/* SPDX-License-Identifier: LGPL-2.1+ */
#include <netinet/ether.h>
#include <linux/if.h>
#include "alloc-util.h"
#include "dhcp-lease-internal.h"
#include "hostname-util.h"
#include "parse-util.h"
#include "netdev/vrf.h"
#include "network-internal.h"
#include "networkd-link.h"
#include "networkd-manager.h"
#include "networkd-network.h"
#include "string-util.h"
#include "sysctl-util.h"
static int dhcp4_route_handler(sd_netlink *rtnl, sd_netlink_message *m,
void *userdata) {
_cleanup_(link_unrefp) Link *link = userdata;
int r;
assert(link);
assert(link->dhcp4_messages > 0);
link->dhcp4_messages--;
r = sd_netlink_message_get_errno(m);
if (r < 0 && r != -EEXIST) {
log_link_error_errno(link, r, "Could not set DHCPv4 route: %m");
link_enter_failed(link);
}
if (link->dhcp4_messages == 0) {
link->dhcp4_configured = true;
link_check_ready(link);
}
return 1;
}
static int route_scope_from_address(const Route *route, const struct in_addr *self_addr) {
assert(route);
assert(self_addr);
if (in_addr_is_localhost(AF_INET, &route->dst) ||
(self_addr->s_addr && route->dst.in.s_addr == self_addr->s_addr))
return RT_SCOPE_HOST;
else if (in4_addr_is_null(&route->gw.in))
return RT_SCOPE_LINK;
else
return RT_SCOPE_UNIVERSE;
}
static int link_set_dhcp_routes(Link *link) {
_cleanup_free_ sd_dhcp_route **static_routes = NULL;
bool classless_route = false, static_route = false;
struct in_addr gateway, address;
int r, n, i;
uint32_t table;
assert(link);
if (!link->dhcp_lease) /* link went down while we configured the IP addresses? */
return 0;
if (!link->network) /* link went down while we configured the IP addresses? */
return 0;
if (!link->network->dhcp_use_routes)
return 0;
/* When the interface is part of an VRF use the VRFs routing table, unless
* there is a another table specified. */
table = link->network->dhcp_route_table;
if (!link->network->dhcp_route_table_set && link->network->vrf != NULL)
table = VRF(link->network->vrf)->table;
r = sd_dhcp_lease_get_address(link->dhcp_lease, &address);
if (r < 0)
return log_link_warning_errno(link, r, "DHCP error: could not get address: %m");
n = sd_dhcp_lease_get_routes(link->dhcp_lease, &static_routes);
if (n < 0)
log_link_debug_errno(link, n, "DHCP error: could not get routes: %m");
for (i = 0; i < n; i++) {
if (static_routes[i]->option == SD_DHCP_OPTION_CLASSLESS_STATIC_ROUTE)
classless_route = true;
if (static_routes[i]->option == SD_DHCP_OPTION_STATIC_ROUTE)
static_route = true;
}
for (i = 0; i < n; i++) {
_cleanup_(route_freep) Route *route = NULL;
/* if the DHCP server returns both a Classless Static Routes option and a Static Routes option,
the DHCP client MUST ignore the Static Routes option. */
if (classless_route && static_routes[i]->option == SD_DHCP_OPTION_STATIC_ROUTE)
continue;
r = route_new(&route);
if (r < 0)
return log_link_error_errno(link, r, "Could not allocate route: %m");
route->family = AF_INET;
route->protocol = RTPROT_DHCP;
assert_se(sd_dhcp_route_get_gateway(static_routes[i], &route->gw.in) >= 0);
assert_se(sd_dhcp_route_get_destination(static_routes[i], &route->dst.in) >= 0);
assert_se(sd_dhcp_route_get_destination_prefix_length(static_routes[i], &route->dst_prefixlen) >= 0);
route->priority = link->network->dhcp_route_metric;
route->table = table;
route->scope = route_scope_from_address(route, &address);
r = route_configure(route, link, dhcp4_route_handler);
if (r < 0)
return log_link_warning_errno(link, r, "Could not set host route: %m");
link->dhcp4_messages++;
}
r = sd_dhcp_lease_get_router(link->dhcp_lease, &gateway);
if (r == -ENODATA)
log_link_info_errno(link, r, "DHCP: No routes received from DHCP server: %m");
else if (r < 0)
log_link_warning_errno(link, r, "DHCP error: could not get gateway: %m");
/* According to RFC 3442: If the DHCP server returns both a Classless Static Routes option and
a Router option, the DHCP client MUST ignore the Router option. */
if (classless_route && static_route)
log_link_warning(link, "Classless static routes received from DHCP server: ignoring static-route option and router option");
if (r >= 0 && !classless_route) {
_cleanup_(route_freep) Route *route = NULL;
_cleanup_(route_freep) Route *route_gw = NULL;
r = route_new(&route);
if (r < 0)
return log_link_error_errno(link, r, "Could not allocate route: %m");
route->protocol = RTPROT_DHCP;
r = route_new(&route_gw);
if (r < 0)
return log_link_error_errno(link, r, "Could not allocate route: %m");
/* The dhcp netmask may mask out the gateway. Add an explicit
* route for the gw host so that we can route no matter the
* netmask or existing kernel route tables. */
route_gw->family = AF_INET;
route_gw->dst.in = gateway;
route_gw->dst_prefixlen = 32;
route_gw->prefsrc.in = address;
route_gw->scope = RT_SCOPE_LINK;
route_gw->protocol = RTPROT_DHCP;
route_gw->priority = link->network->dhcp_route_metric;
route_gw->table = table;
r = route_configure(route_gw, link, dhcp4_route_handler);
if (r < 0)
return log_link_warning_errno(link, r, "Could not set host route: %m");
link->dhcp4_messages++;
route->family = AF_INET;
route->gw.in = gateway;
route->prefsrc.in = address;
route->priority = link->network->dhcp_route_metric;
route->table = table;
r = route_configure(route, link, dhcp4_route_handler);
if (r < 0) {
log_link_warning_errno(link, r, "Could not set routes: %m");
link_enter_failed(link);
return r;
}
link->dhcp4_messages++;
}
return 0;
}
static int dhcp_lease_lost(Link *link) {
_cleanup_(address_freep) Address *address = NULL;
struct in_addr addr;
struct in_addr netmask;
struct in_addr gateway;
unsigned prefixlen = 0;
int r;
assert(link);
assert(link->dhcp_lease);
log_link_warning(link, "DHCP lease lost");
if (link->network->dhcp_use_routes) {
_cleanup_free_ sd_dhcp_route **routes = NULL;
int n, i;
n = sd_dhcp_lease_get_routes(link->dhcp_lease, &routes);
if (n >= 0) {
for (i = 0; i < n; i++) {
_cleanup_(route_freep) Route *route = NULL;
r = route_new(&route);
if (r >= 0) {
route->family = AF_INET;
assert_se(sd_dhcp_route_get_gateway(routes[i], &route->gw.in) >= 0);
assert_se(sd_dhcp_route_get_destination(routes[i], &route->dst.in) >= 0);
assert_se(sd_dhcp_route_get_destination_prefix_length(routes[i], &route->dst_prefixlen) >= 0);
route_remove(route, link,
link_route_remove_handler);
}
}
}
}
r = address_new(&address);
if (r >= 0) {
r = sd_dhcp_lease_get_router(link->dhcp_lease, &gateway);
if (r >= 0) {
_cleanup_(route_freep) Route *route_gw = NULL;
_cleanup_(route_freep) Route *route = NULL;
r = route_new(&route_gw);
if (r >= 0) {
route_gw->family = AF_INET;
route_gw->dst.in = gateway;
route_gw->dst_prefixlen = 32;
route_gw->scope = RT_SCOPE_LINK;
route_remove(route_gw, link,
link_route_remove_handler);
}
r = route_new(&route);
if (r >= 0) {
route->family = AF_INET;
route->gw.in = gateway;
route_remove(route, link,
link_route_remove_handler);
}
}
r = sd_dhcp_lease_get_address(link->dhcp_lease, &addr);
if (r >= 0) {
r = sd_dhcp_lease_get_netmask(link->dhcp_lease, &netmask);
if (r >= 0)
prefixlen = in4_addr_netmask_to_prefixlen(&netmask);
address->family = AF_INET;
address->in_addr.in = addr;
address->prefixlen = prefixlen;
address_remove(address, link, link_address_remove_handler);
}
}
if (link->network->dhcp_use_mtu) {
uint16_t mtu;
r = sd_dhcp_lease_get_mtu(link->dhcp_lease, &mtu);
if (r >= 0 && link->original_mtu != mtu) {
r = link_set_mtu(link, link->original_mtu);
if (r < 0) {
log_link_warning(link,
"DHCP error: could not reset MTU");
link_enter_failed(link);
return r;
}
}
}
if (link->network->dhcp_use_hostname) {
const char *hostname = NULL;
if (link->network->dhcp_hostname)
hostname = link->network->dhcp_hostname;
else
(void) sd_dhcp_lease_get_hostname(link->dhcp_lease, &hostname);
if (hostname) {
/* If a hostname was set due to the lease, then unset it now. */
r = manager_set_hostname(link->manager, NULL);
if (r < 0)
log_link_warning_errno(link, r, "Failed to reset transient hostname: %m");
}
}
link->dhcp_lease = sd_dhcp_lease_unref(link->dhcp_lease);
link_dirty(link);
link->dhcp4_configured = false;
return 0;
}
static int dhcp4_address_handler(sd_netlink *rtnl, sd_netlink_message *m,
void *userdata) {
_cleanup_(link_unrefp) Link *link = userdata;
int r;
assert(link);
r = sd_netlink_message_get_errno(m);
if (r < 0 && r != -EEXIST) {
log_link_error_errno(link, r, "Could not set DHCPv4 address: %m");
link_enter_failed(link);
} else if (r >= 0)
manager_rtnl_process_address(rtnl, m, link->manager);
link_set_dhcp_routes(link);
if (link->dhcp4_messages == 0) {
link->dhcp4_configured = true;
link_check_ready(link);
}
return 1;
}
static int dhcp4_update_address(Link *link,
struct in_addr *address,
struct in_addr *netmask,
uint32_t lifetime) {
_cleanup_(address_freep) Address *addr = NULL;
unsigned prefixlen;
int r;
assert(address);
assert(netmask);
assert(lifetime);
prefixlen = in4_addr_netmask_to_prefixlen(netmask);
r = address_new(&addr);
if (r < 0)
return r;
addr->family = AF_INET;
addr->in_addr.in.s_addr = address->s_addr;
addr->cinfo.ifa_prefered = lifetime;
addr->cinfo.ifa_valid = lifetime;
addr->prefixlen = prefixlen;
addr->broadcast.s_addr = address->s_addr | ~netmask->s_addr;
/* allow reusing an existing address and simply update its lifetime
* in case it already exists */
r = address_configure(addr, link, dhcp4_address_handler, true);
if (r < 0)
return r;
return 0;
}
static int dhcp_lease_renew(sd_dhcp_client *client, Link *link) {
sd_dhcp_lease *lease;
struct in_addr address;
struct in_addr netmask;
uint32_t lifetime = CACHE_INFO_INFINITY_LIFE_TIME;
int r;
assert(link);
assert(client);
assert(link->network);
r = sd_dhcp_client_get_lease(client, &lease);
if (r < 0)
return log_link_warning_errno(link, r, "DHCP error: no lease: %m");
sd_dhcp_lease_unref(link->dhcp_lease);
link->dhcp4_configured = false;
link->dhcp_lease = sd_dhcp_lease_ref(lease);
link_dirty(link);
r = sd_dhcp_lease_get_address(lease, &address);
if (r < 0)
return log_link_warning_errno(link, r, "DHCP error: no address: %m");
r = sd_dhcp_lease_get_netmask(lease, &netmask);
if (r < 0)
return log_link_warning_errno(link, r, "DHCP error: no netmask: %m");
if (!link->network->dhcp_critical) {
r = sd_dhcp_lease_get_lifetime(link->dhcp_lease, &lifetime);
if (r < 0)
return log_link_warning_errno(link, r, "DHCP error: no lifetime: %m");
}
r = dhcp4_update_address(link, &address, &netmask, lifetime);
if (r < 0) {
log_link_warning_errno(link, r, "Could not update IP address: %m");
link_enter_failed(link);
return r;
}
return 0;
}
static int dhcp_lease_acquired(sd_dhcp_client *client, Link *link) {
sd_dhcp_lease *lease;
struct in_addr address;
struct in_addr netmask;
struct in_addr gateway;
unsigned prefixlen;
uint32_t lifetime = CACHE_INFO_INFINITY_LIFE_TIME;
int r;
assert(client);
assert(link);
r = sd_dhcp_client_get_lease(client, &lease);
if (r < 0)
return log_link_error_errno(link, r, "DHCP error: No lease: %m");
r = sd_dhcp_lease_get_address(lease, &address);
if (r < 0)
return log_link_error_errno(link, r, "DHCP error: No address: %m");
r = sd_dhcp_lease_get_netmask(lease, &netmask);
if (r < 0)
return log_link_error_errno(link, r, "DHCP error: No netmask: %m");
prefixlen = in4_addr_netmask_to_prefixlen(&netmask);
r = sd_dhcp_lease_get_router(lease, &gateway);
if (r < 0 && r != -ENODATA)
return log_link_error_errno(link, r, "DHCP error: Could not get gateway: %m");
if (r >= 0)
log_struct(LOG_INFO,
LOG_LINK_INTERFACE(link),
LOG_LINK_MESSAGE(link, "DHCPv4 address %u.%u.%u.%u/%u via %u.%u.%u.%u",
ADDRESS_FMT_VAL(address),
prefixlen,
ADDRESS_FMT_VAL(gateway)),
"ADDRESS=%u.%u.%u.%u", ADDRESS_FMT_VAL(address),
"PREFIXLEN=%u", prefixlen,
"GATEWAY=%u.%u.%u.%u", ADDRESS_FMT_VAL(gateway));
else
log_struct(LOG_INFO,
LOG_LINK_INTERFACE(link),
LOG_LINK_MESSAGE(link, "DHCPv4 address %u.%u.%u.%u/%u",
ADDRESS_FMT_VAL(address),
prefixlen),
"ADDRESS=%u.%u.%u.%u", ADDRESS_FMT_VAL(address),
"PREFIXLEN=%u", prefixlen);
link->dhcp_lease = sd_dhcp_lease_ref(lease);
link_dirty(link);
if (link->network->dhcp_use_mtu) {
uint16_t mtu;
r = sd_dhcp_lease_get_mtu(lease, &mtu);
if (r >= 0) {
r = link_set_mtu(link, mtu);
if (r < 0)
log_link_error_errno(link, r, "Failed to set MTU to %" PRIu16 ": %m", mtu);
}
}
if (link->network->dhcp_use_hostname) {
const char *dhcpname = NULL;
_cleanup_free_ char *hostname = NULL;
if (link->network->dhcp_hostname)
dhcpname = link->network->dhcp_hostname;
else
(void) sd_dhcp_lease_get_hostname(lease, &dhcpname);
if (dhcpname) {
r = shorten_overlong(dhcpname, &hostname);
if (r < 0)
log_link_warning_errno(link, r, "Unable to shorten overlong DHCP hostname '%s', ignoring: %m", dhcpname);
if (r == 1)
log_link_notice(link, "Overlong DCHP hostname received, shortened from '%s' to '%s'", dhcpname, hostname);
}
if (hostname) {
r = manager_set_hostname(link->manager, hostname);
if (r < 0)
log_link_error_errno(link, r, "Failed to set transient hostname to '%s': %m", hostname);
}
}
if (link->network->dhcp_use_timezone) {
const char *tz = NULL;
(void) sd_dhcp_lease_get_timezone(link->dhcp_lease, &tz);
if (tz) {
r = manager_set_timezone(link->manager, tz);
if (r < 0)
log_link_error_errno(link, r, "Failed to set timezone to '%s': %m", tz);
}
}
if (!link->network->dhcp_critical) {
r = sd_dhcp_lease_get_lifetime(link->dhcp_lease, &lifetime);
if (r < 0) {
log_link_warning_errno(link, r, "DHCP error: no lifetime: %m");
return r;
}
}
r = dhcp4_update_address(link, &address, &netmask, lifetime);
if (r < 0) {
log_link_warning_errno(link, r, "Could not update IP address: %m");
link_enter_failed(link);
return r;
}
return 0;
}
static void dhcp4_handler(sd_dhcp_client *client, int event, void *userdata) {
Link *link = userdata;
int r = 0;
assert(link);
assert(link->network);
assert(link->manager);
if (IN_SET(link->state, LINK_STATE_FAILED, LINK_STATE_LINGER))
return;
switch (event) {
case SD_DHCP_CLIENT_EVENT_EXPIRED:
case SD_DHCP_CLIENT_EVENT_STOP:
case SD_DHCP_CLIENT_EVENT_IP_CHANGE:
if (link->network->dhcp_critical) {
log_link_error(link, "DHCPv4 connection considered system critical, ignoring request to reconfigure it.");
return;
}
if (link->dhcp_lease) {
r = dhcp_lease_lost(link);
if (r < 0) {
link_enter_failed(link);
return;
}
}
if (event == SD_DHCP_CLIENT_EVENT_IP_CHANGE) {
r = dhcp_lease_acquired(client, link);
if (r < 0) {
link_enter_failed(link);
return;
}
}
break;
case SD_DHCP_CLIENT_EVENT_RENEW:
r = dhcp_lease_renew(client, link);
if (r < 0) {
link_enter_failed(link);
return;
}
break;
case SD_DHCP_CLIENT_EVENT_IP_ACQUIRE:
r = dhcp_lease_acquired(client, link);
if (r < 0) {
link_enter_failed(link);
return;
}
break;
default:
if (event < 0)
log_link_warning_errno(link, event, "DHCP error: Client failed: %m");
else
log_link_warning(link, "DHCP unknown event: %i", event);
break;
}
return;
}
static int dhcp4_set_hostname(Link *link) {
_cleanup_free_ char *hostname = NULL;
const char *hn;
int r;
assert(link);
if (!link->network->dhcp_send_hostname)
hn = NULL;
else if (link->network->dhcp_hostname)
hn = link->network->dhcp_hostname;
else {
r = gethostname_strict(&hostname);
if (r < 0 && r != -ENXIO) /* ENXIO: no hostname set or hostname is "localhost" */
return r;
hn = hostname;
}
return sd_dhcp_client_set_hostname(link->dhcp_client, hn);
}
static bool promote_secondaries_enabled(const char *ifname) {
_cleanup_free_ char *promote_secondaries_sysctl = NULL;
char *promote_secondaries_path;
int r;
promote_secondaries_path = strjoina("net/ipv4/conf/", ifname, "/promote_secondaries");
r = sysctl_read(promote_secondaries_path, &promote_secondaries_sysctl);
if (r < 0) {
log_debug_errno(r, "Cannot read sysctl %s", promote_secondaries_path);
return false;
}
truncate_nl(promote_secondaries_sysctl);
r = parse_boolean(promote_secondaries_sysctl);
if (r < 0)
log_warning_errno(r, "Cannot parse sysctl %s with content %s as boolean", promote_secondaries_path, promote_secondaries_sysctl);
return r > 0;
}
/* dhcp4_set_promote_secondaries will ensure this interface has
* the "promote_secondaries" option in the kernel set. If this sysctl
* is not set DHCP will work only as long as the IP address does not
* changes between leases. The kernel will remove all secondary IP
* addresses of an interface otherwise. The way systemd-network works
* is that the new IP of a lease is added as a secondary IP and when
* the primary one expires it relies on the kernel to promote the
* secondary IP. See also https://github.com/systemd/systemd/issues/7163
*/
int dhcp4_set_promote_secondaries(Link *link) {
int r;
assert(link);
assert(link->network);
assert(link->network->dhcp & ADDRESS_FAMILY_IPV4);
/* check if the kernel has promote_secondaries enabled for our
* interface. If it is not globally enabled or enabled for the
* specific interface we must either enable it.
*/
if (!(promote_secondaries_enabled("all") || promote_secondaries_enabled(link->ifname))) {
char *promote_secondaries_path = NULL;
log_link_debug(link, "promote_secondaries is unset, setting it");
promote_secondaries_path = strjoina("net/ipv4/conf/", link->ifname, "/promote_secondaries");
r = sysctl_write(promote_secondaries_path, "1");
if (r < 0)
log_link_warning_errno(link, r, "cannot set sysctl %s to 1", promote_secondaries_path);
return r > 0;
}
return 0;
}
int dhcp4_configure(Link *link) {
int r;
assert(link);
assert(link->network);
assert(link->network->dhcp & ADDRESS_FAMILY_IPV4);
if (!link->dhcp_client) {
r = sd_dhcp_client_new(&link->dhcp_client, link->network->dhcp_anonymize);
if (r < 0)
return r;
}
r = sd_dhcp_client_attach_event(link->dhcp_client, NULL, 0);
if (r < 0)
return r;
r = sd_dhcp_client_set_mac(link->dhcp_client,
(const uint8_t *) &link->mac,
sizeof (link->mac), ARPHRD_ETHER);
if (r < 0)
return r;
r = sd_dhcp_client_set_ifindex(link->dhcp_client, link->ifindex);
if (r < 0)
return r;
r = sd_dhcp_client_set_callback(link->dhcp_client, dhcp4_handler, link);
if (r < 0)
return r;
r = sd_dhcp_client_set_request_broadcast(link->dhcp_client,
link->network->dhcp_broadcast);
if (r < 0)
return r;
if (link->mtu) {
r = sd_dhcp_client_set_mtu(link->dhcp_client, link->mtu);
if (r < 0)
return r;
}
if (link->network->dhcp_use_mtu) {
r = sd_dhcp_client_set_request_option(link->dhcp_client,
SD_DHCP_OPTION_INTERFACE_MTU);
if (r < 0)
return r;
}
/* NOTE: even if this variable is called "use", it also "sends" PRL
* options, maybe there should be a different configuration variable
* to send or not route options?. */
/* NOTE: when using Anonymize=yes, routes PRL options are sent
* by default, so they don't need to be added here. */
if (link->network->dhcp_use_routes && !link->network->dhcp_anonymize) {
r = sd_dhcp_client_set_request_option(link->dhcp_client,
SD_DHCP_OPTION_STATIC_ROUTE);
if (r < 0)
return r;
r = sd_dhcp_client_set_request_option(link->dhcp_client,
SD_DHCP_OPTION_CLASSLESS_STATIC_ROUTE);
if (r < 0)
return r;
}
if (link->network->dhcp_use_ntp) {
r = sd_dhcp_client_set_request_option(link->dhcp_client, SD_DHCP_OPTION_NTP_SERVER);
if (r < 0)
return r;
}
if (link->network->dhcp_use_timezone) {
r = sd_dhcp_client_set_request_option(link->dhcp_client, SD_DHCP_OPTION_NEW_TZDB_TIMEZONE);
if (r < 0)
return r;
}
r = dhcp4_set_hostname(link);
if (r < 0)
return r;
if (link->network->dhcp_vendor_class_identifier) {
r = sd_dhcp_client_set_vendor_class_identifier(link->dhcp_client,
link->network->dhcp_vendor_class_identifier);
if (r < 0)
return r;
}
if (link->network->dhcp_user_class) {
r = sd_dhcp_client_set_user_class(link->dhcp_client, (const char **) link->network->dhcp_user_class);
if (r < 0)
return r;
}
if (link->network->dhcp_client_port) {
r = sd_dhcp_client_set_client_port(link->dhcp_client, link->network->dhcp_client_port);
if (r < 0)
return r;
}
switch (link->network->dhcp_client_identifier) {
case DHCP_CLIENT_ID_DUID: {
/* If configured, apply user specified DUID and/or IAID */
const DUID *duid = link_duid(link);
r = sd_dhcp_client_set_iaid_duid(link->dhcp_client,
link->network->iaid,
duid->type,
duid->raw_data_len > 0 ? duid->raw_data : NULL,
duid->raw_data_len);
if (r < 0)
return r;
break;
}
case DHCP_CLIENT_ID_DUID_ONLY: {
/* If configured, apply user specified DUID */
const DUID *duid = link_duid(link);
r = sd_dhcp_client_set_duid(link->dhcp_client,
duid->type,
duid->raw_data_len > 0 ? duid->raw_data : NULL,
duid->raw_data_len);
if (r < 0)
return r;
break;
}
case DHCP_CLIENT_ID_MAC:
r = sd_dhcp_client_set_client_id(link->dhcp_client,
ARPHRD_ETHER,
(const uint8_t *) &link->mac,
sizeof(link->mac));
if (r < 0)
return r;
break;
default:
assert_not_reached("Unknown client identifier type.");
}
return 0;
}