rss_hash2bucket(inp->inp_flowid,
1458 				    inp->inp_flowtype,
1459 				    &rss_bucket);
1460 				if (retval == 0)
1461 					optval = rss_bucket;
1462 				else
1463 					error = EINVAL;
1464 				break;
1465 			case IP_RECVRSSBUCKETID:
1466 				optval = OPTBIT2(INP_RECVRSSBUCKETID);
1467 				break;
1468 #endif
1469 			case IP_BINDMULTI:
1470 				optval = OPTBIT2(INP_BINDMULTI);
1471 				break;
1472 			}
1473 			error = sooptcopyout(sopt, &optval, sizeof optval);
1474 			break;
1475 
1476 		/*
1477 		 * Multicast socket options are processed by the in_mcast
1478 		 * module.
1479 		 */
1480 		case IP_MULTICAST_IF:
1481 		case IP_MULTICAST_VIF:
1482 		case IP_MULTICAST_TTL:
1483 		case IP_MULTICAST_LOOP:
1484 		case IP_MSFILTER:
1485 			error = inp_getmoptions(inp, sopt);
1486 			break;
1487 
1488 #if defined(IPSEC) || defined(IPSEC_SUPPORT)
1489 		case IP_IPSEC_POLICY:
1490 			if (IPSEC_ENABLED(ipv4)) {
1491 				error = IPSEC_PCBCTL(ipv4, inp, sopt);
1492 				break;
1493 			}
1494 			/* FALLTHROUGH */
1495 #endif /* IPSEC */
1496 
1497 		default:
1498 			error = ENOPROTOOPT;
1499 			break;
1500 		}
1501 		break;
1502 	}
1503 	return (error);
1504 }
1505 
1506 /*
1507  * Routine called from ip_output() to loop back a copy of an IP multicast
1508  * packet to the input queue of a specified interface.  Note that this
1509  * calls the output routine of the loopback "driver", but with an interface
1510  * pointer that might NOT be a loopback interface -- evil, but easier than
1511  * replicating that code here.
1512  */
1513 static void
1514 ip_mloopback(struct ifnet *ifp, const struct mbuf *m, int hlen)
1515 {
1516 	struct ip *ip;
1517 	struct mbuf *copym;
1518 
1519 	/*
1520 	 * Make a deep copy of the packet because we're going to
1521 	 * modify the pack in order to generate checksums.
1522 	 */
1523 	copym = m_dup(m, M_NOWAIT);
1524 	if (copym != NULL && (!M_WRITABLE(copym) || copym->m_len < hlen))
1525 		copym = m_pullup(copym, hlen);
1526 	if (copym != NULL) {
1527 		/* If needed, compute the checksum and mark it as valid. */
1528 		if (copym->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
1529 			in_delayed_cksum(copym);
1530 			copym->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
1531 			copym->m_pkthdr.csum_flags |=
1532 			    CSUM_DATA_VALID | CSUM_PSEUDO_HDR;
1533 			copym->m_pkthdr.csum_data = 0xffff;
1534 		}
1535 		/*
1536 		 * We don't bother to fragment if the IP length is greater
1537 		 * than the interface's MTU.  Can this possibly matter?
1538 		 */
1539 		ip = mtod(copym, struct ip *);
1540 		ip->ip_sum = 0;
1541 		ip->ip_sum = in_cksum(copym, hlen);
1542 		if_simloop(ifp, copym, AF_INET, 0);
1543 	}
1544 }
1545