/* SPDX-License-Identifier: LGPL-2.1-or-later */ /* Make sure the net/if.h header is included before any linux/ one */ #include #include #include #include #include #include #include #include #include "alloc-util.h" #include "daemon-util.h" #include "fd-util.h" #include "networkd-link.h" #include "networkd-manager.h" #include "socket-util.h" #include "tuntap.h" #include "user-util.h" #define TUN_DEV "/dev/net/tun" static TunTap* TUNTAP(NetDev *netdev) { assert(netdev); switch (netdev->kind) { case NETDEV_KIND_TAP: return TAP(netdev); case NETDEV_KIND_TUN: return TUN(netdev); default: return NULL; } } DEFINE_PRIVATE_HASH_OPS_FULL(named_fd_hash_ops, char, string_hash_func, string_compare_func, free, void, close_fd_ptr); int manager_add_tuntap_fd(Manager *m, int fd, const char *name) { _cleanup_free_ char *tuntap_name = NULL; const char *p; int r; assert(m); assert(fd >= 0); assert(name); p = startswith(name, "tuntap-"); if (!p) return log_debug_errno(SYNTHETIC_ERRNO(EINVAL), "Received unknown fd (%s).", name); if (!ifname_valid(p)) return log_debug_errno(SYNTHETIC_ERRNO(EINVAL), "Received tuntap fd with invalid name (%s).", p); tuntap_name = strdup(p); if (!tuntap_name) return log_oom_debug(); r = hashmap_ensure_put(&m->tuntap_fds_by_name, &named_fd_hash_ops, tuntap_name, FD_TO_PTR(fd)); if (r < 0) return log_debug_errno(r, "Failed to store tuntap fd: %m"); TAKE_PTR(tuntap_name); return 0; } void manager_clear_unmanaged_tuntap_fds(Manager *m) { char *name; void *p; assert(m); while ((p = hashmap_steal_first_key_and_value(m->tuntap_fds_by_name, (void**) &name))) { close_and_notify_warn(PTR_TO_FD(p), name); name = mfree(name); } } static int tuntap_take_fd(NetDev *netdev) { _cleanup_free_ char *name = NULL; void *p; int r; assert(netdev); assert(netdev->manager); r = link_get_by_name(netdev->manager, netdev->ifname, NULL); if (r < 0) return r; p = hashmap_remove2(netdev->manager->tuntap_fds_by_name, netdev->ifname, (void**) &name); if (!p) return -ENOENT; log_netdev_debug(netdev, "Found file descriptor in fd store."); return PTR_TO_FD(p); } static int netdev_create_tuntap(NetDev *netdev) { _cleanup_close_ int fd = -EBADF; struct ifreq ifr = {}; TunTap *t; int r; assert(netdev); t = TUNTAP(netdev); assert(t); fd = TAKE_FD(t->fd); if (fd < 0) fd = tuntap_take_fd(netdev); if (fd < 0) 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 (netdev->kind == NETDEV_KIND_TAP) ifr.ifr_flags |= IFF_TAP; else ifr.ifr_flags |= IFF_TUN; if (!t->packet_info) ifr.ifr_flags |= IFF_NO_PI; 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); if (ioctl(fd, TUNSETIFF, &ifr) < 0) return log_netdev_error_errno(netdev, errno, "TUNSETIFF failed: %m"); if (t->multi_queue) { /* If we don't detach the queue, the kernel will send packets to our queue and they * will be dropped because we never read them, which is especially important in case * of KeepCarrier option which persists open FD. So detach our queue right after * device create/attach to make kernel not send the packets to it. The option is * available for multi-queue devices only. * * See https://github.com/systemd/systemd/pull/30504 for details. */ struct ifreq detach_request = { .ifr_flags = IFF_DETACH_QUEUE }; if (ioctl(fd, TUNSETQUEUE, &detach_request) < 0) return log_netdev_error_errno(netdev, errno, "TUNSETQUEUE failed: %m"); } if (t->user_name) { const char *user = t->user_name; uid_t uid; 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: %m"); } if (t->group_name) { const char *group = t->group_name; gid_t gid; 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: %m"); } if (ioctl(fd, TUNSETPERSIST, 1) < 0) return log_netdev_error_errno(netdev, errno, "TUNSETPERSIST failed: %m"); if (t->keep_fd) { t->fd = TAKE_FD(fd); (void) notify_push_fdf(t->fd, "tuntap-%s", netdev->ifname); } return 0; } static void tuntap_init(NetDev *netdev) { TunTap *t; assert(netdev); t = TUNTAP(netdev); assert(t); t->fd = -EBADF; } static void tuntap_drop(NetDev *netdev) { TunTap *t; assert(netdev); t = TUNTAP(netdev); assert(t); t->fd = close_and_notify_warn(t->fd, netdev->ifname); } static void tuntap_done(NetDev *netdev) { TunTap *t; assert(netdev); t = TUNTAP(netdev); assert(t); t->fd = safe_close(t->fd); 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, "MTUBytes= configured for %s device in %s will be ignored.\n" "Please set it in the corresponding .network file.", netdev_kind_to_string(netdev->kind), filename); if (netdev->hw_addr.length > 0) log_netdev_warning(netdev, "MACAddress= configured for %s device in %s will be ignored.\n" "Please set it in the corresponding .network file.", netdev_kind_to_string(netdev->kind), filename); return 0; } const NetDevVTable tun_vtable = { .object_size = sizeof(TunTap), .sections = NETDEV_COMMON_SECTIONS "Tun\0", .config_verify = tuntap_verify, .init = tuntap_init, .drop = tuntap_drop, .done = tuntap_done, .create = netdev_create_tuntap, .create_type = NETDEV_CREATE_INDEPENDENT, .iftype = ARPHRD_NONE, }; const NetDevVTable tap_vtable = { .object_size = sizeof(TunTap), .sections = NETDEV_COMMON_SECTIONS "Tap\0", .config_verify = tuntap_verify, .init = tuntap_init, .drop = tuntap_drop, .done = tuntap_done, .create = netdev_create_tuntap, .create_type = NETDEV_CREATE_INDEPENDENT, .iftype = ARPHRD_ETHER, };