priv.c revision 1.17
1/*	$OpenBSD: priv.c,v 1.17 2021/03/29 23:37:01 dv Exp $	*/
2
3/*
4 * Copyright (c) 2016 Reyk Floeter <reyk@openbsd.org>
5 *
6 * Permission to use, copy, modify, and distribute this software for any
7 * purpose with or without fee is hereby granted, provided that the above
8 * copyright notice and this permission notice appear in all copies.
9 *
10 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
11 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
12 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
13 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
14 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
15 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
16 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
17 */
18
19#include <sys/param.h>	/* nitems */
20#include <sys/queue.h>
21#include <sys/stat.h>
22#include <sys/socket.h>
23#include <sys/un.h>
24#include <sys/ioctl.h>
25#include <sys/tree.h>
26
27#include <net/if.h>
28#include <netinet/in.h>
29#include <netinet/if_ether.h>
30#include <netinet6/in6_var.h>
31#include <netinet6/nd6.h>
32#include <net/if_bridge.h>
33
34#include <arpa/inet.h>
35
36#include <errno.h>
37#include <event.h>
38#include <fcntl.h>
39#include <stdlib.h>
40#include <stdio.h>
41#include <string.h>
42#include <unistd.h>
43#include <signal.h>
44#include <ctype.h>
45
46#include "proc.h"
47#include "vmd.h"
48
49int	 priv_dispatch_parent(int, struct privsep_proc *, struct imsg *);
50void	 priv_run(struct privsep *, struct privsep_proc *, void *);
51
52static struct privsep_proc procs[] = {
53	{ "parent",	PROC_PARENT,	priv_dispatch_parent }
54};
55
56void
57priv(struct privsep *ps, struct privsep_proc *p)
58{
59	proc_run(ps, p, procs, nitems(procs), priv_run, NULL);
60}
61
62void
63priv_run(struct privsep *ps, struct privsep_proc *p, void *arg)
64{
65	struct vmd		*env = ps->ps_env;
66
67	/*
68	 * no pledge(2) in the "priv" process:
69	 * write ioctls are not permitted by pledge.
70	 */
71
72	/* Open our own socket for generic interface ioctls */
73	if ((env->vmd_fd = socket(AF_INET, SOCK_DGRAM, 0)) == -1)
74		fatal("socket");
75
76	/* But we need a different fd for IPv6 */
77	if ((env->vmd_fd6 = socket(AF_INET6, SOCK_DGRAM, 0)) == -1)
78		fatal("socket6");
79}
80
81int
82priv_dispatch_parent(int fd, struct privsep_proc *p, struct imsg *imsg)
83{
84	const char		*desct[] = { "tap", "switch", "bridge",
85				     "veb", NULL };
86	struct privsep		*ps = p->p_ps;
87	struct vmop_ifreq	 vfr;
88	struct vmd		*env = ps->ps_env;
89	struct ifreq		 ifr;
90	struct ifbreq		 ifbr;
91	struct ifgroupreq	 ifgr;
92	struct ifaliasreq	 ifra;
93	struct in6_aliasreq	 in6_ifra;
94	struct if_afreq		 ifar;
95	struct vmop_addr_req	 vareq;
96	struct vmop_addr_result	 varesult;
97	char			 type[IF_NAMESIZE];
98
99	switch (imsg->hdr.type) {
100	case IMSG_VMDOP_PRIV_IFDESCR:
101	case IMSG_VMDOP_PRIV_IFRDOMAIN:
102	case IMSG_VMDOP_PRIV_IFEXISTS:
103	case IMSG_VMDOP_PRIV_IFADD:
104	case IMSG_VMDOP_PRIV_IFUP:
105	case IMSG_VMDOP_PRIV_IFDOWN:
106	case IMSG_VMDOP_PRIV_IFGROUP:
107	case IMSG_VMDOP_PRIV_IFADDR:
108	case IMSG_VMDOP_PRIV_IFADDR6:
109		IMSG_SIZE_CHECK(imsg, &vfr);
110		memcpy(&vfr, imsg->data, sizeof(vfr));
111
112		/* We should not get malicious requests from the parent */
113		if (priv_getiftype(vfr.vfr_name, type, NULL) == -1 ||
114		    priv_findname(type, desct) == -1)
115			fatalx("%s: rejected priv operation on interface: %s",
116			    __func__, vfr.vfr_name);
117		break;
118	case IMSG_VMDOP_CONFIG:
119	case IMSG_CTL_RESET:
120	case IMSG_VMDOP_PRIV_GET_ADDR:
121		break;
122	default:
123		return (-1);
124	}
125
126	switch (imsg->hdr.type) {
127	case IMSG_VMDOP_PRIV_IFDESCR:
128		/* Set the interface description */
129		strlcpy(ifr.ifr_name, vfr.vfr_name, sizeof(ifr.ifr_name));
130		ifr.ifr_data = (caddr_t)vfr.vfr_value;
131		if (ioctl(env->vmd_fd, SIOCSIFDESCR, &ifr) == -1)
132			log_warn("SIOCSIFDESCR");
133		break;
134	case IMSG_VMDOP_PRIV_IFRDOMAIN:
135		strlcpy(ifr.ifr_name, vfr.vfr_name, sizeof(ifr.ifr_name));
136		ifr.ifr_rdomainid = vfr.vfr_id;
137		if (ioctl(env->vmd_fd, SIOCSIFRDOMAIN, &ifr) == -1)
138			log_warn("SIOCSIFRDOMAIN");
139		break;
140	case IMSG_VMDOP_PRIV_IFADD:
141		if (priv_getiftype(vfr.vfr_value, type, NULL) == -1)
142			fatalx("%s: rejected to add interface: %s",
143			    __func__, vfr.vfr_value);
144
145		/* Attach the device to the bridge */
146		strlcpy(ifbr.ifbr_name, vfr.vfr_name,
147		    sizeof(ifbr.ifbr_name));
148		strlcpy(ifbr.ifbr_ifsname, vfr.vfr_value,
149		    sizeof(ifbr.ifbr_ifsname));
150		if (ioctl(env->vmd_fd, SIOCBRDGADD, &ifbr) == -1 &&
151		    errno != EEXIST)
152			log_warn("SIOCBRDGADD");
153		break;
154	case IMSG_VMDOP_PRIV_IFEXISTS:
155		/* Determine if bridge/switch exists */
156		strlcpy(ifr.ifr_name, vfr.vfr_name, sizeof(ifr.ifr_name));
157		if (ioctl(env->vmd_fd, SIOCGIFFLAGS, &ifr) == -1)
158			fatalx("%s: bridge \"%s\" does not exist",
159			    __func__, vfr.vfr_name);
160		break;
161	case IMSG_VMDOP_PRIV_IFUP:
162	case IMSG_VMDOP_PRIV_IFDOWN:
163		/* Set the interface status */
164		strlcpy(ifr.ifr_name, vfr.vfr_name, sizeof(ifr.ifr_name));
165		if (ioctl(env->vmd_fd, SIOCGIFFLAGS, &ifr) == -1) {
166			log_warn("SIOCGIFFLAGS");
167			break;
168		}
169		if (imsg->hdr.type == IMSG_VMDOP_PRIV_IFUP)
170			ifr.ifr_flags |= IFF_UP;
171		else
172			ifr.ifr_flags &= ~IFF_UP;
173		if (ioctl(env->vmd_fd, SIOCSIFFLAGS, &ifr) == -1)
174			log_warn("SIOCSIFFLAGS");
175		break;
176	case IMSG_VMDOP_PRIV_IFGROUP:
177		if (priv_validgroup(vfr.vfr_value) == -1)
178			fatalx("%s: invalid group name", __func__);
179
180		if (strlcpy(ifgr.ifgr_name, vfr.vfr_name,
181		    sizeof(ifgr.ifgr_name)) >= sizeof(ifgr.ifgr_name) ||
182		    strlcpy(ifgr.ifgr_group, vfr.vfr_value,
183		    sizeof(ifgr.ifgr_group)) >= sizeof(ifgr.ifgr_group))
184			fatalx("%s: group name too long", __func__);
185
186		if (ioctl(env->vmd_fd, SIOCAIFGROUP, &ifgr) == -1 &&
187		    errno != EEXIST)
188			log_warn("SIOCAIFGROUP");
189		break;
190	case IMSG_VMDOP_PRIV_IFADDR:
191		memset(&ifra, 0, sizeof(ifra));
192
193		if (vfr.vfr_addr.ss_family != AF_INET ||
194		    vfr.vfr_addr.ss_family != vfr.vfr_mask.ss_family)
195			fatalx("%s: invalid address family", __func__);
196
197		/* Set the interface address */
198		strlcpy(ifra.ifra_name, vfr.vfr_name, sizeof(ifra.ifra_name));
199
200		ifra.ifra_addr.sa_len =
201		    ifra.ifra_mask.sa_len =
202		    sizeof(struct sockaddr_in);
203
204		memcpy(&ifra.ifra_addr, &vfr.vfr_addr,
205		    ifra.ifra_addr.sa_len);
206		memcpy(&ifra.ifra_mask, &vfr.vfr_mask,
207		    ifra.ifra_mask.sa_len);
208
209		if (ioctl(env->vmd_fd, SIOCAIFADDR, &ifra) == -1)
210			log_warn("SIOCAIFADDR");
211		break;
212	case IMSG_VMDOP_PRIV_IFADDR6:
213		memset(&ifar, 0, sizeof(ifar));
214		memset(&in6_ifra, 0, sizeof(in6_ifra));
215
216		if (vfr.vfr_addr.ss_family != AF_INET6 ||
217		    vfr.vfr_addr.ss_family != vfr.vfr_mask.ss_family)
218			fatalx("%s: invalid address family", __func__);
219
220		/* First enable IPv6 on this interface */
221		strlcpy(ifar.ifar_name, vfr.vfr_name,
222		    sizeof(ifar.ifar_name));
223		ifar.ifar_af = AF_INET6;
224		if (ioctl(env->vmd_fd, SIOCIFAFATTACH, (caddr_t)&ifar) == -1)
225			log_warn("SIOCIFAFATTACH");
226
227		/* Set the interface address */
228		strlcpy(in6_ifra.ifra_name, vfr.vfr_name,
229		    sizeof(in6_ifra.ifra_name));
230
231		in6_ifra.ifra_addr.sin6_len =
232		    in6_ifra.ifra_prefixmask.sin6_len =
233		    sizeof(struct sockaddr_in6);
234
235		memcpy(&in6_ifra.ifra_addr, &vfr.vfr_addr,
236		    in6_ifra.ifra_addr.sin6_len);
237		memcpy(&in6_ifra.ifra_prefixmask, &vfr.vfr_mask,
238		    in6_ifra.ifra_prefixmask.sin6_len);
239		in6_ifra.ifra_prefixmask.sin6_scope_id = 0;
240
241		in6_ifra.ifra_lifetime.ia6t_vltime = ND6_INFINITE_LIFETIME;
242		in6_ifra.ifra_lifetime.ia6t_pltime = ND6_INFINITE_LIFETIME;
243
244		if (ioctl(env->vmd_fd6, SIOCDIFADDR_IN6, &in6_ifra) == -1 &&
245		    errno != EADDRNOTAVAIL)
246			log_warn("SIOCDIFADDR_IN6");
247
248		if (ioctl(env->vmd_fd6, SIOCAIFADDR_IN6, &in6_ifra) == -1)
249			log_warn("SIOCAIFADDR_IN6");
250		break;
251	case IMSG_VMDOP_PRIV_GET_ADDR:
252		IMSG_SIZE_CHECK(imsg, &vareq);
253		memcpy(&vareq, imsg->data, sizeof(vareq));
254
255		varesult.var_vmid = vareq.var_vmid;
256		varesult.var_nic_idx = vareq.var_nic_idx;
257
258		/* resolve lladdr for the tap(4) and send back to parent */
259		if (ioctl(imsg->fd, SIOCGIFADDR, &varesult.var_addr) != 0)
260			log_warn("SIOCGIFADDR");
261		else
262			proc_compose_imsg(ps, PROC_PARENT, -1,
263			    IMSG_VMDOP_PRIV_GET_ADDR_RESPONSE, imsg->hdr.peerid,
264			    -1, &varesult, sizeof(varesult));
265		close(imsg->fd);
266		break;
267	case IMSG_VMDOP_CONFIG:
268		config_getconfig(env, imsg);
269		break;
270	case IMSG_CTL_RESET:
271		config_getreset(env, imsg);
272		break;
273	default:
274		return (-1);
275	}
276
277	return (0);
278}
279
280int
281priv_getiftype(char *ifname, char *type, unsigned int *unitptr)
282{
283	const char	*errstr;
284	size_t		 span;
285	unsigned int	 unit;
286
287	/* Extract the name part */
288	span = strcspn(ifname, "0123456789");
289	if (span == 0 || span >= strlen(ifname) || span >= (IF_NAMESIZE - 1))
290		return (-1);
291	memcpy(type, ifname, span);
292	type[span] = 0;
293
294	/* Now parse the unit (we don't strictly validate the format here) */
295	unit = strtonum(ifname + span, 0, UINT_MAX, &errstr);
296	if (errstr != NULL)
297		return (-1);
298	if (unitptr != NULL)
299		*unitptr = unit;
300
301	return (0);
302}
303
304int
305priv_findname(const char *name, const char **names)
306{
307	unsigned int	 i;
308
309	for (i = 0; names[i] != NULL; i++) {
310		if (strcmp(name, names[i]) == 0)
311			return (0);
312	}
313
314	return (-1);
315}
316
317int
318priv_validgroup(const char *name)
319{
320	if (strlen(name) >= IF_NAMESIZE)
321		return (-1);
322	/* Group can not end with a digit */
323	if (name[0] && isdigit(name[strlen(name) - 1]))
324		return (-1);
325	return (0);
326}
327
328/*
329 * Called from the Parent process to setup vm interface(s)
330 * - ensure the interface has the description set (tracking purposes)
331 * - if interface is to be attached to a switch, attach it
332 * - check if rdomain is set on interface and switch
333 *   - if interface only or both, use interface rdomain
334 *   - if switch only, use switch rdomain
335 * - check if group is set on interface and switch
336 *   - if interface, add it
337 *   - if switch, add it
338 * - ensure the interface is up/down
339 * - if local interface, set address
340 */
341int
342vm_priv_ifconfig(struct privsep *ps, struct vmd_vm *vm)
343{
344	char			 name[64];
345	struct vmd		*env = ps->ps_env;
346	struct vm_create_params	*vcp = &vm->vm_params.vmc_params;
347	struct vmd_if		*vif;
348	struct vmd_switch	*vsw;
349	unsigned int		 i;
350	struct vmop_ifreq	 vfr, vfbr;
351	struct sockaddr_in	*sin4;
352	struct sockaddr_in6	*sin6;
353
354	for (i = 0; i < VMM_MAX_NICS_PER_VM; i++) {
355		vif = &vm->vm_ifs[i];
356
357		if (vif->vif_name == NULL)
358			break;
359
360		memset(&vfr, 0, sizeof(vfr));
361		if (strlcpy(vfr.vfr_name, vif->vif_name,
362		    sizeof(vfr.vfr_name)) >= sizeof(vfr.vfr_name))
363			return (-1);
364
365		/* Description can be truncated */
366		(void)snprintf(vfr.vfr_value, sizeof(vfr.vfr_value),
367		    "vm%u-if%u-%s", vm->vm_vmid, i, vcp->vcp_name);
368
369		log_debug("%s: interface %s description %s", __func__,
370		    vfr.vfr_name, vfr.vfr_value);
371
372		proc_compose(ps, PROC_PRIV, IMSG_VMDOP_PRIV_IFDESCR,
373		    &vfr, sizeof(vfr));
374
375		/* set default rdomain */
376		vfr.vfr_id = getrtable();
377
378		vsw = switch_getbyname(vif->vif_switch);
379
380		/* Check if switch should exist */
381		if (vsw == NULL && vif->vif_switch != NULL)
382			log_warnx("switch \"%s\" not found", vif->vif_switch);
383
384		/* Add interface to switch and set proper rdomain */
385		if (vsw != NULL) {
386			memset(&vfbr, 0, sizeof(vfbr));
387
388			if (strlcpy(vfbr.vfr_name, vsw->sw_ifname,
389			    sizeof(vfbr.vfr_name)) >= sizeof(vfbr.vfr_name))
390				return (-1);
391			if (strlcpy(vfbr.vfr_value, vif->vif_name,
392			    sizeof(vfbr.vfr_value)) >= sizeof(vfbr.vfr_value))
393				return (-1);
394
395			log_debug("%s: switch \"%s\" interface %s add %s",
396			    __func__, vsw->sw_name, vfbr.vfr_name,
397			    vfbr.vfr_value);
398
399			proc_compose(ps, PROC_PRIV, IMSG_VMDOP_PRIV_IFADD,
400			    &vfbr, sizeof(vfbr));
401
402			/* Check rdomain properties */
403			if (vif->vif_flags & VMIFF_RDOMAIN)
404				vfr.vfr_id = vif->vif_rdomain;
405			else if (vsw->sw_flags & VMIFF_RDOMAIN)
406				vfr.vfr_id = vsw->sw_rdomain;
407		} else {
408			/* No switch to attach case */
409			if (vif->vif_flags & VMIFF_RDOMAIN)
410				vfr.vfr_id = vif->vif_rdomain;
411		}
412
413		/* Set rdomain on interface */
414		if (vfr.vfr_id != 0)
415			log_debug("%s: interface %s rdomain %u", __func__,
416			    vfr.vfr_name, vfr.vfr_id);
417
418		proc_compose(ps, PROC_PRIV, IMSG_VMDOP_PRIV_IFRDOMAIN,
419		    &vfr, sizeof(vfr));
420
421		/* First group is defined per-interface */
422		if (vif->vif_group) {
423			if (strlcpy(vfr.vfr_value, vif->vif_group,
424			    sizeof(vfr.vfr_value)) >= sizeof(vfr.vfr_value))
425				return (-1);
426
427			log_debug("%s: interface %s group %s", __func__,
428			    vfr.vfr_name, vfr.vfr_value);
429
430			proc_compose(ps, PROC_PRIV, IMSG_VMDOP_PRIV_IFGROUP,
431			    &vfr, sizeof(vfr));
432		}
433
434		/* The second group is defined per-switch */
435		if (vsw != NULL && vsw->sw_group != NULL) {
436			if (strlcpy(vfr.vfr_value, vsw->sw_group,
437			    sizeof(vfr.vfr_value)) >= sizeof(vfr.vfr_value))
438				return (-1);
439
440			log_debug("%s: interface %s group %s switch \"%s\"",
441			    __func__, vfr.vfr_name, vfr.vfr_value,
442			    vsw->sw_name);
443
444			proc_compose(ps, PROC_PRIV, IMSG_VMDOP_PRIV_IFGROUP,
445			    &vfr, sizeof(vfr));
446		}
447
448		/* Set the new interface status to up or down */
449		proc_compose(ps, PROC_PRIV, (vif->vif_flags & VMIFF_UP) ?
450		    IMSG_VMDOP_PRIV_IFUP : IMSG_VMDOP_PRIV_IFDOWN,
451		    &vfr, sizeof(vfr));
452
453		/* Set interface address if it is a local interface */
454		if (vm->vm_params.vmc_ifflags[i] & VMIFF_LOCAL) {
455			memset(&vfr.vfr_mask, 0, sizeof(vfr.vfr_mask));
456			memset(&vfr.vfr_addr, 0, sizeof(vfr.vfr_addr));
457
458			/* local IPv4 address with a /31 mask */
459			sin4 = (struct sockaddr_in *)&vfr.vfr_mask;
460			sin4->sin_family = AF_INET;
461			sin4->sin_len = sizeof(*sin4);
462			sin4->sin_addr.s_addr = htonl(0xfffffffe);
463
464			sin4 = (struct sockaddr_in *)&vfr.vfr_addr;
465			sin4->sin_family = AF_INET;
466			sin4->sin_len = sizeof(*sin4);
467			if ((sin4->sin_addr.s_addr =
468			    vm_priv_addr(&env->vmd_cfg,
469			    vm->vm_vmid, i, 0)) == 0)
470				return (-1);
471
472			inet_ntop(AF_INET, &sin4->sin_addr,
473			    name, sizeof(name));
474			log_debug("%s: interface %s address %s/31",
475			    __func__, vfr.vfr_name, name);
476
477			proc_compose(ps, PROC_PRIV, IMSG_VMDOP_PRIV_IFADDR,
478			    &vfr, sizeof(vfr));
479		}
480		if ((vm->vm_params.vmc_ifflags[i] & VMIFF_LOCAL) &&
481		    (env->vmd_cfg.cfg_flags & VMD_CFG_INET6)) {
482			memset(&vfr.vfr_mask, 0, sizeof(vfr.vfr_mask));
483			memset(&vfr.vfr_addr, 0, sizeof(vfr.vfr_addr));
484
485			/* local IPv6 address with a /96 mask */
486			sin6 = ss2sin6(&vfr.vfr_mask);
487			sin6->sin6_family = AF_INET6;
488			sin6->sin6_len = sizeof(*sin6);
489			memset(&sin6->sin6_addr.s6_addr[0], 0xff, 12);
490			memset(&sin6->sin6_addr.s6_addr[12], 0, 4);
491
492			sin6 = ss2sin6(&vfr.vfr_addr);
493			sin6->sin6_family = AF_INET6;
494			sin6->sin6_len = sizeof(*sin6);
495			if (vm_priv_addr6(&env->vmd_cfg,
496			    vm->vm_vmid, i, 0, &sin6->sin6_addr) == -1)
497				return (-1);
498
499			inet_ntop(AF_INET6, &sin6->sin6_addr,
500			    name, sizeof(name));
501			log_debug("%s: interface %s address %s/96",
502			    __func__, vfr.vfr_name, name);
503
504			proc_compose(ps, PROC_PRIV, IMSG_VMDOP_PRIV_IFADDR6,
505			    &vfr, sizeof(vfr));
506		}
507	}
508
509	return (0);
510}
511
512/*
513 * Called from the Parent process to setup underlying switch interface
514 * - ensure the interface exists
515 * - ensure the interface has the correct rdomain set
516 * - ensure the interface has the description set (tracking purposes)
517 * - ensure the interface is up/down
518 */
519int
520vm_priv_brconfig(struct privsep *ps, struct vmd_switch *vsw)
521{
522	struct vmop_ifreq	 vfr;
523
524	memset(&vfr, 0, sizeof(vfr));
525
526	if (strlcpy(vfr.vfr_name, vsw->sw_ifname,
527	    sizeof(vfr.vfr_name)) >= sizeof(vfr.vfr_name))
528		return (-1);
529
530	/* ensure bridge/switch exists */
531	proc_compose(ps, PROC_PRIV, IMSG_VMDOP_PRIV_IFEXISTS,
532	    &vfr, sizeof(vfr));
533
534	/* Use the configured rdomain or get it from the process */
535	if (vsw->sw_flags & VMIFF_RDOMAIN)
536		vfr.vfr_id = vsw->sw_rdomain;
537	else
538		vfr.vfr_id = getrtable();
539	if (vfr.vfr_id != 0)
540		log_debug("%s: interface %s rdomain %u", __func__,
541		    vfr.vfr_name, vfr.vfr_id);
542
543	/* ensure switch has the correct rodmain */
544	proc_compose(ps, PROC_PRIV, IMSG_VMDOP_PRIV_IFRDOMAIN,
545	    &vfr, sizeof(vfr));
546
547	/* Description can be truncated */
548	(void)snprintf(vfr.vfr_value, sizeof(vfr.vfr_value),
549	    "switch%u-%s", vsw->sw_id, vsw->sw_name);
550
551	log_debug("%s: interface %s description %s", __func__,
552	    vfr.vfr_name, vfr.vfr_value);
553
554	proc_compose(ps, PROC_PRIV, IMSG_VMDOP_PRIV_IFDESCR,
555	    &vfr, sizeof(vfr));
556
557	/* Set the new interface status to up or down */
558	proc_compose(ps, PROC_PRIV, (vsw->sw_flags & VMIFF_UP) ?
559	    IMSG_VMDOP_PRIV_IFUP : IMSG_VMDOP_PRIV_IFDOWN,
560	    &vfr, sizeof(vfr));
561
562	vsw->sw_running = 1;
563	return (0);
564}
565
566uint32_t
567vm_priv_addr(struct vmd_config *cfg, uint32_t vmid, int idx, int isvm)
568{
569	struct address		*h = &cfg->cfg_localprefix;
570	in_addr_t		 prefix, mask, addr;
571
572	/*
573	 * 1. Set the address prefix and mask, 100.64.0.0/10 by default.
574	 */
575	if (h->ss.ss_family != AF_INET ||
576	    h->prefixlen < 0 || h->prefixlen > 32)
577		fatal("local prefix");
578	prefix = ss2sin(&h->ss)->sin_addr.s_addr;
579	mask = prefixlen2mask(h->prefixlen);
580
581	/* 2. Encode the VM ID as a per-VM subnet range N, 100.64.N.0/24. */
582	addr = vmid << 8;
583
584	/*
585	 * 3. Assign a /31 subnet M per VM interface, 100.64.N.M/31.
586	 * Each subnet contains exactly two IP addresses; skip the
587	 * first subnet to avoid a gateway address ending with .0.
588	 */
589	addr |= (idx + 1) * 2;
590
591	/* 4. Use the first address for the gateway, the second for the VM. */
592	if (isvm)
593		addr++;
594
595	/* 5. Convert to network byte order and add the prefix. */
596	addr = htonl(addr) | prefix;
597
598	/*
599	 * Validate the results:
600	 * - the address should not exceed the prefix (eg. VM ID to high).
601	 * - up to 126 interfaces can be encoded per VM.
602	 */
603	if (prefix != (addr & mask) || idx >= 0x7f) {
604		log_warnx("%s: dhcp address range exceeded,"
605		    " vm id %u interface %d", __func__, vmid, idx);
606		return (0);
607	}
608
609	return (addr);
610}
611
612int
613vm_priv_addr6(struct vmd_config *cfg, uint32_t vmid,
614    int idx, int isvm, struct in6_addr *in6_addr)
615{
616	struct address		*h = &cfg->cfg_localprefix6;
617	struct in6_addr		 addr, mask;
618	uint32_t		 addr4;
619
620	/* 1. Set the address prefix and mask, fd00::/8 by default. */
621	if (h->ss.ss_family != AF_INET6 ||
622	    h->prefixlen < 0 || h->prefixlen > 128)
623		fatal("local prefix6");
624	addr = ss2sin6(&h->ss)->sin6_addr;
625	prefixlen2mask6(h->prefixlen, &mask);
626
627	/* 2. Encode the VM IPv4 address as subnet, fd00::NN:NN:0:0/96. */
628	if ((addr4 = vm_priv_addr(cfg, vmid, idx, 1)) == 0)
629		return (0);
630	memcpy(&addr.s6_addr[8], &addr4, sizeof(addr4));
631
632	/*
633	 * 3. Set the last octet to 1 (host) or 2 (VM).
634	 * The latter is currently not used inside vmd as we don't
635	 * answer rtsol requests ourselves.
636	 */
637	if (!isvm)
638		addr.s6_addr[15] = 1;
639	else
640		addr.s6_addr[15] = 2;
641
642	memcpy(in6_addr, &addr, sizeof(*in6_addr));
643
644	return (0);
645}
646