[mirror_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 "qemu/osdep.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 = -1, ctlfd = -1, 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;
    }

    /* Linux uses the lowest enslaved MAC address as the MAC address of
     * the bridge.  Set MAC address to a high value so that it doesn't
     * affect the MAC address of the bridge.
     */
    if (ioctl(ctlfd, SIOCGIFHWADDR, &ifr) < 0) {
        fprintf(stderr, "failed to get MAC address of device `%s': %s\n",
                iface, strerror(errno));
        ret = EXIT_FAILURE;
        goto cleanup;
    }
    ifr.ifr_hwaddr.sa_data[0] = 0xFE;
    if (ioctl(ctlfd, SIOCSIFHWADDR, &ifr) < 0) {
        fprintf(stderr, "failed to set MAC address of device `%s': %s\n",
                iface, 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:
    if (fd >= 0) {
        close(fd);
    }
    if (ctlfd >= 0) {
        close(ctlfd);
    }
    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
d38ea87a	16	#include "qemu/osdep.h"
7b93fadf	17
7b93fadf	18
7b93fadf CB	19	#include <sys/ioctl.h>
	20	#include <sys/socket.h>
	21	#include <sys/un.h>
	22	#include <sys/prctl.h>
	23
	24	#include <net/if.h>
	25
	26	#include <linux/sockios.h>
	27
34309d2b CB	28	#ifndef SIOCBRADDIF
	29	#include <linux/if_bridge.h>
	30	#endif
	31
1de7afc9	32	#include "qemu/queue.h"
bdef79a2	33
7b93fadf CB	34	#include "net/tap-linux.h"
7b93fadf CB	35
47e98658 CB	36	#ifdef CONFIG_LIBCAP
	37	#include <cap-ng.h>
	38	#endif
	39
bdef79a2 CB	40	#define DEFAULT_ACL_FILE CONFIG_QEMU_CONFDIR "/bridge.conf"
	41
	42	enum {
	43	ACL_ALLOW = 0,
	44	ACL_ALLOW_ALL,
	45	ACL_DENY,
	46	ACL_DENY_ALL,
	47	};
	48
	49	typedef struct ACLRule {
	50	int type;
	51	char iface[IFNAMSIZ];
	52	QSIMPLEQ_ENTRY(ACLRule) entry;
	53	} ACLRule;
	54
	55	typedef QSIMPLEQ_HEAD(ACLList, ACLRule) ACLList;
	56
7b93fadf CB	57	static void usage(void)
	58	{
	59	fprintf(stderr,
	60	"Usage: qemu-bridge-helper [--use-vnet] --br=bridge --fd=unixfd\n");
	61	}
	62
bdef79a2 CB	63	static int parse_acl_file(const char filename, ACLList acl_list)
	64	{
	65	FILE *f;
	66	char line[4096];
	67	ACLRule *acl_rule;
	68
	69	f = fopen(filename, "r");
	70	if (f == NULL) {
	71	return -1;
	72	}
	73
	74	while (fgets(line, sizeof(line), f) != NULL) {
	75	char *ptr = line;
	76	char cmd, arg, *argend;
	77
	78	while (isspace(*ptr)) {
	79	ptr++;
	80	}
	81
	82	/* skip comments and empty lines */
	83	if (ptr == '#' \|\| ptr == 0) {
	84	continue;
	85	}
	86
	87	cmd = ptr;
	88	arg = strchr(cmd, ' ');
	89	if (arg == NULL) {
	90	arg = strchr(cmd, '\t');
	91	}
	92
	93	if (arg == NULL) {
	94	fprintf(stderr, "Invalid config line:\n %s\n", line);
	95	fclose(f);
	96	errno = EINVAL;
	97	return -1;
	98	}
	99
	100	*arg = 0;
	101	arg++;
	102	while (isspace(*arg)) {
	103	arg++;
	104	}
	105
	106	argend = arg + strlen(arg);
	107	while (arg != argend && isspace(*(argend - 1))) {
	108	argend--;
	109	}
	110	*argend = 0;
	111
	112	if (strcmp(cmd, "deny") == 0) {
	113	acl_rule = g_malloc(sizeof(*acl_rule));
	114	if (strcmp(arg, "all") == 0) {
	115	acl_rule->type = ACL_DENY_ALL;
	116	} else {
	117	acl_rule->type = ACL_DENY;
	118	snprintf(acl_rule->iface, IFNAMSIZ, "%s", arg);
	119	}
	120	QSIMPLEQ_INSERT_TAIL(acl_list, acl_rule, entry);
	121	} else if (strcmp(cmd, "allow") == 0) {
	122	acl_rule = g_malloc(sizeof(*acl_rule));
	123	if (strcmp(arg, "all") == 0) {
	124	acl_rule->type = ACL_ALLOW_ALL;
	125	} else {
	126	acl_rule->type = ACL_ALLOW;
127	snprintf(acl_rule->iface, IFNAMSIZ, "%s", arg);
128	}
129	QSIMPLEQ_INSERT_TAIL(acl_list, acl_rule, entry);
130	} else if (strcmp(cmd, "include") == 0) {
131	/* ignore errors */
132	parse_acl_file(arg, acl_list);
133	} else {
134	fprintf(stderr, "Unknown command `%s'\n", cmd);
135	fclose(f);
136	errno = EINVAL;
137	return -1;
138	}
139	}
140
141	fclose(f);
142
143	return 0;
144	}
145
7b93fadf CB	146	static bool has_vnet_hdr(int fd)
	147	{
	148	unsigned int features = 0;
	149
	150	if (ioctl(fd, TUNGETFEATURES, &features) == -1) {
	151	return false;
	152	}
	153
	154	if (!(features & IFF_VNET_HDR)) {
	155	return false;
	156	}
	157
	158	return true;
	159	}
	160
	161	static void prep_ifreq(struct ifreq ifr, const char ifname)
	162	{
	163	memset(ifr, 0, sizeof(*ifr));
	164	snprintf(ifr->ifr_name, IFNAMSIZ, "%s", ifname);
	165	}
	166
	167	static int send_fd(int c, int fd)
	168	{
	169	char msgbuf[CMSG_SPACE(sizeof(fd))];
	170	struct msghdr msg = {
	171	.msg_control = msgbuf,
	172	.msg_controllen = sizeof(msgbuf),
	173	};
	174	struct cmsghdr *cmsg;
	175	struct iovec iov;
	176	char req[1] = { 0x00 };
	177
	178	cmsg = CMSG_FIRSTHDR(&msg);
	179	cmsg->cmsg_level = SOL_SOCKET;
	180	cmsg->cmsg_type = SCM_RIGHTS;
	181	cmsg->cmsg_len = CMSG_LEN(sizeof(fd));
	182	msg.msg_controllen = cmsg->cmsg_len;
	183
	184	iov.iov_base = req;
	185	iov.iov_len = sizeof(req);
	186
	187	msg.msg_iov = &iov;
	188	msg.msg_iovlen = 1;
	189	memcpy(CMSG_DATA(cmsg), &fd, sizeof(fd));
	190
	191	return sendmsg(c, &msg, 0);
	192	}
	193
47e98658 CB	194	#ifdef CONFIG_LIBCAP
	195	static int drop_privileges(void)
	196	{
	197	/* clear all capabilities */
	198	capng_clear(CAPNG_SELECT_BOTH);
	199
	200	if (capng_update(CAPNG_ADD, CAPNG_EFFECTIVE \| CAPNG_PERMITTED,
	201	CAP_NET_ADMIN) < 0) {
	202	return -1;
	203	}
	204
	205	/* change to calling user's real uid and gid, retaining supplemental
	206	* groups and CAP_NET_ADMIN */
	207	if (capng_change_id(getuid(), getgid(), CAPNG_CLEAR_BOUNDING)) {
	208	return -1;
	209	}
	210
	211	return 0;
	212	}
	213	#endif
	214
7b93fadf CB	215	int main(int argc, char **argv)
	216	{
	217	struct ifreq ifr;
34309d2b CB	218	#ifndef SIOCBRADDIF
	219	unsigned long ifargs[4];
	220	#endif
	221	int ifindex;
eb3f45c5	222	int fd = -1, ctlfd = -1, unixfd = -1;
7b93fadf CB	223	int use_vnet = 0;
	224	int mtu;
	225	const char *bridge = NULL;
	226	char iface[IFNAMSIZ];
	227	int index;
bdef79a2 CB	228	ACLRule *acl_rule;
	229	ACLList acl_list;
	230	int access_allowed, access_denied;
7b93fadf CB	231	int ret = EXIT_SUCCESS;
7b93fadf CB	232
47e98658 CB	233	#ifdef CONFIG_LIBCAP
	234	/* if we're run from an suid binary, immediately drop privileges preserving
	235	* cap_net_admin */
	236	if (geteuid() == 0 && getuid() != geteuid()) {
	237	if (drop_privileges() == -1) {
	238	fprintf(stderr, "failed to drop privileges\n");
	239	return 1;
	240	}
	241	}
	242	#endif
	243
7b93fadf CB	244	/* parse arguments */
	245	for (index = 1; index < argc; index++) {
	246	if (strcmp(argv[index], "--use-vnet") == 0) {
	247	use_vnet = 1;
	248	} else if (strncmp(argv[index], "--br=", 5) == 0) {
	249	bridge = &argv[index][5];
	250	} else if (strncmp(argv[index], "--fd=", 5) == 0) {
	251	unixfd = atoi(&argv[index][5]);
	252	} else {
	253	usage();
	254	return EXIT_FAILURE;
	255	}
	256	}
	257
	258	if (bridge == NULL \|\| unixfd == -1) {
	259	usage();
	260	return EXIT_FAILURE;
	261	}
	262
bdef79a2 CB	263	/* parse default acl file */
	264	QSIMPLEQ_INIT(&acl_list);
	265	if (parse_acl_file(DEFAULT_ACL_FILE, &acl_list) == -1) {
	266	fprintf(stderr, "failed to parse default acl file `%s'\n",
	267	DEFAULT_ACL_FILE);
	268	ret = EXIT_FAILURE;
	269	goto cleanup;
	270	}
	271
	272	/* validate bridge against acl -- default policy is to deny
	273	* according acl policy if we have a deny and allow both
	274	* then deny should always win over allow
	275	*/
	276	access_allowed = 0;
	277	access_denied = 0;
	278	QSIMPLEQ_FOREACH(acl_rule, &acl_list, entry) {
	279	switch (acl_rule->type) {
	280	case ACL_ALLOW_ALL:
	281	access_allowed = 1;
	282	break;
	283	case ACL_ALLOW:
	284	if (strcmp(bridge, acl_rule->iface) == 0) {
	285	access_allowed = 1;
	286	}
	287	break;
	288	case ACL_DENY_ALL:
	289	access_denied = 1;
	290	break;
	291	case ACL_DENY:
	292	if (strcmp(bridge, acl_rule->iface) == 0) {
	293	access_denied = 1;
	294	}
	295	break;
	296	}
	297	}
	298
	299	if ((access_allowed == 0) \|\| (access_denied == 1)) {
	300	fprintf(stderr, "access denied by acl file\n");
	301	ret = EXIT_FAILURE;
	302	goto cleanup;
	303	}
	304
7b93fadf CB	305	/* open a socket to use to control the network interfaces */
	306	ctlfd = socket(AF_INET, SOCK_STREAM, 0);
	307	if (ctlfd == -1) {
	308	fprintf(stderr, "failed to open control socket: %s\n", strerror(errno));
	309	ret = EXIT_FAILURE;
	310	goto cleanup;
	311	}
	312
	313	/* open the tap device */
	314	fd = open("/dev/net/tun", O_RDWR);
	315	if (fd == -1) {
	316	fprintf(stderr, "failed to open /dev/net/tun: %s\n", strerror(errno));
	317	ret = EXIT_FAILURE;
	318	goto cleanup;
	319	}
	320
	321	/* request a tap device, disable PI, and add vnet header support if
	322	* requested and it's available. */
	323	prep_ifreq(&ifr, "tap%d");
	324	ifr.ifr_flags = IFF_TAP\|IFF_NO_PI;
	325	if (use_vnet && has_vnet_hdr(fd)) {
	326	ifr.ifr_flags \|= IFF_VNET_HDR;
	327	}
	328
	329	if (ioctl(fd, TUNSETIFF, &ifr) == -1) {
	330	fprintf(stderr, "failed to create tun device: %s\n", strerror(errno));
	331	ret = EXIT_FAILURE;
	332	goto cleanup;
	333	}
	334
	335	/* save tap device name */
	336	snprintf(iface, sizeof(iface), "%s", ifr.ifr_name);
	337
	338	/* get the mtu of the bridge */
	339	prep_ifreq(&ifr, bridge);
	340	if (ioctl(ctlfd, SIOCGIFMTU, &ifr) == -1) {
	341	fprintf(stderr, "failed to get mtu of bridge `%s': %s\n",
	342	bridge, strerror(errno));
	343	ret = EXIT_FAILURE;
	344	goto cleanup;
	345	}
	346
	347	/* save mtu */
	348	mtu = ifr.ifr_mtu;
	349
	350	/* set the mtu of the interface based on the bridge */
	351	prep_ifreq(&ifr, iface);
	352	ifr.ifr_mtu = mtu;
	353	if (ioctl(ctlfd, SIOCSIFMTU, &ifr) == -1) {
	354	fprintf(stderr, "failed to set mtu of device `%s' to %d: %s\n",
	355	iface, mtu, strerror(errno));
	356	ret = EXIT_FAILURE;
	357	goto cleanup;
	358	}
	359
226ecabf PB	360	/* Linux uses the lowest enslaved MAC address as the MAC address of
	361	* the bridge. Set MAC address to a high value so that it doesn't
	362	* affect the MAC address of the bridge.
	363	*/
	364	if (ioctl(ctlfd, SIOCGIFHWADDR, &ifr) < 0) {
	365	fprintf(stderr, "failed to get MAC address of device `%s': %s\n",
	366	iface, strerror(errno));
	367	ret = EXIT_FAILURE;
	368	goto cleanup;
	369	}
	370	ifr.ifr_hwaddr.sa_data[0] = 0xFE;
	371	if (ioctl(ctlfd, SIOCSIFHWADDR, &ifr) < 0) {
	372	fprintf(stderr, "failed to set MAC address of device `%s': %s\n",
	373	iface, strerror(errno));
	374	ret = EXIT_FAILURE;
	375	goto cleanup;
	376	}
	377
7b93fadf CB	378	/* add the interface to the bridge */
7b93fadf CB	379	prep_ifreq(&ifr, bridge);
34309d2b CB	380	ifindex = if_nametoindex(iface);
	381	#ifndef SIOCBRADDIF
	382	ifargs[0] = BRCTL_ADD_IF;
	383	ifargs[1] = ifindex;
	384	ifargs[2] = 0;
	385	ifargs[3] = 0;
	386	ifr.ifr_data = (void *)ifargs;
	387	ret = ioctl(ctlfd, SIOCDEVPRIVATE, &ifr);
	388	#else
	389	ifr.ifr_ifindex = ifindex;
	390	ret = ioctl(ctlfd, SIOCBRADDIF, &ifr);
	391	#endif
	392	if (ret == -1) {
7b93fadf CB	393	fprintf(stderr, "failed to add interface `%s' to bridge `%s': %s\n",
	394	iface, bridge, strerror(errno));
	395	ret = EXIT_FAILURE;
	396	goto cleanup;
	397	}
	398
	399	/* bring the interface up */
	400	prep_ifreq(&ifr, iface);
	401	if (ioctl(ctlfd, SIOCGIFFLAGS, &ifr) == -1) {
	402	fprintf(stderr, "failed to get interface flags for `%s': %s\n",
	403	iface, strerror(errno));
	404	ret = EXIT_FAILURE;
	405	goto cleanup;
	406	}
	407
	408	ifr.ifr_flags \|= IFF_UP;
	409	if (ioctl(ctlfd, SIOCSIFFLAGS, &ifr) == -1) {
	410	fprintf(stderr, "failed to bring up interface `%s': %s\n",
	411	iface, strerror(errno));
	412	ret = EXIT_FAILURE;
	413	goto cleanup;
	414	}
	415
	416	/* write fd to the domain socket */
	417	if (send_fd(unixfd, fd) == -1) {
	418	fprintf(stderr, "failed to write fd to unix socket: %s\n",
	419	strerror(errno));
	420	ret = EXIT_FAILURE;
	421	goto cleanup;
	422	}
	423
	424	/* ... */
	425
	426	/* profit! */
	427
	428	cleanup:
eb3f45c5 GA	429	if (fd >= 0) {
	430	close(fd);
	431	}
	432	if (ctlfd >= 0) {
	433	close(ctlfd);
	434	}
bdef79a2 CB	435	while ((acl_rule = QSIMPLEQ_FIRST(&acl_list)) != NULL) {
	436	QSIMPLEQ_REMOVE_HEAD(&acl_list, entry);
	437	g_free(acl_rule);
	438	}
	439
7b93fadf CB	440	return ret;
7b93fadf CB	441	}