#include <sys/socket.h>

#include <linux/if.h>

#include "sd-netlink.h"

#include "sd-daemon.h"

#include "conf-parser.h"

#include "path-util.h"

#include "libudev-private.h"

#include "udev-util.h"

#include "netlink-util.h"

#include "bus-util.h"

#include "def.h"

#include "virt.h"

#include "set.h"

#include "local-addresses.h"

#include "networkd.h"

#define RCVBUF_SIZE (8*1024*1024)

const char* const network_dirs[] = {

"/etc/systemd/network",

"/run/systemd/network",

"/usr/lib/systemd/network",

#ifdef HAVE_SPLIT_USR

"/lib/systemd/network",

#endif

NULL};

static int setup_default_address_pool(Manager *m) {

AddressPool *p;

int r;

assert(m);

/* Add in the well-known private address ranges. */

r = address_pool_new_from_string(m, &p, AF_INET6, "fc00::", 7);

if (r < 0)

return r;

r = address_pool_new_from_string(m, &p, AF_INET, "192.168.0.0", 16);

if (r < 0)

return r;

r = address_pool_new_from_string(m, &p, AF_INET, "172.16.0.0", 12);

if (r < 0)

return r;

r = address_pool_new_from_string(m, &p, AF_INET, "10.0.0.0", 8);

if (r < 0)

return r;

return 0;

}

static int on_bus_retry(sd_event_source *s, usec_t usec, void *userdata) {

Manager *m = userdata;

assert(s);

assert(m);

m->bus_retry_event_source = sd_event_source_unref(m->bus_retry_event_source);

manager_connect_bus(m);

return 0;

}

static int manager_reset_all(Manager *m) {

Link *link;

Iterator i;

int r;

assert(m);

HASHMAP_FOREACH(link, m->links, i) {

r = link_carrier_reset(link);

if (r < 0)

log_link_warning_errno(link, r, "Could not reset carrier: %m");

}

return 0;

}

static int match_prepare_for_sleep(sd_bus_message *message, void *userdata, sd_bus_error *ret_error) {

Manager *m = userdata;

int b, r;

assert(message);

r = sd_bus_message_read(message, "b", &b);

if (r < 0) {

log_debug_errno(r, "Failed to parse PrepareForSleep signal: %m");

return 0;

}

if (b)

return 0;

log_debug("Coming back from suspend, resetting all connections...");

manager_reset_all(m);

return 0;

}

int manager_connect_bus(Manager *m) {

int r;

assert(m);

r = sd_bus_default_system(&m->bus);

if (r == -ENOENT) {

/* We failed to connect? Yuck, we must be in early

log_debug_errno(r, "Failed to connect to bus, trying again in 5s: %m");

r = sd_event_add_time(m->event, &m->bus_retry_event_source, CLOCK_MONOTONIC, now(CLOCK_MONOTONIC) + 5*USEC_PER_SEC, 0, on_bus_retry, m);

if (r < 0)

return log_error_errno(r, "Failed to install bus reconnect time event: %m");

return 0;

}

if (r < 0)

return r;

r = sd_bus_add_match(m->bus, &m->prepare_for_sleep_slot,

"type='signal',"

"sender='org.freedesktop.login1',"

"interface='org.freedesktop.login1.Manager',"

"member='PrepareForSleep',"

"path='/org/freedesktop/login1'",

match_prepare_for_sleep,

m);

if (r < 0)

return log_error_errno(r, "Failed to add match for PrepareForSleep: %m");

r = sd_bus_add_object_vtable(m->bus, NULL, "/org/freedesktop/network1", "org.freedesktop.network1.Manager", manager_vtable, m);

if (r < 0)

return log_error_errno(r, "Failed to add manager object vtable: %m");

r = sd_bus_add_fallback_vtable(m->bus, NULL, "/org/freedesktop/network1/link", "org.freedesktop.network1.Link", link_vtable, link_object_find, m);

if (r < 0)

return log_error_errno(r, "Failed to add link object vtable: %m");

r = sd_bus_add_node_enumerator(m->bus, NULL, "/org/freedesktop/network1/link", link_node_enumerator, m);

if (r < 0)

return log_error_errno(r, "Failed to add link enumerator: %m");

r = sd_bus_add_fallback_vtable(m->bus, NULL, "/org/freedesktop/network1/network", "org.freedesktop.network1.Network", network_vtable, network_object_find, m);

if (r < 0)

return log_error_errno(r, "Failed to add network object vtable: %m");

r = sd_bus_add_node_enumerator(m->bus, NULL, "/org/freedesktop/network1/network", network_node_enumerator, m);

if (r < 0)

return log_error_errno(r, "Failed to add network enumerator: %m");

r = sd_bus_request_name(m->bus, "org.freedesktop.network1", 0);

if (r < 0)

return log_error_errno(r, "Failed to register name: %m");

r = sd_bus_attach_event(m->bus, m->event, 0);

if (r < 0)

return log_error_errno(r, "Failed to attach bus to event loop: %m");

return 0;

}

static int manager_udev_process_link(Manager *m, struct udev_device *device) {

Link *link = NULL;

int r, ifindex;

assert(m);

assert(device);

if (!streq_ptr(udev_device_get_action(device), "add"))

return 0;

ifindex = udev_device_get_ifindex(device);

if (ifindex <= 0) {

log_debug("Ignoring udev ADD event for device with invalid ifindex");

return 0;

}

r = link_get(m, ifindex, &link);

if (r == -ENODEV)

return 0;

else if (r < 0)

return r;

r = link_initialized(link, device);

if (r < 0)

return r;

return 0;

}

static int manager_dispatch_link_udev(sd_event_source *source, int fd, uint32_t revents, void *userdata) {

Manager *m = userdata;

struct udev_monitor *monitor = m->udev_monitor;

_cleanup_udev_device_unref_ struct udev_device *device = NULL;

device = udev_monitor_receive_device(monitor);

if (!device)

return -ENOMEM;

manager_udev_process_link(m, device);

return 0;

}

static int manager_connect_udev(Manager *m) {

int r;

/* udev does not initialize devices inside containers,

if (detect_container() > 0)

return 0;

m->udev = udev_new();

if (!m->udev)

return -ENOMEM;

m->udev_monitor = udev_monitor_new_from_netlink(m->udev, "udev");

if (!m->udev_monitor)

return -ENOMEM;

r = udev_monitor_filter_add_match_subsystem_devtype(m->udev_monitor, "net", NULL);

if (r < 0)

return log_error_errno(r, "Could not add udev monitor filter: %m");

r = udev_monitor_enable_receiving(m->udev_monitor);

if (r < 0) {

log_error("Could not enable udev monitor");

return r;

}

r = sd_event_add_io(m->event,

&m->udev_event_source,

udev_monitor_get_fd(m->udev_monitor),

EPOLLIN, manager_dispatch_link_udev,

m);

if (r < 0)

return r;

r = sd_event_source_set_description(m->udev_event_source, "networkd-udev");

if (r < 0)

return r;

return 0;

}

int manager_rtnl_process_address(sd_netlink *rtnl, sd_netlink_message *message, void *userdata) {

Manager *m = userdata;

Link *link = NULL;

uint16_t type;

_cleanup_address_free_ Address *address = NULL;

unsigned char flags;

Address *existing = NULL;

char buf[INET6_ADDRSTRLEN], valid_buf[FORMAT_TIMESPAN_MAX];

const char *valid_str = NULL;

int r, ifindex;

assert(rtnl);

assert(message);

assert(m);

if (sd_netlink_message_is_error(message)) {

r = sd_netlink_message_get_errno(message);

if (r < 0)

log_warning_errno(r, "rtnl: failed to receive address: %m");

return 0;

}

r = sd_netlink_message_get_type(message, &type);

if (r < 0) {

log_warning_errno(r, "rtnl: could not get message type: %m");

return 0;

} else if (type != RTM_NEWADDR && type != RTM_DELADDR) {

log_warning("rtnl: received unexpected message type when processing address");

return 0;

}

r = sd_rtnl_message_addr_get_ifindex(message, &ifindex);

if (r < 0) {

log_warning_errno(r, "rtnl: could not get ifindex from address: %m");

return 0;

} else if (ifindex <= 0) {

log_warning("rtnl: received address message with invalid ifindex: %d", ifindex);

return 0;

} else {

r = link_get(m, ifindex, &link);

if (r < 0 || !link) {

/* when enumerating we might be out of sync, but we will

if (!m->enumerating)

log_warning("rtnl: received address for nonexistent link (%d), ignoring", ifindex);

return 0;

}

}

r = address_new(&address);

if (r < 0)

return r;

r = sd_rtnl_message_addr_get_family(message, &address->family);

if (r < 0 || !IN_SET(address->family, AF_INET, AF_INET6)) {

log_link_warning(link, "rtnl: received address with invalid family, ignoring.");

return 0;

}

r = sd_rtnl_message_addr_get_prefixlen(message, &address->prefixlen);

if (r < 0) {

log_link_warning_errno(link, r, "rtnl: received address with invalid prefixlen, ignoring: %m");

return 0;

}

r = sd_rtnl_message_addr_get_scope(message, &address->scope);

if (r < 0) {

log_link_warning_errno(link, r, "rtnl: received address with invalid scope, ignoring: %m");

return 0;

}

r = sd_rtnl_message_addr_get_flags(message, &flags);

if (r < 0) {

log_link_warning_errno(link, r, "rtnl: received address with invalid flags, ignoring: %m");

return 0;

}

address->flags = flags;

switch (address->family) {

case AF_INET:

r = sd_netlink_message_read_in_addr(message, IFA_LOCAL, &address->in_addr.in);

if (r < 0) {

log_link_warning_errno(link, r, "rtnl: received address without valid address, ignoring: %m");

return 0;

}

break;

case AF_INET6:

r = sd_netlink_message_read_in6_addr(message, IFA_ADDRESS, &address->in_addr.in6);

if (r < 0) {

log_link_warning_errno(link, r, "rtnl: received address without valid address, ignoring: %m");

return 0;

}

break;

default:

assert_not_reached("invalid address family");

}

if (!inet_ntop(address->family, &address->in_addr, buf, INET6_ADDRSTRLEN)) {

log_link_warning(link, "Could not print address");

return 0;

}

r = sd_netlink_message_read_cache_info(message, IFA_CACHEINFO, &address->cinfo);

if (r >= 0) {

if (address->cinfo.ifa_valid == CACHE_INFO_INFINITY_LIFE_TIME)

valid_str = "ever";

else

valid_str = format_timespan(valid_buf, FORMAT_TIMESPAN_MAX,

address->cinfo.ifa_valid * USEC_PER_SEC,

USEC_PER_SEC);

}

address_get(link, address->family, &address->in_addr, address->prefixlen, &existing);

switch (type) {

case RTM_NEWADDR:

if (existing) {

log_link_debug(link, "Updating address: %s/%u (valid for %s)", buf, address->prefixlen, valid_str);

existing->scope = address->scope;

existing->flags = address->flags;

existing->cinfo = address->cinfo;

} else {

r = address_add(link, address);

if (r < 0) {

log_link_warning_errno(link, r, "Failed to add address %s/%u: %m", buf, address->prefixlen);

return 0;

} else

log_link_debug(link, "Adding address: %s/%u (valid for %s)", buf, address->prefixlen, valid_str);

address_establish(address, link);

address = NULL;

link_save(link);

}

break;

case RTM_DELADDR:

if (existing) {

log_link_debug(link, "Removing address: %s/%u (valid for %s)", buf, address->prefixlen, valid_str);

address_release(existing, link);

address_free(existing);

} else

log_link_warning(link, "Removing non-existent address: %s/%u (valid for %s)", buf, address->prefixlen, valid_str);

break;

default:

assert_not_reached("Received invalid RTNL message type");

}

return 1;

}

static int manager_rtnl_process_link(sd_netlink *rtnl, sd_netlink_message *message, void *userdata) {

Manager *m = userdata;

Link *link = NULL;

NetDev *netdev = NULL;

uint16_t type;

const char *name;

int r, ifindex;

assert(rtnl);

assert(message);

assert(m);

if (sd_netlink_message_is_error(message)) {

r = sd_netlink_message_get_errno(message);

if (r < 0)

log_warning_errno(r, "rtnl: Could not receive link: %m");

return 0;

}

r = sd_netlink_message_get_type(message, &type);

if (r < 0) {

log_warning_errno(r, "rtnl: Could not get message type: %m");

return 0;

} else if (type != RTM_NEWLINK && type != RTM_DELLINK) {

log_warning("rtnl: Received unexpected message type when processing link");

return 0;

}

r = sd_rtnl_message_link_get_ifindex(message, &ifindex);

if (r < 0) {

log_warning_errno(r, "rtnl: Could not get ifindex from link: %m");

return 0;

} else if (ifindex <= 0) {

log_warning("rtnl: received link message with invalid ifindex: %d", ifindex);

return 0;

} else

link_get(m, ifindex, &link);

r = sd_netlink_message_read_string(message, IFLA_IFNAME, &name);

if (r < 0) {

log_warning_errno(r, "rtnl: Received link message without ifname: %m");

return 0;

} else

netdev_get(m, name, &netdev);

switch (type) {

case RTM_NEWLINK:

if (!link) {

/* link is new, so add it */

r = link_add(m, message, &link);

if (r < 0) {

log_warning_errno(r, "Could not add new link: %m");

return 0;

}

}

if (netdev) {

/* netdev exists, so make sure the ifindex matches */

r = netdev_set_ifindex(netdev, message);

if (r < 0) {

log_warning_errno(r, "Could not set ifindex on netdev: %m");

return 0;

}

}

r = link_update(link, message);

if (r < 0)

return 0;

break;

case RTM_DELLINK:

link_drop(link);

netdev_drop(netdev);

break;

default:

assert_not_reached("Received invalid RTNL message type.");

}

return 1;

}

static int systemd_netlink_fd(void) {

int n, fd, rtnl_fd = -EINVAL;

n = sd_listen_fds(true);

if (n <= 0)

return -EINVAL;

for (fd = SD_LISTEN_FDS_START; fd < SD_LISTEN_FDS_START + n; fd ++) {

if (sd_is_socket(fd, AF_NETLINK, SOCK_RAW, -1) > 0) {

if (rtnl_fd >= 0)

return -EINVAL;

rtnl_fd = fd;

}

}

return rtnl_fd;

}

static int manager_connect_rtnl(Manager *m) {

int fd, r;

assert(m);

fd = systemd_netlink_fd();

if (fd < 0)

r = sd_netlink_open(&m->rtnl);

else

r = sd_netlink_open_fd(&m->rtnl, fd);

if (r < 0)

return r;

r = sd_netlink_inc_rcvbuf(m->rtnl, RCVBUF_SIZE);

if (r < 0)

return r;

r = sd_netlink_attach_event(m->rtnl, m->event, 0);

if (r < 0)

return r;

r = sd_netlink_add_match(m->rtnl, RTM_NEWLINK, &manager_rtnl_process_link, m);

if (r < 0)

return r;

r = sd_netlink_add_match(m->rtnl, RTM_DELLINK, &manager_rtnl_process_link, m);

if (r < 0)

return r;

r = sd_netlink_add_match(m->rtnl, RTM_NEWADDR, &manager_rtnl_process_address, m);

if (r < 0)

return r;

r = sd_netlink_add_match(m->rtnl, RTM_DELADDR, &manager_rtnl_process_address, m);

if (r < 0)

return r;

return 0;

}

int manager_new(Manager **ret) {

_cleanup_manager_free_ Manager *m = NULL;

int r;

m = new0(Manager, 1);

if (!m)

return -ENOMEM;

m->state_file = strdup("/run/systemd/netif/state");

if (!m->state_file)

return -ENOMEM;

r = sd_event_default(&m->event);

if (r < 0)

return r;

sd_event_set_watchdog(m->event, true);

sd_event_add_signal(m->event, NULL, SIGTERM, NULL, NULL);

sd_event_add_signal(m->event, NULL, SIGINT, NULL, NULL);

r = manager_connect_rtnl(m);

if (r < 0)

return r;

r = manager_connect_udev(m);

if (r < 0)

return r;

m->netdevs = hashmap_new(&string_hash_ops);

if (!m->netdevs)

return -ENOMEM;

LIST_HEAD_INIT(m->networks);

r = setup_default_address_pool(m);

if (r < 0)

return r;

*ret = m;

m = NULL;

return 0;

}

void manager_free(Manager *m) {

Network *network;

NetDev *netdev;

Link *link;

AddressPool *pool;

if (!m)

return;

free(m->state_file);

while ((link = hashmap_first(m->links)))

link_unref(link);

hashmap_free(m->links);

while ((network = m->networks))

network_free(network);

hashmap_free(m->networks_by_name);

while ((netdev = hashmap_first(m->netdevs)))

netdev_unref(netdev);

hashmap_free(m->netdevs);

while ((pool = m->address_pools))

address_pool_free(pool);

sd_netlink_unref(m->rtnl);

sd_event_unref(m->event);

sd_event_source_unref(m->udev_event_source);

udev_monitor_unref(m->udev_monitor);

udev_unref(m->udev);

sd_bus_unref(m->bus);

sd_bus_slot_unref(m->prepare_for_sleep_slot);

sd_event_source_unref(m->bus_retry_event_source);

free(m);

}

static bool manager_check_idle(void *userdata) {

Manager *m = userdata;

Link *link;

Iterator i;

assert(m);

HASHMAP_FOREACH(link, m->links, i) {

/* we are not woken on udev activity, so let's just wait for the

if (link->state == LINK_STATE_PENDING)

return false;

if (!link->network)

continue;

/* we are not woken on netork activity, so let's stay around */

if (link_lldp_enabled(link) ||

link_ipv4ll_enabled(link) ||

link_dhcp4_server_enabled(link) ||

link_dhcp4_enabled(link) ||

link_dhcp6_enabled(link))

return false;

}

return true;

}

int manager_run(Manager *m) {

assert(m);

if (m->bus)

return bus_event_loop_with_idle(

m->event,

m->bus,

"org.freedesktop.network1",

DEFAULT_EXIT_USEC,

manager_check_idle,

m);

else

/* failed to connect to the bus, so we lose exit-on-idle logic,

return sd_event_loop(m->event);

}

int manager_load_config(Manager *m) {

int r;

/* update timestamp */

paths_check_timestamp(network_dirs, &m->network_dirs_ts_usec, true);

r = netdev_load(m);

if (r < 0)

return r;

r = network_load(m);

if (r < 0)

return r;

return 0;

}

bool manager_should_reload(Manager *m) {

return paths_check_timestamp(network_dirs, &m->network_dirs_ts_usec, false);

}

int manager_rtnl_enumerate_links(Manager *m) {

_cleanup_netlink_message_unref_ sd_netlink_message *req = NULL, *reply = NULL;

sd_netlink_message *link;

int r;

assert(m);

assert(m->rtnl);

r = sd_rtnl_message_new_link(m->rtnl, &req, RTM_GETLINK, 0);

if (r < 0)

return r;

r = sd_netlink_message_request_dump(req, true);

if (r < 0)

return r;

r = sd_netlink_call(m->rtnl, req, 0, &reply);

if (r < 0)

return r;

for (link = reply; link; link = sd_netlink_message_next(link)) {

int k;

m->enumerating = true;

k = manager_rtnl_process_link(m->rtnl, link, m);

if (k < 0)

r = k;

m->enumerating = false;

}

return r;

}

int manager_rtnl_enumerate_addresses(Manager *m) {

_cleanup_netlink_message_unref_ sd_netlink_message *req = NULL, *reply = NULL;

sd_netlink_message *addr;

int r;

assert(m);

assert(m->rtnl);

r = sd_rtnl_message_new_addr(m->rtnl, &req, RTM_GETADDR, 0, 0);

if (r < 0)

return r;

r = sd_netlink_message_request_dump(req, true);

if (r < 0)

return r;

r = sd_netlink_call(m->rtnl, req, 0, &reply);

if (r < 0)

return r;

for (addr = reply; addr; addr = sd_netlink_message_next(addr)) {

int k;

m->enumerating = true;

k = manager_rtnl_process_address(m->rtnl, addr, m);

if (k < 0)

r = k;

m->enumerating = false;

}

return r;

}

static int set_put_in_addr(Set *s, const struct in_addr *address) {

char *p;

int r;

assert(s);

r = in_addr_to_string(AF_INET, (const union in_addr_union*) address, &p);

if (r < 0)

return r;

r = set_consume(s, p);

if (r == -EEXIST)

return 0;

return r;

}

static int set_put_in_addrv(Set *s, const struct in_addr *addresses, int n) {

int r, i, c = 0;

assert(s);

assert(n <= 0 || addresses);

for (i = 0; i < n; i++) {

r = set_put_in_addr(s, addresses+i);

if (r < 0)

return r;

c += r;

}

return c;

}

static void print_string_set(FILE *f, const char *field, Set *s) {

bool space = false;

Iterator i;

char *p;

if (set_isempty(s))

return;

fputs(field, f);

SET_FOREACH(p, s, i) {

if (space)

fputc(' ', f);

fputs(p, f);

space = true;

}

fputc('\n', f);

}

int manager_save(Manager *m) {

_cleanup_set_free_free_ Set *dns = NULL, *ntp = NULL, *domains = NULL;

Link *link;

Iterator i;

_cleanup_free_ char *temp_path = NULL;

_cleanup_fclose_ FILE *f = NULL;

LinkOperationalState operstate = LINK_OPERSTATE_OFF;

const char *operstate_str;

int r;

assert(m);

assert(m->state_file);

/* We add all NTP and DNS server to a set, to filter out duplicates */

dns = set_new(&string_hash_ops);

if (!dns)

return -ENOMEM;

ntp = set_new(&string_hash_ops);

if (!ntp)

return -ENOMEM;

domains = set_new(&string_hash_ops);

if (!domains)

return -ENOMEM;

HASHMAP_FOREACH(link, m->links, i) {

if (link->flags & IFF_LOOPBACK)

continue;

if (link->operstate > operstate)

operstate = link->operstate;

if (!link->network)

continue;

/* First add the static configured entries */

r = set_put_strdupv(dns, link->network->dns);

if (r < 0)

return r;

r = set_put_strdupv(ntp, link->network->ntp);

if (r < 0)

return r;

r = set_put_strdupv(domains, link->network->domains);

if (r < 0)

return r;

if (!link->dhcp_lease)

continue;

/* Secondly, add the entries acquired via DHCP */

if (link->network->dhcp_dns) {

const struct in_addr *addresses;

r = sd_dhcp_lease_get_dns(link->dhcp_lease, &addresses);

if (r > 0) {

r = set_put_in_addrv(dns, addresses, r);

if (r < 0)

return r;

} else if (r < 0 && r != -ENODATA)

return r;

}

if (link->network->dhcp_ntp) {

const struct in_addr *addresses;

r = sd_dhcp_lease_get_ntp(link->dhcp_lease, &addresses);

if (r > 0) {

r = set_put_in_addrv(ntp, addresses, r);

if (r < 0)

return r;

} else if (r < 0 && r != -ENODATA)

return r;

}

if (link->network->dhcp_domains) {

const char *domainname;

r = sd_dhcp_lease_get_domainname(link->dhcp_lease, &domainname);

if (r >= 0) {

r = set_put_strdup(domains, domainname);

if (r < 0)

return r;

} else if (r != -ENODATA)

return r;

}

}

operstate_str = link_operstate_to_string(operstate);

assert(operstate_str);

r = fopen_temporary(m->state_file, &f, &temp_path);

if (r < 0)

return r;

fchmod(fileno(f), 0644);

fprintf(f,

"# This is private data. Do not parse.\n"

"OPER_STATE=%s\n", operstate_str);

print_string_set(f, "DNS=", dns);

print_string_set(f, "NTP=", ntp);

print_string_set(f, "DOMAINS=", domains);

r = fflush_and_check(f);

if (r < 0)

goto fail;

if (rename(temp_path, m->state_file) < 0) {

r = -errno;

goto fail;

}

if (m->operational_state != operstate) {

m->operational_state = operstate;

r = manager_send_changed(m, "OperationalState", NULL);

if (r < 0)

log_error_errno(r, "Could not emit changed OperationalState: %m");

}

return 0;

fail:

(void) unlink(m->state_file);

(void) unlink(temp_path);

return log_error_errno(r, "Failed to save network state to %s: %m", m->state_file);

}

int manager_address_pool_acquire(Manager *m, int family, unsigned prefixlen, union in_addr_union *found) {

AddressPool *p;

int r;

assert(m);

assert(prefixlen > 0);

assert(found);

LIST_FOREACH(address_pools, p, m->address_pools) {

if (p->family != family)

continue;

r = address_pool_acquire(p, prefixlen, found);

if (r != 0)

return r;

}

return 0;

}

Link* manager_find_uplink(Manager *m, Link *exclude) {

_cleanup_free_ struct local_address *gateways = NULL;

int n, i;

assert(m);

/* Looks for a suitable "uplink", via black magic: an

n = local_gateways(m->rtnl, 0, AF_UNSPEC, &gateways);

if (n < 0) {

log_warning_errno(n, "Failed to determine list of default gateways: %m");

return NULL;

}

for (i = 0; i < n; i++) {

Link *link;

link = hashmap_get(m->links, INT_TO_PTR(gateways[i].ifindex));

if (!link) {

log_debug("Weird, found a gateway for a link we don't know. Ignoring.");

continue;

}

if (link == exclude)

continue;

if (link->operstate < LINK_OPERSTATE_ROUTABLE)

continue;

return link;

}

return NULL;

}