xref: /xnu-11215.41.3/bsd/netinet6/udp6_output.c (revision 33de042d024d46de5ff4e89f2471de6608e37fa4)
1 /*
2  * Copyright (c) 2000-2024 Apple Inc. All rights reserved.
3  *
4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
5  *
6  * This file contains Original Code and/or Modifications of Original Code
7  * as defined in and that are subject to the Apple Public Source License
8  * Version 2.0 (the 'License'). You may not use this file except in
9  * compliance with the License. The rights granted to you under the License
10  * may not be used to create, or enable the creation or redistribution of,
11  * unlawful or unlicensed copies of an Apple operating system, or to
12  * circumvent, violate, or enable the circumvention or violation of, any
13  * terms of an Apple operating system software license agreement.
14  *
15  * Please obtain a copy of the License at
16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
17  *
18  * The Original Code and all software distributed under the License are
19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
23  * Please see the License for the specific language governing rights and
24  * limitations under the License.
25  *
26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
27  */
28 
29 
30 /*	$FreeBSD: src/sys/netinet6/udp6_output.c,v 1.1.2.3 2001/08/31 13:49:58 jlemon Exp $	*/
31 /*	$KAME: udp6_output.c,v 1.31 2001/05/21 16:39:15 jinmei Exp $	*/
32 
33 /*
34  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
35  * All rights reserved.
36  *
37  * Redistribution and use in source and binary forms, with or without
38  * modification, are permitted provided that the following conditions
39  * are met:
40  * 1. Redistributions of source code must retain the above copyright
41  *    notice, this list of conditions and the following disclaimer.
42  * 2. Redistributions in binary form must reproduce the above copyright
43  *    notice, this list of conditions and the following disclaimer in the
44  *    documentation and/or other materials provided with the distribution.
45  * 3. Neither the name of the project nor the names of its contributors
46  *    may be used to endorse or promote products derived from this software
47  *    without specific prior written permission.
48  *
49  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
50  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
51  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
52  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
53  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
54  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
55  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
56  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
57  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
58  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
59  * SUCH DAMAGE.
60  */
61 
62 /*
63  * Copyright (c) 1982, 1986, 1989, 1993
64  *	The Regents of the University of California.  All rights reserved.
65  *
66  * Redistribution and use in source and binary forms, with or without
67  * modification, are permitted provided that the following conditions
68  * are met:
69  * 1. Redistributions of source code must retain the above copyright
70  *    notice, this list of conditions and the following disclaimer.
71  * 2. Redistributions in binary form must reproduce the above copyright
72  *    notice, this list of conditions and the following disclaimer in the
73  *    documentation and/or other materials provided with the distribution.
74  * 3. All advertising materials mentioning features or use of this software
75  *    must display the following acknowledgement:
76  *	This product includes software developed by the University of
77  *	California, Berkeley and its contributors.
78  * 4. Neither the name of the University nor the names of its contributors
79  *    may be used to endorse or promote products derived from this software
80  *    without specific prior written permission.
81  *
82  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
83  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
84  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
85  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
86  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
87  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
88  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
89  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
90  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
91  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
92  * SUCH DAMAGE.
93  *
94  *	@(#)udp_var.h	8.1 (Berkeley) 6/10/93
95  */
96 
97 #include <sys/param.h>
98 #include <sys/malloc.h>
99 #include <sys/mbuf.h>
100 #include <sys/protosw.h>
101 #include <sys/socket.h>
102 #include <sys/socketvar.h>
103 #include <sys/sysctl.h>
104 #include <sys/errno.h>
105 #include <sys/stat.h>
106 #include <sys/systm.h>
107 #include <sys/proc.h>
108 #include <sys/syslog.h>
109 
110 #include <machine/endian.h>
111 
112 #include <net/if.h>
113 #include <net/route.h>
114 #include <net/if_types.h>
115 #include <net/ntstat.h>
116 #include <net/droptap.h>
117 
118 #include <netinet/in.h>
119 #include <netinet/in_var.h>
120 #include <netinet/in_systm.h>
121 #include <netinet/in_tclass.h>
122 #include <netinet/ip.h>
123 #include <netinet/ip_var.h>
124 #include <netinet/in_pcb.h>
125 #include <netinet/udp.h>
126 #include <netinet/udp_var.h>
127 #include <netinet/ip6.h>
128 #include <netinet6/ip6_var.h>
129 #include <netinet6/in6_pcb.h>
130 #include <netinet6/udp6_var.h>
131 #include <netinet/icmp6.h>
132 #include <netinet6/ip6protosw.h>
133 
134 #if NECP
135 #include <net/necp.h>
136 #endif /* NECP */
137 
138 #include <net/net_osdep.h>
139 
140 #if CONTENT_FILTER
141 #include <net/content_filter.h>
142 #endif /* CONTENT_FILTER */
143 
144 #include <net/sockaddr_utils.h>
145 
146 /*
147  * UDP protocol inplementation.
148  * Per RFC 768, August, 1980.
149  */
150 int
udp6_output(struct in6pcb * in6p,struct mbuf * m,struct sockaddr * addr6,struct mbuf * control,struct proc * p)151 udp6_output(struct in6pcb *in6p, struct mbuf *m, struct sockaddr *addr6,
152     struct mbuf *control, struct proc *p)
153 {
154 	u_int32_t ulen = m->m_pkthdr.len;
155 	u_int32_t plen = sizeof(struct udphdr) + ulen;
156 	struct ip6_hdr *ip6;
157 	struct udphdr *__single udp6;
158 	struct in6_addr *__single laddr, *__single faddr;
159 	u_short fport;
160 	int error = 0;
161 	struct ip6_pktopts opt, *__single optp = NULL;
162 	struct ip6_moptions *__single im6o;
163 	int af = AF_INET6, hlen = sizeof(struct ip6_hdr);
164 	int flags;
165 	struct sockaddr_in6 tmp;
166 	struct in6_addr storage;
167 	int sotc = SO_TC_UNSPEC;
168 	int netsvctype = _NET_SERVICE_TYPE_UNSPEC;
169 	struct ip6_out_args ip6oa;
170 	struct flowadv *__single adv = &ip6oa.ip6oa_flowadv;
171 	struct socket *__single so = in6p->in6p_socket;
172 	struct route_in6 ro;
173 	int flowadv = 0;
174 	bool sndinprog_cnt_used = false;
175 #if CONTENT_FILTER
176 	struct m_tag *__single cfil_tag = NULL;
177 	bool cfil_faddr_use = false;
178 	uint32_t cfil_so_state_change_cnt = 0;
179 	struct sockaddr *__single cfil_faddr = NULL;
180 	struct sockaddr_in6 *__single cfil_sin6 = NULL;
181 #endif
182 	bool check_qos_marking_again = (so->so_flags1 & SOF1_QOSMARKING_POLICY_OVERRIDE) ? FALSE : TRUE;
183 	uint32_t lifscope = IFSCOPE_NONE, fifscope = IFSCOPE_NONE;
184 	drop_reason_t drop_reason = DROP_REASON_UNSPECIFIED;
185 
186 	bzero(&ip6oa, sizeof(ip6oa));
187 	ip6oa.ip6oa_boundif = IFSCOPE_NONE;
188 	ip6oa.ip6oa_flags = IP6OAF_SELECT_SRCIF;
189 
190 	/* Enable flow advisory only when connected */
191 	flowadv = (so->so_state & SS_ISCONNECTED) ? 1 : 0;
192 
193 	if (flowadv && INP_WAIT_FOR_IF_FEEDBACK(in6p)) {
194 		error = ENOBUFS;
195 		drop_reason = DROP_REASON_IP_ENOBUFS;
196 		goto release;
197 	}
198 
199 	if (in6p->inp_flags & INP_BOUND_IF) {
200 		ip6oa.ip6oa_boundif = in6p->inp_boundifp->if_index;
201 		ip6oa.ip6oa_flags |= IP6OAF_BOUND_IF;
202 	} else if (!in6_embedded_scope && IN6_IS_SCOPE_EMBED(&in6p->in6p_faddr)) {
203 		ip6oa.ip6oa_boundif = in6p->inp_fifscope;
204 		ip6oa.ip6oa_flags |= IP6OAF_BOUND_IF;
205 	}
206 	if (INP_NO_CELLULAR(in6p)) {
207 		ip6oa.ip6oa_flags |= IP6OAF_NO_CELLULAR;
208 	}
209 	if (INP_NO_EXPENSIVE(in6p)) {
210 		ip6oa.ip6oa_flags |= IP6OAF_NO_EXPENSIVE;
211 	}
212 	if (INP_NO_CONSTRAINED(in6p)) {
213 		ip6oa.ip6oa_flags |= IP6OAF_NO_CONSTRAINED;
214 	}
215 	if (INP_AWDL_UNRESTRICTED(in6p)) {
216 		ip6oa.ip6oa_flags |= IP6OAF_AWDL_UNRESTRICTED;
217 	}
218 	if (INP_INTCOPROC_ALLOWED(in6p)) {
219 		ip6oa.ip6oa_flags |= IP6OAF_INTCOPROC_ALLOWED;
220 	}
221 	if (INP_MANAGEMENT_ALLOWED(in6p)) {
222 		ip6oa.ip6oa_flags |= IP6OAF_MANAGEMENT_ALLOWED;
223 	}
224 
225 #if CONTENT_FILTER
226 	/*
227 	 * If socket is subject to UDP Content Filter and no addr is passed in,
228 	 * retrieve CFIL saved state from mbuf and use it if necessary.
229 	 */
230 	if (CFIL_DGRAM_FILTERED(so) && !addr6) {
231 		cfil_tag = cfil_dgram_get_socket_state(m, &cfil_so_state_change_cnt, NULL, &cfil_faddr, NULL);
232 		if (cfil_tag) {
233 			cfil_sin6 = SIN6(cfil_faddr);
234 			if ((so->so_state_change_cnt != cfil_so_state_change_cnt) &&
235 			    (in6p->in6p_fport != cfil_sin6->sin6_port ||
236 			    !in6_are_addr_equal_scoped(&in6p->in6p_faddr, &cfil_sin6->sin6_addr, in6p->inp_fifscope, cfil_sin6->sin6_scope_id))) {
237 				/*
238 				 * Socket is connected but socket state and dest addr/port changed.
239 				 * We need to use the saved faddr info.
240 				 */
241 				cfil_faddr_use = true;
242 			}
243 		}
244 	}
245 #endif
246 
247 	if (control) {
248 		sotc = so_tc_from_control(control, &netsvctype);
249 		if ((error = ip6_setpktopts(control, &opt,
250 		    in6p->in6p_outputopts, IPPROTO_UDP)) != 0) {
251 			drop_reason = DROP_REASON_IP6_BAD_OPTION;
252 			goto release;
253 		}
254 		optp = &opt;
255 	} else {
256 		optp = in6p->in6p_outputopts;
257 	}
258 
259 	if (sotc == SO_TC_UNSPEC) {
260 		sotc = so->so_traffic_class;
261 		netsvctype = so->so_netsvctype;
262 	}
263 	ip6oa.ip6oa_sotc = sotc;
264 	ip6oa.ip6oa_netsvctype = netsvctype;
265 
266 	in6p->inp_sndinprog_cnt++;
267 	sndinprog_cnt_used = true;
268 
269 	if (addr6) {
270 		/*
271 		 * IPv4 version of udp_output calls in_pcbconnect in this case,
272 		 * which has its costs.
273 		 *
274 		 * Since we saw no essential reason for calling in_pcbconnect,
275 		 * we get rid of such kind of logic, and call in6_selectsrc
276 		 * and in6_pcbsetport in order to fill in the local address
277 		 * and the local port.
278 		 */
279 		struct sockaddr_in6 *__single sin6 = SIN6(addr6);
280 
281 		if (sin6->sin6_port == 0) {
282 			error = EADDRNOTAVAIL;
283 			drop_reason = DROP_REASON_IP_DST_ADDR_NO_AVAIL;
284 			goto release;
285 		}
286 
287 		if (!IN6_IS_ADDR_UNSPECIFIED(&in6p->in6p_faddr)) {
288 			/* how about ::ffff:0.0.0.0 case? */
289 			error = EISCONN;
290 			drop_reason = DROP_REASON_IP_EISCONN;
291 			goto release;
292 		}
293 
294 		/* protect *sin6 from overwrites */
295 		tmp = *sin6;
296 		sin6 = &tmp;
297 
298 		faddr = &sin6->sin6_addr;
299 		fport = sin6->sin6_port; /* allow 0 port */
300 
301 		if (IN6_IS_ADDR_V4MAPPED(faddr)) {
302 			if ((in6p->in6p_flags & IN6P_IPV6_V6ONLY)) {
303 				/*
304 				 * I believe we should explicitly discard the
305 				 * packet when mapped addresses are disabled,
306 				 * rather than send the packet as an IPv6 one.
307 				 * If we chose the latter approach, the packet
308 				 * might be sent out on the wire based on the
309 				 * default route, the situation which we'd
310 				 * probably want to avoid.
311 				 * (20010421 [email protected])
312 				 */
313 				error = EINVAL;
314 				drop_reason = DROP_REASON_IP6_ONLY;
315 				goto release;
316 			} else {
317 				af = AF_INET;
318 			}
319 		}
320 
321 		/* KAME hack: embed scopeid */
322 		if (in6_embedscope(&sin6->sin6_addr, sin6, in6p, NULL,
323 		    optp, IN6_NULL_IF_EMBEDDED_SCOPE(&sin6->sin6_scope_id)) != 0) {
324 			error = EINVAL;
325 			drop_reason = DROP_REASON_IP6_BAD_SCOPE;
326 			goto release;
327 		}
328 		fifscope = sin6->sin6_scope_id;
329 
330 		if (!IN6_IS_ADDR_V4MAPPED(faddr)) {
331 			struct ifnet *__single src_ifp = NULL;
332 			laddr = in6_selectsrc(sin6, optp,
333 			    in6p, &in6p->in6p_route, &src_ifp, &storage,
334 			    ip6oa.ip6oa_boundif, &error);
335 			if (src_ifp != NULL) {
336 				lifscope = src_ifp->if_index;
337 				ifnet_release(src_ifp);
338 			}
339 		} else {
340 			laddr = &in6p->in6p_laddr;      /* XXX */
341 			lifscope = in6p->inp_lifscope;
342 		}
343 		if (laddr == NULL) {
344 			if (error == 0) {
345 				error = EADDRNOTAVAIL;
346 			}
347 			drop_reason = DROP_REASON_IP_SRC_ADDR_NO_AVAIL;
348 			goto release;
349 		}
350 		if (in6p->in6p_lport == 0 &&
351 		    (error = in6_pcbsetport(laddr, addr6, in6p, p, 0)) != 0) {
352 			goto release;
353 		}
354 	} else {
355 		if (IN6_IS_ADDR_UNSPECIFIED(&in6p->in6p_faddr)) {
356 			error = ENOTCONN;
357 			drop_reason = DROP_REASON_IP6_ADDR_UNSPECIFIED;
358 			goto release;
359 		}
360 		laddr = &in6p->in6p_laddr;
361 		faddr = &in6p->in6p_faddr;
362 		fport = in6p->in6p_fport;
363 		fifscope = in6p->inp_fifscope;
364 		lifscope = in6p->inp_lifscope;
365 #if CONTENT_FILTER
366 		if (cfil_faddr_use) {
367 			faddr = &SIN6(cfil_faddr)->sin6_addr;
368 			fport = SIN6(cfil_faddr)->sin6_port;
369 			fifscope = SIN6(cfil_faddr)->sin6_scope_id;
370 
371 			/* Do not use cached route */
372 			ROUTE_RELEASE(&in6p->in6p_route);
373 		}
374 #endif
375 		if (IN6_IS_ADDR_V4MAPPED(faddr)) {
376 			if ((in6p->in6p_flags & IN6P_IPV6_V6ONLY)) {
377 				/*
378 				 * XXX: this case would happen when the
379 				 * application sets the V6ONLY flag after
380 				 * connecting the foreign address.
381 				 * Such applications should be fixed,
382 				 * so we bark here.
383 				 */
384 				log(LOG_INFO, "udp6_output: IPV6_V6ONLY "
385 				    "option was set for a connected socket\n");
386 				error = EINVAL;
387 				goto release;
388 			} else {
389 				af = AF_INET;
390 			}
391 		}
392 	}
393 
394 	if (in6p->inp_flowhash == 0) {
395 		inp_calc_flowhash(in6p);
396 		ASSERT(in6p->inp_flowhash != 0);
397 	}
398 	/* update flowinfo - RFC 6437 */
399 	if (in6p->inp_flow == 0 && in6p->in6p_flags & IN6P_AUTOFLOWLABEL) {
400 		in6p->inp_flow &= ~IPV6_FLOWLABEL_MASK;
401 		in6p->inp_flow |=
402 		    (htonl(ip6_randomflowlabel()) & IPV6_FLOWLABEL_MASK);
403 	}
404 
405 	if (af == AF_INET) {
406 		hlen = sizeof(struct ip);
407 	}
408 
409 	if (fport == htons(53) && !(so->so_flags1 & SOF1_DNS_COUNTED)) {
410 		so->so_flags1 |= SOF1_DNS_COUNTED;
411 		INC_ATOMIC_INT64_LIM(net_api_stats.nas_socket_inet_dgram_dns);
412 	}
413 
414 	/*
415 	 * Calculate data length and get a mbuf
416 	 * for UDP and IP6 headers.
417 	 */
418 	M_PREPEND(m, hlen + sizeof(struct udphdr), M_DONTWAIT, 1);
419 	if (m == 0) {
420 		error = ENOBUFS;
421 		drop_reason = DROP_REASON_IP_ENOBUFS;
422 		goto release;
423 	}
424 
425 	/*
426 	 * Stuff checksum and output datagram.
427 	 */
428 	udp6 = (struct udphdr *)(void *)(mtod(m, caddr_t) + hlen);
429 	udp6->uh_sport = in6p->in6p_lport; /* lport is always set in the PCB */
430 	udp6->uh_dport = fport;
431 	if (plen <= 0xffff) {
432 		udp6->uh_ulen = htons((u_short)plen);
433 	} else {
434 		udp6->uh_ulen = 0;
435 	}
436 	udp6->uh_sum = 0;
437 
438 	switch (af) {
439 	case AF_INET6:
440 		ip6 = mtod(m, struct ip6_hdr *);
441 		ip6->ip6_flow   = in6p->inp_flow & IPV6_FLOWINFO_MASK;
442 		ip6->ip6_vfc    &= ~IPV6_VERSION_MASK;
443 		ip6->ip6_vfc    |= IPV6_VERSION;
444 #if 0           /* ip6_plen will be filled in ip6_output. */
445 		ip6->ip6_plen   = htons((u_short)plen);
446 #endif
447 		ip6->ip6_nxt    = IPPROTO_UDP;
448 		ip6->ip6_hlim   = in6_selecthlim(in6p, in6p->in6p_route.ro_rt ?
449 		    in6p->in6p_route.ro_rt->rt_ifp : NULL);
450 		ip6->ip6_src    = *laddr;
451 		ip6->ip6_dst    = *faddr;
452 
453 		udp6->uh_sum = in6_pseudo(laddr, faddr,
454 		    htonl(plen + IPPROTO_UDP));
455 		m->m_pkthdr.csum_flags = (CSUM_UDPIPV6 | CSUM_ZERO_INVERT);
456 		m->m_pkthdr.csum_data = offsetof(struct udphdr, uh_sum);
457 
458 		if (!IN6_IS_ADDR_UNSPECIFIED(laddr)) {
459 			ip6oa.ip6oa_flags |= IP6OAF_BOUND_SRCADDR;
460 		}
461 
462 		flags = IPV6_OUTARGS;
463 
464 		udp6stat.udp6s_opackets++;
465 
466 #if NECP
467 		{
468 			necp_kernel_policy_id policy_id;
469 			necp_kernel_policy_id skip_policy_id;
470 			u_int32_t route_rule_id;
471 			u_int32_t pass_flags;
472 
473 			/*
474 			 * We need a route to perform NECP route rule checks
475 			 */
476 			if (net_qos_policy_restricted != 0 &&
477 			    ROUTE_UNUSABLE(&in6p->inp_route)) {
478 				struct sockaddr_in6 to;
479 				struct sockaddr_in6 from;
480 
481 				ROUTE_RELEASE(&in6p->inp_route);
482 
483 				SOCKADDR_ZERO(&from, sizeof(struct sockaddr_in6));
484 				from.sin6_family = AF_INET6;
485 				from.sin6_len = sizeof(struct sockaddr_in6);
486 				from.sin6_addr = *laddr;
487 
488 				SOCKADDR_ZERO(&to, sizeof(struct sockaddr_in6));
489 				to.sin6_family = AF_INET6;
490 				to.sin6_len = sizeof(struct sockaddr_in6);
491 				to.sin6_addr = *faddr;
492 
493 				in6p->inp_route.ro_dst.sa_family = AF_INET6;
494 				in6p->inp_route.ro_dst.sa_len = sizeof(struct sockaddr_in6);
495 				SIN6(&in6p->inp_route.ro_dst)->sin6_addr = *faddr;
496 
497 				if (!in6_embedded_scope) {
498 					SIN6(&in6p->inp_route.ro_dst)->sin6_scope_id =
499 					    IN6_IS_SCOPE_EMBED(faddr) ? fifscope : IFSCOPE_NONE;
500 				}
501 				rtalloc_scoped(&in6p->inp_route, ip6oa.ip6oa_boundif);
502 
503 				inp_update_necp_policy(in6p, SA(&from),
504 				    SA(&to), ip6oa.ip6oa_boundif);
505 				in6p->inp_policyresult.results.qos_marking_gencount = 0;
506 			}
507 
508 			if (!necp_socket_is_allowed_to_send_recv_v6(in6p, in6p->in6p_lport, fport, laddr, faddr, NULL, 0, &policy_id, &route_rule_id, &skip_policy_id, &pass_flags)) {
509 				error = EHOSTUNREACH;
510 				drop_reason = DROP_REASON_IP_NECP_POLICY_DROP;
511 				goto release;
512 			}
513 
514 			necp_mark_packet_from_socket(m, in6p, policy_id, route_rule_id, skip_policy_id, pass_flags);
515 
516 			if (net_qos_policy_restricted != 0) {
517 				necp_socket_update_qos_marking(in6p, in6p->in6p_route.ro_rt, route_rule_id);
518 			}
519 		}
520 #endif /* NECP */
521 		if ((so->so_flags1 & SOF1_QOSMARKING_ALLOWED)) {
522 			ip6oa.ip6oa_flags |= IP6OAF_QOSMARKING_ALLOWED;
523 		}
524 		if (check_qos_marking_again) {
525 			ip6oa.ip6oa_flags |= IP6OAF_REDO_QOSMARKING_POLICY;
526 		}
527 		ip6oa.qos_marking_gencount = in6p->inp_policyresult.results.qos_marking_gencount;
528 
529 #if IPSEC
530 		if (in6p->in6p_sp != NULL && ipsec_setsocket(m, so) != 0) {
531 			error = ENOBUFS;
532 			drop_reason = DROP_REASON_IP_ENOBUFS;
533 			goto release;
534 		}
535 #endif /*IPSEC*/
536 
537 		/* In case of IPv4-mapped address used in previous send */
538 		if (ROUTE_UNUSABLE(&in6p->in6p_route) ||
539 		    rt_key(in6p->in6p_route.ro_rt)->sa_family != AF_INET6) {
540 			ROUTE_RELEASE(&in6p->in6p_route);
541 		}
542 
543 		/* Copy the cached route and take an extra reference */
544 		in6p_route_copyout(in6p, &ro);
545 
546 		set_packet_service_class(m, so, sotc, PKT_SCF_IPV6);
547 
548 		m->m_pkthdr.pkt_flowsrc = FLOWSRC_INPCB;
549 		m->m_pkthdr.pkt_flowid = in6p->inp_flowhash;
550 		m->m_pkthdr.pkt_proto = IPPROTO_UDP;
551 		m->m_pkthdr.pkt_flags |= (PKTF_FLOW_ID | PKTF_FLOW_LOCALSRC);
552 		if (flowadv) {
553 			m->m_pkthdr.pkt_flags |= PKTF_FLOW_ADV;
554 		}
555 		m->m_pkthdr.tx_udp_pid = so->last_pid;
556 		if (so->so_flags & SOF_DELEGATED) {
557 			m->m_pkthdr.tx_udp_e_pid = so->e_pid;
558 		} else {
559 			m->m_pkthdr.tx_udp_e_pid = 0;
560 		}
561 #if (DEBUG || DEVELOPMENT)
562 		if (so->so_flags & SOF_MARK_WAKE_PKT) {
563 			so->so_flags &= ~SOF_MARK_WAKE_PKT;
564 			m->m_pkthdr.pkt_flags |= PKTF_WAKE_PKT;
565 		}
566 #endif /* (DEBUG || DEVELOPMENT) */
567 
568 		im6o = in6p->in6p_moptions;
569 		if (im6o != NULL) {
570 			IM6O_LOCK(im6o);
571 			IM6O_ADDREF_LOCKED(im6o);
572 			if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst) &&
573 			    im6o->im6o_multicast_ifp != NULL) {
574 				in6p->in6p_last_outifp =
575 				    im6o->im6o_multicast_ifp;
576 #if SKYWALK
577 				if (NETNS_TOKEN_VALID(&in6p->inp_netns_token)) {
578 					netns_set_ifnet(&in6p->inp_netns_token,
579 					    in6p->in6p_last_outifp);
580 				}
581 #endif /* SKYWALK */
582 			}
583 			IM6O_UNLOCK(im6o);
584 		}
585 
586 		ip6_output_setdstifscope(m, fifscope, NULL);
587 		ip6_output_setsrcifscope(m, lifscope, NULL);
588 
589 		socket_unlock(so, 0);
590 		error = ip6_output(m, optp, &ro, flags, im6o, NULL, &ip6oa);
591 		m = NULL;
592 		socket_lock(so, 0);
593 
594 		if (im6o != NULL) {
595 			IM6O_REMREF(im6o);
596 		}
597 
598 		if (check_qos_marking_again) {
599 			in6p->inp_policyresult.results.qos_marking_gencount = ip6oa.qos_marking_gencount;
600 			if (ip6oa.ip6oa_flags & IP6OAF_QOSMARKING_ALLOWED) {
601 				in6p->inp_socket->so_flags1 |= SOF1_QOSMARKING_ALLOWED;
602 			} else {
603 				in6p->inp_socket->so_flags1 &= ~SOF1_QOSMARKING_ALLOWED;
604 			}
605 		}
606 
607 		if (error == 0 && nstat_collect) {
608 			stats_functional_type ifnet_count_type = stats_functional_type_none;
609 
610 			if (in6p->in6p_route.ro_rt != NULL) {
611 				ifnet_count_type = IFNET_COUNT_TYPE(in6p->in6p_route.
612 				    ro_rt->rt_ifp);
613 			}
614 			INP_ADD_STAT(in6p, ifnet_count_type, txpackets, 1);
615 			INP_ADD_STAT(in6p, ifnet_count_type, txbytes, ulen);
616 			inp_set_activity_bitmap(in6p);
617 		}
618 
619 		if (flowadv && (adv->code == FADV_FLOW_CONTROLLED ||
620 		    adv->code == FADV_SUSPENDED)) {
621 			/*
622 			 * Return an error to indicate
623 			 * that the packet has been dropped.
624 			 */
625 			error = ENOBUFS;
626 			inp_set_fc_state(in6p, adv->code);
627 		}
628 
629 		if (ro.ro_rt != NULL) {
630 			struct ifnet *__single outif = ro.ro_rt->rt_ifp;
631 
632 			so->so_pktheadroom = (uint16_t)P2ROUNDUP(
633 				sizeof(struct udphdr) +
634 				hlen +
635 				ifnet_hdrlen(outif) +
636 				ifnet_mbuf_packetpreamblelen(outif),
637 				sizeof(u_int32_t));
638 		}
639 
640 		/* Synchronize PCB cached route */
641 		in6p_route_copyin(in6p, &ro);
642 
643 		if (in6p->in6p_route.ro_rt != NULL) {
644 			struct rtentry *__single rt = in6p->in6p_route.ro_rt;
645 			struct ifnet *__single outif;
646 
647 			if (IS_LOCALNET_ROUTE(rt)) {
648 				in6p->in6p_flags2 |= INP2_LAST_ROUTE_LOCAL;
649 			} else {
650 				in6p->in6p_flags2 &= ~INP2_LAST_ROUTE_LOCAL;
651 			}
652 
653 			if (rt->rt_flags & RTF_MULTICAST) {
654 				rt = NULL;      /* unusable */
655 			}
656 #if CONTENT_FILTER
657 			/*
658 			 * Discard temporary route for cfil case
659 			 */
660 			if (cfil_faddr_use) {
661 				rt = NULL;      /* unusable */
662 			}
663 #endif
664 
665 			/*
666 			 * Always discard the cached route for unconnected
667 			 * socket or if it is a multicast route.
668 			 */
669 			if (rt == NULL) {
670 				ROUTE_RELEASE(&in6p->in6p_route);
671 			}
672 
673 			/*
674 			 * If the destination route is unicast, update outif
675 			 * with that of the route interface used by IP.
676 			 */
677 			if (rt != NULL) {
678 				/*
679 				 * When an NECP IP tunnel policy forces the outbound interface,
680 				 * ip6_output_list() informs the transport layer what is the actual
681 				 * outgoing interface
682 				 */
683 				if (ip6oa.ip6oa_flags & IP6OAF_BOUND_IF) {
684 					outif = ifindex2ifnet[ip6oa.ip6oa_boundif];
685 				} else {
686 					outif = rt->rt_ifp;
687 				}
688 				if (outif != NULL && outif != in6p->in6p_last_outifp) {
689 					in6p->in6p_last_outifp = outif;
690 #if SKYWALK
691 					if (NETNS_TOKEN_VALID(&in6p->inp_netns_token)) {
692 						netns_set_ifnet(&in6p->inp_netns_token,
693 						    in6p->in6p_last_outifp);
694 					}
695 #endif /* SKYWALK */
696 
697 					so->so_pktheadroom = (uint16_t)P2ROUNDUP(
698 						sizeof(struct udphdr) +
699 						hlen +
700 						ifnet_hdrlen(outif) +
701 						ifnet_mbuf_packetpreamblelen(outif),
702 						sizeof(u_int32_t));
703 				}
704 			}
705 		} else {
706 			ROUTE_RELEASE(&in6p->in6p_route);
707 		}
708 
709 		/*
710 		 * If output interface was cellular/expensive, and this
711 		 * socket is denied access to it, generate an event.
712 		 */
713 		if (error != 0 && (ip6oa.ip6oa_flags & IP6OAF_R_IFDENIED) &&
714 		    (INP_NO_CELLULAR(in6p) || INP_NO_EXPENSIVE(in6p) || INP_NO_CONSTRAINED(in6p))) {
715 			soevent(in6p->inp_socket, (SO_FILT_HINT_LOCKED |
716 			    SO_FILT_HINT_IFDENIED));
717 		}
718 		break;
719 	case AF_INET:
720 		error = EAFNOSUPPORT;
721 		drop_reason = DROP_REASON_IP_EAFNOSUPPORT;
722 		goto release;
723 	}
724 	goto releaseopt;
725 
726 release:
727 
728 	if (m != NULL) {
729 		m_drop(m, DROPTAP_FLAG_DIR_OUT | DROPTAP_FLAG_L2_MISSING, drop_reason, NULL, 0);
730 	}
731 
732 releaseopt:
733 	if (control != NULL) {
734 		if (optp == &opt) {
735 			ip6_clearpktopts(optp, -1);
736 		}
737 		m_freem(control);
738 	}
739 #if CONTENT_FILTER
740 	if (cfil_tag) {
741 		m_tag_free(cfil_tag);
742 	}
743 #endif
744 	if (sndinprog_cnt_used) {
745 		VERIFY(in6p->inp_sndinprog_cnt > 0);
746 		if (--in6p->inp_sndinprog_cnt == 0) {
747 			in6p->inp_flags &= ~(INP_FC_FEEDBACK);
748 			if (in6p->inp_sndingprog_waiters > 0) {
749 				wakeup(&in6p->inp_sndinprog_cnt);
750 			}
751 		}
752 		sndinprog_cnt_used = false;
753 	}
754 
755 	return error;
756 }
757