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/* SPDX-License-Identifier: LGPL-2.1+ */
#include <errno.h>
#include <fcntl.h>
#include <linux/if_tun.h>
#include <net/if.h>
#include <netinet/if_ether.h>
#include <sys/ioctl.h>
#include <sys/stat.h>
#include <sys/types.h>
#include "alloc-util.h"
#include "fd-util.h"
#include "netdev/tuntap.h"
#include "user-util.h"
#define TUN_DEV "/dev/net/tun"
static int netdev_fill_tuntap_message(NetDev *netdev, struct ifreq *ifr) {
TunTap *t;
assert(netdev);
assert(netdev->ifname);
assert(ifr);
if (netdev->kind == NETDEV_KIND_TAP) {
t = TAP(netdev);
ifr->ifr_flags |= IFF_TAP;
} else {
t = TUN(netdev);
ifr->ifr_flags |= IFF_TUN;
}
if (!t->packet_info)
ifr->ifr_flags |= IFF_NO_PI;
if (t->one_queue)
ifr->ifr_flags |= IFF_ONE_QUEUE;
if (t->multi_queue)
ifr->ifr_flags |= IFF_MULTI_QUEUE;
if (t->vnet_hdr)
ifr->ifr_flags |= IFF_VNET_HDR;
strncpy(ifr->ifr_name, netdev->ifname, IFNAMSIZ-1);
return 0;
}
static int netdev_tuntap_add(NetDev *netdev, struct ifreq *ifr) {
_cleanup_close_ int fd;
TunTap *t = NULL;
const char *user;
const char *group;
uid_t uid;
gid_t gid;
int r;
assert(netdev);
assert(ifr);
fd = open(TUN_DEV, O_RDWR|O_CLOEXEC);
if (fd < 0)
return log_netdev_error_errno(netdev, -errno, "Failed to open tun dev: %m");
if (ioctl(fd, TUNSETIFF, ifr) < 0)
return log_netdev_error_errno(netdev, -errno, "TUNSETIFF failed on tun dev: %m");
if (netdev->kind == NETDEV_KIND_TAP)
t = TAP(netdev);
else
t = TUN(netdev);
assert(t);
if (t->user_name) {
user = t->user_name;
r = get_user_creds(&user, &uid, NULL, NULL, NULL, USER_CREDS_ALLOW_MISSING);
if (r < 0)
return log_netdev_error_errno(netdev, r, "Cannot resolve user name %s: %m", t->user_name);
if (ioctl(fd, TUNSETOWNER, uid) < 0)
return log_netdev_error_errno(netdev, -errno, "TUNSETOWNER failed on tun dev: %m");
}
if (t->group_name) {
group = t->group_name;
r = get_group_creds(&group, &gid, USER_CREDS_ALLOW_MISSING);
if (r < 0)
return log_netdev_error_errno(netdev, r, "Cannot resolve group name %s: %m", t->group_name);
if (ioctl(fd, TUNSETGROUP, gid) < 0)
return log_netdev_error_errno(netdev, -errno, "TUNSETGROUP failed on tun dev: %m");
}
if (ioctl(fd, TUNSETPERSIST, 1) < 0)
return log_netdev_error_errno(netdev, -errno, "TUNSETPERSIST failed on tun dev: %m");
return 0;
}
static int netdev_create_tuntap(NetDev *netdev) {
struct ifreq ifr = {};
int r;
r = netdev_fill_tuntap_message(netdev, &ifr);
if (r < 0)
return r;
return netdev_tuntap_add(netdev, &ifr);
}
static void tuntap_done(NetDev *netdev) {
TunTap *t = NULL;
assert(netdev);
if (netdev->kind == NETDEV_KIND_TUN)
t = TUN(netdev);
else
t = TAP(netdev);
assert(t);
t->user_name = mfree(t->user_name);
t->group_name = mfree(t->group_name);
}
static int tuntap_verify(NetDev *netdev, const char *filename) {
assert(netdev);
if (netdev->mtu != 0)
log_netdev_warning(netdev, "MTU configured for %s, ignoring", netdev_kind_to_string(netdev->kind));
if (netdev->mac)
log_netdev_warning(netdev, "MAC configured for %s, ignoring", netdev_kind_to_string(netdev->kind));
return 0;
}
const NetDevVTable tun_vtable = {
.object_size = sizeof(TunTap),
.sections = "Match\0NetDev\0Tun\0",
.config_verify = tuntap_verify,
.done = tuntap_done,
.create = netdev_create_tuntap,
.create_type = NETDEV_CREATE_INDEPENDENT,
};
const NetDevVTable tap_vtable = {
.object_size = sizeof(TunTap),
.sections = "Match\0NetDev\0Tap\0",
.config_verify = tuntap_verify,
.done = tuntap_done,
.create = netdev_create_tuntap,
.create_type = NETDEV_CREATE_INDEPENDENT,
};
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