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

/*
 * QEMU Bridge Helper
 *
 * Copyright IBM, Corp. 2011
 *
 * Authors:
 * Anthony Liguori   <[email protected]>
 * Richa Marwaha     <[email protected]>
 * Corey Bryant      <[email protected]>
 *
 * This work is licensed under the terms of the GNU GPL, version 2.  See
 * the COPYING file in the top-level directory.
 */

/*
 * Known shortcomings:
 * - There is no manual page
 * - The syntax of the ACL file is not documented anywhere
 * - parse_acl_file() doesn't report fopen() failure properly, fails
 *   to check ferror() after fgets() failure, arbitrarily truncates
 *   long lines, handles whitespace inconsistently, error messages
 *   don't point to the offending file and line, errors in included
 *   files are reported, but otherwise ignored, ...
 */

#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 (g_ascii_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);
            goto err;
        }

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

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

        if (!g_str_equal(cmd, "include") && strlen(arg) >= IFNAMSIZ) {
            fprintf(stderr, "name `%s' too long: %zu\n", arg, strlen(arg));
            goto err;
        }

        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);
            goto err;
        }
    }

    fclose(f);
    return 0;

err:
    fclose(f);
    errno = EINVAL;
    return -1;

}

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;
    }
    if (strlen(bridge) >= IFNAMSIZ) {
        fprintf(stderr, "name `%s' too long: %zu\n", bridge, strlen(bridge));
        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 <[email protected]>
	8	* Richa Marwaha <[email protected]>
	9	* Corey Bryant <[email protected]>
	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.
436e3530 MA	13	*/
	14
	15	/*
	16	* Known shortcomings:
	17	* - There is no manual page
	18	* - The syntax of the ACL file is not documented anywhere
	19	* - parse_acl_file() doesn't report fopen() failure properly, fails
	20	* to check ferror() after fgets() failure, arbitrarily truncates
	21	* long lines, handles whitespace inconsistently, error messages
	22	* don't point to the offending file and line, errors in included
	23	* files are reported, but otherwise ignored, ...
7b93fadf CB	24	*/
7b93fadf CB	25
d38ea87a	26	#include "qemu/osdep.h"
7b93fadf	27
7b93fadf	28
7b93fadf CB	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
b8c3511d	88	while (g_ascii_isspace(*ptr)) {
bdef79a2 CB	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);
3283dde4	105	goto err;
bdef79a2 CB	106	}
	107
	108	*arg = 0;
	109	arg++;
b8c3511d	110	while (g_ascii_isspace(*arg)) {
bdef79a2 CB	111	arg++;
	112	}
	113
	114	argend = arg + strlen(arg);
b8c3511d	115	while (arg != argend && g_ascii_isspace(*(argend - 1))) {
bdef79a2 CB	116	argend--;
	117	}
	118	*argend = 0;
	119
6f5d8671 PP	120	if (!g_str_equal(cmd, "include") && strlen(arg) >= IFNAMSIZ) {
6f5d8671 PP	121	fprintf(stderr, "name `%s' too long: %zu\n", arg, strlen(arg));
3283dde4	122	goto err;
6f5d8671 PP	123	}
6f5d8671 PP	124
bdef79a2 CB	125	if (strcmp(cmd, "deny") == 0) {
	126	acl_rule = g_malloc(sizeof(*acl_rule));
	127	if (strcmp(arg, "all") == 0) {
	128	acl_rule->type = ACL_DENY_ALL;
	129	} else {
	130	acl_rule->type = ACL_DENY;
	131	snprintf(acl_rule->iface, IFNAMSIZ, "%s", arg);
	132	}
	133	QSIMPLEQ_INSERT_TAIL(acl_list, acl_rule, entry);
	134	} else if (strcmp(cmd, "allow") == 0) {
	135	acl_rule = g_malloc(sizeof(*acl_rule));
	136	if (strcmp(arg, "all") == 0) {
	137	acl_rule->type = ACL_ALLOW_ALL;
	138	} else {
	139	acl_rule->type = ACL_ALLOW;
	140	snprintf(acl_rule->iface, IFNAMSIZ, "%s", arg);
	141	}
	142	QSIMPLEQ_INSERT_TAIL(acl_list, acl_rule, entry);
	143	} else if (strcmp(cmd, "include") == 0) {
	144	/* ignore errors */
	145	parse_acl_file(arg, acl_list);
	146	} else {
	147	fprintf(stderr, "Unknown command `%s'\n", cmd);
3283dde4	148	goto err;
bdef79a2 CB	149	}
	150	}
	151
	152	fclose(f);
bdef79a2	153	return 0;
3283dde4 PP	154
	155	err:
	156	fclose(f);
	157	errno = EINVAL;
	158	return -1;
	159
bdef79a2 CB	160	}
bdef79a2 CB	161
7b93fadf CB	162	static bool has_vnet_hdr(int fd)
	163	{
	164	unsigned int features = 0;
	165
	166	if (ioctl(fd, TUNGETFEATURES, &features) == -1) {
	167	return false;
	168	}
	169
	170	if (!(features & IFF_VNET_HDR)) {
	171	return false;
	172	}
	173
	174	return true;
	175	}
	176
	177	static void prep_ifreq(struct ifreq ifr, const char ifname)
	178	{
	179	memset(ifr, 0, sizeof(*ifr));
	180	snprintf(ifr->ifr_name, IFNAMSIZ, "%s", ifname);
	181	}
	182
	183	static int send_fd(int c, int fd)
	184	{
	185	char msgbuf[CMSG_SPACE(sizeof(fd))];
	186	struct msghdr msg = {
	187	.msg_control = msgbuf,
	188	.msg_controllen = sizeof(msgbuf),
	189	};
	190	struct cmsghdr *cmsg;
	191	struct iovec iov;
	192	char req[1] = { 0x00 };
	193
	194	cmsg = CMSG_FIRSTHDR(&msg);
	195	cmsg->cmsg_level = SOL_SOCKET;
	196	cmsg->cmsg_type = SCM_RIGHTS;
	197	cmsg->cmsg_len = CMSG_LEN(sizeof(fd));
	198	msg.msg_controllen = cmsg->cmsg_len;
	199
	200	iov.iov_base = req;
	201	iov.iov_len = sizeof(req);
	202
	203	msg.msg_iov = &iov;
	204	msg.msg_iovlen = 1;
	205	memcpy(CMSG_DATA(cmsg), &fd, sizeof(fd));
	206
	207	return sendmsg(c, &msg, 0);
	208	}
	209
47e98658 CB	210	#ifdef CONFIG_LIBCAP
	211	static int drop_privileges(void)
	212	{
	213	/* clear all capabilities */
	214	capng_clear(CAPNG_SELECT_BOTH);
	215
	216	if (capng_update(CAPNG_ADD, CAPNG_EFFECTIVE \| CAPNG_PERMITTED,
	217	CAP_NET_ADMIN) < 0) {
	218	return -1;
	219	}
	220
	221	/* change to calling user's real uid and gid, retaining supplemental
	222	* groups and CAP_NET_ADMIN */
	223	if (capng_change_id(getuid(), getgid(), CAPNG_CLEAR_BOUNDING)) {
	224	return -1;
	225	}
	226
	227	return 0;
	228	}
	229	#endif
	230
7b93fadf CB	231	int main(int argc, char **argv)
	232	{
	233	struct ifreq ifr;
34309d2b CB	234	#ifndef SIOCBRADDIF
	235	unsigned long ifargs[4];
	236	#endif
	237	int ifindex;
eb3f45c5	238	int fd = -1, ctlfd = -1, unixfd = -1;
7b93fadf CB	239	int use_vnet = 0;
	240	int mtu;
	241	const char *bridge = NULL;
	242	char iface[IFNAMSIZ];
	243	int index;
bdef79a2 CB	244	ACLRule *acl_rule;
	245	ACLList acl_list;
	246	int access_allowed, access_denied;
7b93fadf CB	247	int ret = EXIT_SUCCESS;
7b93fadf CB	248
47e98658 CB	249	#ifdef CONFIG_LIBCAP
	250	/* if we're run from an suid binary, immediately drop privileges preserving
	251	* cap_net_admin */
	252	if (geteuid() == 0 && getuid() != geteuid()) {
	253	if (drop_privileges() == -1) {
	254	fprintf(stderr, "failed to drop privileges\n");
	255	return 1;
	256	}
	257	}
	258	#endif
	259
7b93fadf CB	260	/* parse arguments */
	261	for (index = 1; index < argc; index++) {
	262	if (strcmp(argv[index], "--use-vnet") == 0) {
	263	use_vnet = 1;
	264	} else if (strncmp(argv[index], "--br=", 5) == 0) {
	265	bridge = &argv[index][5];
	266	} else if (strncmp(argv[index], "--fd=", 5) == 0) {
	267	unixfd = atoi(&argv[index][5]);
	268	} else {
	269	usage();
	270	return EXIT_FAILURE;
	271	}
	272	}
	273
	274	if (bridge == NULL \|\| unixfd == -1) {
	275	usage();
	276	return EXIT_FAILURE;
	277	}
6f5d8671 PP	278	if (strlen(bridge) >= IFNAMSIZ) {
	279	fprintf(stderr, "name `%s' too long: %zu\n", bridge, strlen(bridge));
	280	return EXIT_FAILURE;
	281	}
7b93fadf	282
bdef79a2 CB	283	/* parse default acl file */
	284	QSIMPLEQ_INIT(&acl_list);
	285	if (parse_acl_file(DEFAULT_ACL_FILE, &acl_list) == -1) {
	286	fprintf(stderr, "failed to parse default acl file `%s'\n",
	287	DEFAULT_ACL_FILE);
	288	ret = EXIT_FAILURE;
	289	goto cleanup;
	290	}
	291
	292	/* validate bridge against acl -- default policy is to deny
	293	* according acl policy if we have a deny and allow both
	294	* then deny should always win over allow
	295	*/
	296	access_allowed = 0;
	297	access_denied = 0;
	298	QSIMPLEQ_FOREACH(acl_rule, &acl_list, entry) {
	299	switch (acl_rule->type) {
	300	case ACL_ALLOW_ALL:
	301	access_allowed = 1;
	302	break;
	303	case ACL_ALLOW:
	304	if (strcmp(bridge, acl_rule->iface) == 0) {
	305	access_allowed = 1;
	306	}
	307	break;
	308	case ACL_DENY_ALL:
	309	access_denied = 1;
	310	break;
	311	case ACL_DENY:
	312	if (strcmp(bridge, acl_rule->iface) == 0) {
	313	access_denied = 1;
	314	}
	315	break;
	316	}
	317	}
	318
	319	if ((access_allowed == 0) \|\| (access_denied == 1)) {
	320	fprintf(stderr, "access denied by acl file\n");
	321	ret = EXIT_FAILURE;
	322	goto cleanup;
	323	}
	324
7b93fadf CB	325	/* open a socket to use to control the network interfaces */
	326	ctlfd = socket(AF_INET, SOCK_STREAM, 0);
	327	if (ctlfd == -1) {
	328	fprintf(stderr, "failed to open control socket: %s\n", strerror(errno));
	329	ret = EXIT_FAILURE;
	330	goto cleanup;
	331	}
	332
	333	/* open the tap device */
	334	fd = open("/dev/net/tun", O_RDWR);
	335	if (fd == -1) {
	336	fprintf(stderr, "failed to open /dev/net/tun: %s\n", strerror(errno));
	337	ret = EXIT_FAILURE;
	338	goto cleanup;
	339	}
	340
	341	/* request a tap device, disable PI, and add vnet header support if
	342	* requested and it's available. */
	343	prep_ifreq(&ifr, "tap%d");
	344	ifr.ifr_flags = IFF_TAP\|IFF_NO_PI;
	345	if (use_vnet && has_vnet_hdr(fd)) {
	346	ifr.ifr_flags \|= IFF_VNET_HDR;
	347	}
	348
	349	if (ioctl(fd, TUNSETIFF, &ifr) == -1) {
	350	fprintf(stderr, "failed to create tun device: %s\n", strerror(errno));
	351	ret = EXIT_FAILURE;
	352	goto cleanup;
	353	}
	354
	355	/* save tap device name */
	356	snprintf(iface, sizeof(iface), "%s", ifr.ifr_name);
	357
	358	/* get the mtu of the bridge */
	359	prep_ifreq(&ifr, bridge);
	360	if (ioctl(ctlfd, SIOCGIFMTU, &ifr) == -1) {
	361	fprintf(stderr, "failed to get mtu of bridge `%s': %s\n",
	362	bridge, strerror(errno));
	363	ret = EXIT_FAILURE;
	364	goto cleanup;
	365	}
	366
	367	/* save mtu */
	368	mtu = ifr.ifr_mtu;
	369
	370	/* set the mtu of the interface based on the bridge */
	371	prep_ifreq(&ifr, iface);
	372	ifr.ifr_mtu = mtu;
	373	if (ioctl(ctlfd, SIOCSIFMTU, &ifr) == -1) {
	374	fprintf(stderr, "failed to set mtu of device `%s' to %d: %s\n",
	375	iface, mtu, strerror(errno));
	376	ret = EXIT_FAILURE;
	377	goto cleanup;
	378	}
	379
226ecabf PB	380	/* Linux uses the lowest enslaved MAC address as the MAC address of
	381	* the bridge. Set MAC address to a high value so that it doesn't
	382	* affect the MAC address of the bridge.
	383	*/
	384	if (ioctl(ctlfd, SIOCGIFHWADDR, &ifr) < 0) {
	385	fprintf(stderr, "failed to get MAC address of device `%s': %s\n",
	386	iface, strerror(errno));
	387	ret = EXIT_FAILURE;
	388	goto cleanup;
	389	}
	390	ifr.ifr_hwaddr.sa_data[0] = 0xFE;
	391	if (ioctl(ctlfd, SIOCSIFHWADDR, &ifr) < 0) {
	392	fprintf(stderr, "failed to set MAC address of device `%s': %s\n",
	393	iface, strerror(errno));
	394	ret = EXIT_FAILURE;
	395	goto cleanup;
	396	}
	397
7b93fadf CB	398	/* add the interface to the bridge */
7b93fadf CB	399	prep_ifreq(&ifr, bridge);
34309d2b CB	400	ifindex = if_nametoindex(iface);
	401	#ifndef SIOCBRADDIF
	402	ifargs[0] = BRCTL_ADD_IF;
	403	ifargs[1] = ifindex;
	404	ifargs[2] = 0;
	405	ifargs[3] = 0;
	406	ifr.ifr_data = (void *)ifargs;
	407	ret = ioctl(ctlfd, SIOCDEVPRIVATE, &ifr);
	408	#else
	409	ifr.ifr_ifindex = ifindex;
	410	ret = ioctl(ctlfd, SIOCBRADDIF, &ifr);
	411	#endif
	412	if (ret == -1) {
7b93fadf CB	413	fprintf(stderr, "failed to add interface `%s' to bridge `%s': %s\n",
	414	iface, bridge, strerror(errno));
	415	ret = EXIT_FAILURE;
	416	goto cleanup;
	417	}
	418
	419	/* bring the interface up */
	420	prep_ifreq(&ifr, iface);
	421	if (ioctl(ctlfd, SIOCGIFFLAGS, &ifr) == -1) {
	422	fprintf(stderr, "failed to get interface flags for `%s': %s\n",
	423	iface, strerror(errno));
	424	ret = EXIT_FAILURE;
	425	goto cleanup;
	426	}
	427
	428	ifr.ifr_flags \|= IFF_UP;
	429	if (ioctl(ctlfd, SIOCSIFFLAGS, &ifr) == -1) {
	430	fprintf(stderr, "failed to bring up interface `%s': %s\n",
	431	iface, strerror(errno));
	432	ret = EXIT_FAILURE;
	433	goto cleanup;
	434	}
	435
	436	/* write fd to the domain socket */
	437	if (send_fd(unixfd, fd) == -1) {
	438	fprintf(stderr, "failed to write fd to unix socket: %s\n",
	439	strerror(errno));
	440	ret = EXIT_FAILURE;
	441	goto cleanup;
	442	}
	443
	444	/* ... */
	445
	446	/* profit! */
	447
	448	cleanup:
eb3f45c5 GA	449	if (fd >= 0) {
	450	close(fd);
	451	}
	452	if (ctlfd >= 0) {
	453	close(ctlfd);
	454	}
bdef79a2 CB	455	while ((acl_rule = QSIMPLEQ_FIRST(&acl_list)) != NULL) {
	456	QSIMPLEQ_REMOVE_HEAD(&acl_list, entry);
	457	g_free(acl_rule);
	458	}
	459
7b93fadf CB	460	return ret;
7b93fadf CB	461	}