[qemu.git] / qemu-bridge-helper.c

/*
 * QEMU Bridge Helper
 *
 * Copyright IBM, Corp. 2011
 *
 * Authors:
 * Anthony Liguori   <aliguori@us.ibm.com>
 * Richa Marwaha     <rmarwah@linux.vnet.ibm.com>
 * Corey Bryant      <coreyb@linux.vnet.ibm.com>
 *
 * This work is licensed under the terms of the GNU GPL, version 2.  See
 * the COPYING file in the top-level directory.
 *
 */

#include "config-host.h"

#include <stdio.h>
#include <errno.h>
#include <fcntl.h>
#include <unistd.h>
#include <string.h>
#include <stdlib.h>
#include <stdbool.h>
#include <ctype.h>
#include <glib.h>

#include <sys/types.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <sys/prctl.h>

#include <net/if.h>

#include <linux/sockios.h>

#ifndef SIOCBRADDIF
#include <linux/if_bridge.h>
#endif

#include "qemu/queue.h"

#include "net/tap-linux.h"

#ifdef CONFIG_LIBCAP
#include <cap-ng.h>
#endif

#define DEFAULT_ACL_FILE CONFIG_QEMU_CONFDIR "/bridge.conf"

enum {
    ACL_ALLOW = 0,
    ACL_ALLOW_ALL,
    ACL_DENY,
    ACL_DENY_ALL,
};

typedef struct ACLRule {
    int type;
    char iface[IFNAMSIZ];
    QSIMPLEQ_ENTRY(ACLRule) entry;
} ACLRule;

typedef QSIMPLEQ_HEAD(ACLList, ACLRule) ACLList;

static void usage(void)
{
    fprintf(stderr,
            "Usage: qemu-bridge-helper [--use-vnet] --br=bridge --fd=unixfd\n");
}

static int parse_acl_file(const char *filename, ACLList *acl_list)
{
    FILE *f;
    char line[4096];
    ACLRule *acl_rule;

    f = fopen(filename, "r");
    if (f == NULL) {
        return -1;
    }

    while (fgets(line, sizeof(line), f) != NULL) {
        char *ptr = line;
        char *cmd, *arg, *argend;

        while (isspace(*ptr)) {
            ptr++;
        }

        /* skip comments and empty lines */
        if (*ptr == '#' || *ptr == 0) {
            continue;
        }

        cmd = ptr;
        arg = strchr(cmd, ' ');
        if (arg == NULL) {
            arg = strchr(cmd, '\t');
        }

        if (arg == NULL) {
            fprintf(stderr, "Invalid config line:\n  %s\n", line);
            fclose(f);
            errno = EINVAL;
            return -1;
        }

        *arg = 0;
        arg++;
        while (isspace(*arg)) {
            arg++;
        }

        argend = arg + strlen(arg);
        while (arg != argend && isspace(*(argend - 1))) {
            argend--;
        }
        *argend = 0;

        if (strcmp(cmd, "deny") == 0) {
            acl_rule = g_malloc(sizeof(*acl_rule));
            if (strcmp(arg, "all") == 0) {
                acl_rule->type = ACL_DENY_ALL;
            } else {
                acl_rule->type = ACL_DENY;
                snprintf(acl_rule->iface, IFNAMSIZ, "%s", arg);
            }
            QSIMPLEQ_INSERT_TAIL(acl_list, acl_rule, entry);
        } else if (strcmp(cmd, "allow") == 0) {
            acl_rule = g_malloc(sizeof(*acl_rule));
            if (strcmp(arg, "all") == 0) {
                acl_rule->type = ACL_ALLOW_ALL;
            } else {
                acl_rule->type = ACL_ALLOW;
                snprintf(acl_rule->iface, IFNAMSIZ, "%s", arg);
            }
            QSIMPLEQ_INSERT_TAIL(acl_list, acl_rule, entry);
        } else if (strcmp(cmd, "include") == 0) {
            /* ignore errors */
            parse_acl_file(arg, acl_list);
        } else {
            fprintf(stderr, "Unknown command `%s'\n", cmd);
            fclose(f);
            errno = EINVAL;
            return -1;
        }
    }

    fclose(f);

    return 0;
}

static bool has_vnet_hdr(int fd)
{
    unsigned int features = 0;

    if (ioctl(fd, TUNGETFEATURES, &features) == -1) {
        return false;
    }

    if (!(features & IFF_VNET_HDR)) {
        return false;
    }

    return true;
}

static void prep_ifreq(struct ifreq *ifr, const char *ifname)
{
    memset(ifr, 0, sizeof(*ifr));
    snprintf(ifr->ifr_name, IFNAMSIZ, "%s", ifname);
}

static int send_fd(int c, int fd)
{
    char msgbuf[CMSG_SPACE(sizeof(fd))];
    struct msghdr msg = {
        .msg_control = msgbuf,
        .msg_controllen = sizeof(msgbuf),
    };
    struct cmsghdr *cmsg;
    struct iovec iov;
    char req[1] = { 0x00 };

    cmsg = CMSG_FIRSTHDR(&msg);
    cmsg->cmsg_level = SOL_SOCKET;
    cmsg->cmsg_type = SCM_RIGHTS;
    cmsg->cmsg_len = CMSG_LEN(sizeof(fd));
    msg.msg_controllen = cmsg->cmsg_len;

    iov.iov_base = req;
    iov.iov_len = sizeof(req);

    msg.msg_iov = &iov;
    msg.msg_iovlen = 1;
    memcpy(CMSG_DATA(cmsg), &fd, sizeof(fd));

    return sendmsg(c, &msg, 0);
}

#ifdef CONFIG_LIBCAP
static int drop_privileges(void)
{
    /* clear all capabilities */
    capng_clear(CAPNG_SELECT_BOTH);

    if (capng_update(CAPNG_ADD, CAPNG_EFFECTIVE | CAPNG_PERMITTED,
                     CAP_NET_ADMIN) < 0) {
        return -1;
    }

    /* change to calling user's real uid and gid, retaining supplemental
     * groups and CAP_NET_ADMIN */
    if (capng_change_id(getuid(), getgid(), CAPNG_CLEAR_BOUNDING)) {
        return -1;
    }

    return 0;
}
#endif

int main(int argc, char **argv)
{
    struct ifreq ifr;
#ifndef SIOCBRADDIF
    unsigned long ifargs[4];
#endif
    int ifindex;
    int fd, ctlfd, unixfd = -1;
    int use_vnet = 0;
    int mtu;
    const char *bridge = NULL;
    char iface[IFNAMSIZ];
    int index;
    ACLRule *acl_rule;
    ACLList acl_list;
    int access_allowed, access_denied;
    int ret = EXIT_SUCCESS;

#ifdef CONFIG_LIBCAP
    /* if we're run from an suid binary, immediately drop privileges preserving
     * cap_net_admin */
    if (geteuid() == 0 && getuid() != geteuid()) {
        if (drop_privileges() == -1) {
            fprintf(stderr, "failed to drop privileges\n");
            return 1;
        }
    }
#endif

    /* parse arguments */
    for (index = 1; index < argc; index++) {
        if (strcmp(argv[index], "--use-vnet") == 0) {
            use_vnet = 1;
        } else if (strncmp(argv[index], "--br=", 5) == 0) {
            bridge = &argv[index][5];
        } else if (strncmp(argv[index], "--fd=", 5) == 0) {
            unixfd = atoi(&argv[index][5]);
        } else {
            usage();
            return EXIT_FAILURE;
        }
    }

    if (bridge == NULL || unixfd == -1) {
        usage();
        return EXIT_FAILURE;
    }

    /* parse default acl file */
    QSIMPLEQ_INIT(&acl_list);
    if (parse_acl_file(DEFAULT_ACL_FILE, &acl_list) == -1) {
        fprintf(stderr, "failed to parse default acl file `%s'\n",
                DEFAULT_ACL_FILE);
        ret = EXIT_FAILURE;
        goto cleanup;
    }

    /* validate bridge against acl -- default policy is to deny
     * according acl policy if we have a deny and allow both
     * then deny should always win over allow
     */
    access_allowed = 0;
    access_denied = 0;
    QSIMPLEQ_FOREACH(acl_rule, &acl_list, entry) {
        switch (acl_rule->type) {
        case ACL_ALLOW_ALL:
            access_allowed = 1;
            break;
        case ACL_ALLOW:
            if (strcmp(bridge, acl_rule->iface) == 0) {
                access_allowed = 1;
            }
            break;
        case ACL_DENY_ALL:
            access_denied = 1;
            break;
        case ACL_DENY:
            if (strcmp(bridge, acl_rule->iface) == 0) {
                access_denied = 1;
            }
            break;
        }
    }

    if ((access_allowed == 0) || (access_denied == 1)) {
        fprintf(stderr, "access denied by acl file\n");
        ret = EXIT_FAILURE;
        goto cleanup;
    }

    /* open a socket to use to control the network interfaces */
    ctlfd = socket(AF_INET, SOCK_STREAM, 0);
    if (ctlfd == -1) {
        fprintf(stderr, "failed to open control socket: %s\n", strerror(errno));
        ret = EXIT_FAILURE;
        goto cleanup;
    }

    /* open the tap device */
    fd = open("/dev/net/tun", O_RDWR);
    if (fd == -1) {
        fprintf(stderr, "failed to open /dev/net/tun: %s\n", strerror(errno));
        ret = EXIT_FAILURE;
        goto cleanup;
    }

    /* request a tap device, disable PI, and add vnet header support if
     * requested and it's available. */
    prep_ifreq(&ifr, "tap%d");
    ifr.ifr_flags = IFF_TAP|IFF_NO_PI;
    if (use_vnet && has_vnet_hdr(fd)) {
        ifr.ifr_flags |= IFF_VNET_HDR;
    }

    if (ioctl(fd, TUNSETIFF, &ifr) == -1) {
        fprintf(stderr, "failed to create tun device: %s\n", strerror(errno));
        ret = EXIT_FAILURE;
        goto cleanup;
    }

    /* save tap device name */
    snprintf(iface, sizeof(iface), "%s", ifr.ifr_name);

    /* get the mtu of the bridge */
    prep_ifreq(&ifr, bridge);
    if (ioctl(ctlfd, SIOCGIFMTU, &ifr) == -1) {
        fprintf(stderr, "failed to get mtu of bridge `%s': %s\n",
                bridge, strerror(errno));
        ret = EXIT_FAILURE;
        goto cleanup;
    }

    /* save mtu */
    mtu = ifr.ifr_mtu;

    /* set the mtu of the interface based on the bridge */
    prep_ifreq(&ifr, iface);
    ifr.ifr_mtu = mtu;
    if (ioctl(ctlfd, SIOCSIFMTU, &ifr) == -1) {
        fprintf(stderr, "failed to set mtu of device `%s' to %d: %s\n",
                iface, mtu, strerror(errno));
        ret = EXIT_FAILURE;
        goto cleanup;
    }

    /* add the interface to the bridge */
    prep_ifreq(&ifr, bridge);
    ifindex = if_nametoindex(iface);
#ifndef SIOCBRADDIF
    ifargs[0] = BRCTL_ADD_IF;
    ifargs[1] = ifindex;
    ifargs[2] = 0;
    ifargs[3] = 0;
    ifr.ifr_data = (void *)ifargs;
    ret = ioctl(ctlfd, SIOCDEVPRIVATE, &ifr);
#else
    ifr.ifr_ifindex = ifindex;
    ret = ioctl(ctlfd, SIOCBRADDIF, &ifr);
#endif
    if (ret == -1) {
        fprintf(stderr, "failed to add interface `%s' to bridge `%s': %s\n",
                iface, bridge, strerror(errno));
        ret = EXIT_FAILURE;
        goto cleanup;
    }

    /* bring the interface up */
    prep_ifreq(&ifr, iface);
    if (ioctl(ctlfd, SIOCGIFFLAGS, &ifr) == -1) {
        fprintf(stderr, "failed to get interface flags for `%s': %s\n",
                iface, strerror(errno));
        ret = EXIT_FAILURE;
        goto cleanup;
    }

    ifr.ifr_flags |= IFF_UP;
    if (ioctl(ctlfd, SIOCSIFFLAGS, &ifr) == -1) {
        fprintf(stderr, "failed to bring up interface `%s': %s\n",
                iface, strerror(errno));
        ret = EXIT_FAILURE;
        goto cleanup;
    }

    /* write fd to the domain socket */
    if (send_fd(unixfd, fd) == -1) {
        fprintf(stderr, "failed to write fd to unix socket: %s\n",
                strerror(errno));
        ret = EXIT_FAILURE;
        goto cleanup;
    }

    /* ... */

    /* profit! */

cleanup:

    while ((acl_rule = QSIMPLEQ_FIRST(&acl_list)) != NULL) {
        QSIMPLEQ_REMOVE_HEAD(&acl_list, entry);
        g_free(acl_rule);
    }

    return ret;
}
Commit	Line	Data
7b93fadf CB	1	/*
	2	* QEMU Bridge Helper
	3	*
	4	* Copyright IBM, Corp. 2011
	5	*
	6	* Authors:
	7	* Anthony Liguori <aliguori@us.ibm.com>
	8	* Richa Marwaha <rmarwah@linux.vnet.ibm.com>
	9	* Corey Bryant <coreyb@linux.vnet.ibm.com>
	10	*
	11	* This work is licensed under the terms of the GNU GPL, version 2. See
	12	* the COPYING file in the top-level directory.
	13	*
	14	*/
	15
	16	#include "config-host.h"
	17
	18	#include <stdio.h>
	19	#include <errno.h>
	20	#include <fcntl.h>
	21	#include <unistd.h>
	22	#include <string.h>
	23	#include <stdlib.h>
	24	#include <stdbool.h>
	25	#include <ctype.h>
bdef79a2	26	#include <glib.h>
7b93fadf CB	27
	28	#include <sys/types.h>
	29	#include <sys/ioctl.h>
	30	#include <sys/socket.h>
	31	#include <sys/un.h>
	32	#include <sys/prctl.h>
	33
	34	#include <net/if.h>
	35
	36	#include <linux/sockios.h>
	37
34309d2b CB	38	#ifndef SIOCBRADDIF
	39	#include <linux/if_bridge.h>
	40	#endif
	41
1de7afc9	42	#include "qemu/queue.h"
bdef79a2	43
7b93fadf CB	44	#include "net/tap-linux.h"
7b93fadf CB	45
47e98658 CB	46	#ifdef CONFIG_LIBCAP
	47	#include <cap-ng.h>
	48	#endif
	49
bdef79a2 CB	50	#define DEFAULT_ACL_FILE CONFIG_QEMU_CONFDIR "/bridge.conf"
	51
	52	enum {
	53	ACL_ALLOW = 0,
	54	ACL_ALLOW_ALL,
	55	ACL_DENY,
	56	ACL_DENY_ALL,
	57	};
	58
	59	typedef struct ACLRule {
	60	int type;
	61	char iface[IFNAMSIZ];
	62	QSIMPLEQ_ENTRY(ACLRule) entry;
	63	} ACLRule;
	64
	65	typedef QSIMPLEQ_HEAD(ACLList, ACLRule) ACLList;
	66
7b93fadf CB	67	static void usage(void)
	68	{
	69	fprintf(stderr,
	70	"Usage: qemu-bridge-helper [--use-vnet] --br=bridge --fd=unixfd\n");
	71	}
	72
bdef79a2 CB	73	static int parse_acl_file(const char filename, ACLList acl_list)
	74	{
	75	FILE *f;
	76	char line[4096];
	77	ACLRule *acl_rule;
	78
	79	f = fopen(filename, "r");
	80	if (f == NULL) {
	81	return -1;
	82	}
	83
	84	while (fgets(line, sizeof(line), f) != NULL) {
	85	char *ptr = line;
	86	char cmd, arg, *argend;
	87
	88	while (isspace(*ptr)) {
	89	ptr++;
	90	}
	91
	92	/* skip comments and empty lines */
	93	if (ptr == '#' \|\| ptr == 0) {
	94	continue;
	95	}
	96
	97	cmd = ptr;
	98	arg = strchr(cmd, ' ');
	99	if (arg == NULL) {
	100	arg = strchr(cmd, '\t');
	101	}
	102
	103	if (arg == NULL) {
	104	fprintf(stderr, "Invalid config line:\n %s\n", line);
	105	fclose(f);
	106	errno = EINVAL;
	107	return -1;
	108	}
	109
	110	*arg = 0;
	111	arg++;
	112	while (isspace(*arg)) {
	113	arg++;
	114	}
	115
	116	argend = arg + strlen(arg);
	117	while (arg != argend && isspace(*(argend - 1))) {
	118	argend--;
	119	}
	120	*argend = 0;
	121
	122	if (strcmp(cmd, "deny") == 0) {
	123	acl_rule = g_malloc(sizeof(*acl_rule));
	124	if (strcmp(arg, "all") == 0) {
	125	acl_rule->type = ACL_DENY_ALL;
	126	} else {
	127	acl_rule->type = ACL_DENY;
	128	snprintf(acl_rule->iface, IFNAMSIZ, "%s", arg);
	129	}
	130	QSIMPLEQ_INSERT_TAIL(acl_list, acl_rule, entry);
	131	} else if (strcmp(cmd, "allow") == 0) {
	132	acl_rule = g_malloc(sizeof(*acl_rule));
	133	if (strcmp(arg, "all") == 0) {
	134	acl_rule->type = ACL_ALLOW_ALL;
	135	} else {
	136	acl_rule->type = ACL_ALLOW;
137	snprintf(acl_rule->iface, IFNAMSIZ, "%s", arg);
138	}
139	QSIMPLEQ_INSERT_TAIL(acl_list, acl_rule, entry);
140	} else if (strcmp(cmd, "include") == 0) {
141	/* ignore errors */
142	parse_acl_file(arg, acl_list);
143	} else {
144	fprintf(stderr, "Unknown command `%s'\n", cmd);
145	fclose(f);
146	errno = EINVAL;
147	return -1;
148	}
149	}
150
151	fclose(f);
152
153	return 0;
154	}
155
7b93fadf CB	156	static bool has_vnet_hdr(int fd)
	157	{
	158	unsigned int features = 0;
	159
	160	if (ioctl(fd, TUNGETFEATURES, &features) == -1) {
	161	return false;
	162	}
	163
	164	if (!(features & IFF_VNET_HDR)) {
	165	return false;
	166	}
	167
	168	return true;
	169	}
	170
	171	static void prep_ifreq(struct ifreq ifr, const char ifname)
	172	{
	173	memset(ifr, 0, sizeof(*ifr));
	174	snprintf(ifr->ifr_name, IFNAMSIZ, "%s", ifname);
	175	}
	176
	177	static int send_fd(int c, int fd)
	178	{
	179	char msgbuf[CMSG_SPACE(sizeof(fd))];
	180	struct msghdr msg = {
	181	.msg_control = msgbuf,
	182	.msg_controllen = sizeof(msgbuf),
	183	};
	184	struct cmsghdr *cmsg;
	185	struct iovec iov;
	186	char req[1] = { 0x00 };
	187
	188	cmsg = CMSG_FIRSTHDR(&msg);
	189	cmsg->cmsg_level = SOL_SOCKET;
	190	cmsg->cmsg_type = SCM_RIGHTS;
	191	cmsg->cmsg_len = CMSG_LEN(sizeof(fd));
	192	msg.msg_controllen = cmsg->cmsg_len;
	193
	194	iov.iov_base = req;
	195	iov.iov_len = sizeof(req);
	196
	197	msg.msg_iov = &iov;
	198	msg.msg_iovlen = 1;
	199	memcpy(CMSG_DATA(cmsg), &fd, sizeof(fd));
	200
	201	return sendmsg(c, &msg, 0);
	202	}
	203
47e98658 CB	204	#ifdef CONFIG_LIBCAP
	205	static int drop_privileges(void)
	206	{
	207	/* clear all capabilities */
	208	capng_clear(CAPNG_SELECT_BOTH);
	209
	210	if (capng_update(CAPNG_ADD, CAPNG_EFFECTIVE \| CAPNG_PERMITTED,
	211	CAP_NET_ADMIN) < 0) {
	212	return -1;
	213	}
	214
	215	/* change to calling user's real uid and gid, retaining supplemental
	216	* groups and CAP_NET_ADMIN */
	217	if (capng_change_id(getuid(), getgid(), CAPNG_CLEAR_BOUNDING)) {
	218	return -1;
	219	}
	220
	221	return 0;
	222	}
	223	#endif
	224
7b93fadf CB	225	int main(int argc, char **argv)
	226	{
	227	struct ifreq ifr;
34309d2b CB	228	#ifndef SIOCBRADDIF
	229	unsigned long ifargs[4];
	230	#endif
	231	int ifindex;
7b93fadf CB	232	int fd, ctlfd, unixfd = -1;
	233	int use_vnet = 0;
	234	int mtu;
	235	const char *bridge = NULL;
	236	char iface[IFNAMSIZ];
	237	int index;
bdef79a2 CB	238	ACLRule *acl_rule;
	239	ACLList acl_list;
	240	int access_allowed, access_denied;
7b93fadf CB	241	int ret = EXIT_SUCCESS;
7b93fadf CB	242
47e98658 CB	243	#ifdef CONFIG_LIBCAP
	244	/* if we're run from an suid binary, immediately drop privileges preserving
	245	* cap_net_admin */
	246	if (geteuid() == 0 && getuid() != geteuid()) {
	247	if (drop_privileges() == -1) {
	248	fprintf(stderr, "failed to drop privileges\n");
	249	return 1;
	250	}
	251	}
	252	#endif
	253
7b93fadf CB	254	/* parse arguments */
	255	for (index = 1; index < argc; index++) {
	256	if (strcmp(argv[index], "--use-vnet") == 0) {
	257	use_vnet = 1;
	258	} else if (strncmp(argv[index], "--br=", 5) == 0) {
	259	bridge = &argv[index][5];
	260	} else if (strncmp(argv[index], "--fd=", 5) == 0) {
	261	unixfd = atoi(&argv[index][5]);
	262	} else {
	263	usage();
	264	return EXIT_FAILURE;
	265	}
	266	}
	267
	268	if (bridge == NULL \|\| unixfd == -1) {
	269	usage();
	270	return EXIT_FAILURE;
	271	}
	272
bdef79a2 CB	273	/* parse default acl file */
	274	QSIMPLEQ_INIT(&acl_list);
	275	if (parse_acl_file(DEFAULT_ACL_FILE, &acl_list) == -1) {
	276	fprintf(stderr, "failed to parse default acl file `%s'\n",
	277	DEFAULT_ACL_FILE);
	278	ret = EXIT_FAILURE;
	279	goto cleanup;
	280	}
	281
	282	/* validate bridge against acl -- default policy is to deny
	283	* according acl policy if we have a deny and allow both
	284	* then deny should always win over allow
	285	*/
	286	access_allowed = 0;
	287	access_denied = 0;
	288	QSIMPLEQ_FOREACH(acl_rule, &acl_list, entry) {
	289	switch (acl_rule->type) {
	290	case ACL_ALLOW_ALL:
	291	access_allowed = 1;
	292	break;
	293	case ACL_ALLOW:
	294	if (strcmp(bridge, acl_rule->iface) == 0) {
	295	access_allowed = 1;
	296	}
	297	break;
	298	case ACL_DENY_ALL:
	299	access_denied = 1;
	300	break;
	301	case ACL_DENY:
	302	if (strcmp(bridge, acl_rule->iface) == 0) {
	303	access_denied = 1;
	304	}
	305	break;
	306	}
	307	}
	308
	309	if ((access_allowed == 0) \|\| (access_denied == 1)) {
	310	fprintf(stderr, "access denied by acl file\n");
	311	ret = EXIT_FAILURE;
	312	goto cleanup;
	313	}
	314
7b93fadf CB	315	/* open a socket to use to control the network interfaces */
	316	ctlfd = socket(AF_INET, SOCK_STREAM, 0);
	317	if (ctlfd == -1) {
	318	fprintf(stderr, "failed to open control socket: %s\n", strerror(errno));
	319	ret = EXIT_FAILURE;
	320	goto cleanup;
	321	}
	322
	323	/* open the tap device */
	324	fd = open("/dev/net/tun", O_RDWR);
	325	if (fd == -1) {
	326	fprintf(stderr, "failed to open /dev/net/tun: %s\n", strerror(errno));
	327	ret = EXIT_FAILURE;
	328	goto cleanup;
	329	}
	330
	331	/* request a tap device, disable PI, and add vnet header support if
	332	* requested and it's available. */
	333	prep_ifreq(&ifr, "tap%d");
	334	ifr.ifr_flags = IFF_TAP\|IFF_NO_PI;
	335	if (use_vnet && has_vnet_hdr(fd)) {
	336	ifr.ifr_flags \|= IFF_VNET_HDR;
	337	}
	338
	339	if (ioctl(fd, TUNSETIFF, &ifr) == -1) {
	340	fprintf(stderr, "failed to create tun device: %s\n", strerror(errno));
	341	ret = EXIT_FAILURE;
	342	goto cleanup;
	343	}
	344
	345	/* save tap device name */
	346	snprintf(iface, sizeof(iface), "%s", ifr.ifr_name);
	347
	348	/* get the mtu of the bridge */
	349	prep_ifreq(&ifr, bridge);
	350	if (ioctl(ctlfd, SIOCGIFMTU, &ifr) == -1) {
	351	fprintf(stderr, "failed to get mtu of bridge `%s': %s\n",
	352	bridge, strerror(errno));
	353	ret = EXIT_FAILURE;
	354	goto cleanup;
	355	}
	356
	357	/* save mtu */
	358	mtu = ifr.ifr_mtu;
	359
	360	/* set the mtu of the interface based on the bridge */
	361	prep_ifreq(&ifr, iface);
	362	ifr.ifr_mtu = mtu;
	363	if (ioctl(ctlfd, SIOCSIFMTU, &ifr) == -1) {
	364	fprintf(stderr, "failed to set mtu of device `%s' to %d: %s\n",
	365	iface, mtu, strerror(errno));
	366	ret = EXIT_FAILURE;
	367	goto cleanup;
	368	}
	369
	370	/* add the interface to the bridge */
	371	prep_ifreq(&ifr, bridge);
34309d2b CB	372	ifindex = if_nametoindex(iface);
	373	#ifndef SIOCBRADDIF
	374	ifargs[0] = BRCTL_ADD_IF;
	375	ifargs[1] = ifindex;
	376	ifargs[2] = 0;
	377	ifargs[3] = 0;
	378	ifr.ifr_data = (void *)ifargs;
	379	ret = ioctl(ctlfd, SIOCDEVPRIVATE, &ifr);
	380	#else
	381	ifr.ifr_ifindex = ifindex;
	382	ret = ioctl(ctlfd, SIOCBRADDIF, &ifr);
	383	#endif
	384	if (ret == -1) {
7b93fadf CB	385	fprintf(stderr, "failed to add interface `%s' to bridge `%s': %s\n",
	386	iface, bridge, strerror(errno));
	387	ret = EXIT_FAILURE;
	388	goto cleanup;
	389	}
	390
	391	/* bring the interface up */
	392	prep_ifreq(&ifr, iface);
	393	if (ioctl(ctlfd, SIOCGIFFLAGS, &ifr) == -1) {
	394	fprintf(stderr, "failed to get interface flags for `%s': %s\n",
	395	iface, strerror(errno));
	396	ret = EXIT_FAILURE;
	397	goto cleanup;
	398	}
	399
	400	ifr.ifr_flags \|= IFF_UP;
	401	if (ioctl(ctlfd, SIOCSIFFLAGS, &ifr) == -1) {
	402	fprintf(stderr, "failed to bring up interface `%s': %s\n",
	403	iface, strerror(errno));
	404	ret = EXIT_FAILURE;
	405	goto cleanup;
	406	}
	407
	408	/* write fd to the domain socket */
	409	if (send_fd(unixfd, fd) == -1) {
	410	fprintf(stderr, "failed to write fd to unix socket: %s\n",
	411	strerror(errno));
	412	ret = EXIT_FAILURE;
	413	goto cleanup;
	414	}
	415
	416	/* ... */
	417
	418	/* profit! */
	419
	420	cleanup:
	421
bdef79a2 CB	422	while ((acl_rule = QSIMPLEQ_FIRST(&acl_list)) != NULL) {
	423	QSIMPLEQ_REMOVE_HEAD(&acl_list, entry);
	424	g_free(acl_rule);
	425	}
	426
7b93fadf CB	427	return ret;
7b93fadf CB	428	}