1 /* SPDX-License-Identifier: LGPL-2.1-or-later */
3 #include <netinet/in.h>
4 #include <linux/if_arp.h>
7 #include "sd-dhcp-server.h"
11 #include "networkd-address.h"
12 #include "networkd-dhcp-server-bus.h"
13 #include "networkd-dhcp-server-static-lease.h"
14 #include "networkd-dhcp-server.h"
15 #include "networkd-link.h"
16 #include "networkd-manager.h"
17 #include "networkd-network.h"
18 #include "networkd-queue.h"
19 #include "networkd-route-util.h"
20 #include "parse-util.h"
21 #include "socket-netlink.h"
22 #include "string-table.h"
23 #include "string-util.h"
26 static bool link_dhcp4_server_enabled(Link
*link
) {
29 if (link
->flags
& IFF_LOOPBACK
)
35 if (link
->iftype
== ARPHRD_CAN
)
38 return link
->network
->dhcp_server
;
41 void network_adjust_dhcp_server(Network
*network
) {
44 if (!network
->dhcp_server
)
48 log_warning("%s: DHCPServer= is enabled for bond slave. Disabling DHCP server.",
50 network
->dhcp_server
= false;
54 if (!in4_addr_is_set(&network
->dhcp_server_address
)) {
58 ORDERED_HASHMAP_FOREACH(address
, network
->addresses_by_section
) {
59 if (section_is_invalid(address
->section
))
62 if (address
->family
!= AF_INET
)
65 if (in4_addr_is_localhost(&address
->in_addr
.in
))
68 if (in4_addr_is_link_local(&address
->in_addr
.in
))
71 if (in4_addr_is_set(&address
->in_addr_peer
.in
))
78 log_warning("%s: DHCPServer= is enabled, but no static address configured. "
79 "Disabling DHCP server.",
81 network
->dhcp_server
= false;
87 int link_request_dhcp_server_address(Link
*link
) {
88 _cleanup_(address_freep
) Address
*address
= NULL
;
93 assert(link
->network
);
95 if (!link_dhcp4_server_enabled(link
))
98 if (!in4_addr_is_set(&link
->network
->dhcp_server_address
))
101 r
= address_new(&address
);
105 address
->source
= NETWORK_CONFIG_SOURCE_STATIC
;
106 address
->family
= AF_INET
;
107 address
->in_addr
.in
= link
->network
->dhcp_server_address
;
108 address
->prefixlen
= link
->network
->dhcp_server_address_prefixlen
;
109 address_set_broadcast(address
, link
);
111 if (address_get(link
, address
, &existing
) >= 0 &&
112 address_exists(existing
) &&
113 existing
->source
== NETWORK_CONFIG_SOURCE_STATIC
)
114 /* The same address seems explicitly configured in [Address] or [Network] section.
115 * Configure the DHCP server address only when it is not. */
118 return link_request_static_address(link
, TAKE_PTR(address
), true);
121 static int link_find_dhcp_server_address(Link
*link
, Address
**ret
) {
125 assert(link
->network
);
127 /* If ServerAddress= is specified, then use the address. */
128 if (in4_addr_is_set(&link
->network
->dhcp_server_address
))
129 return link_get_ipv4_address(link
, &link
->network
->dhcp_server_address
,
130 link
->network
->dhcp_server_address_prefixlen
, ret
);
132 /* If not, then select one from static addresses. */
133 SET_FOREACH(address
, link
->addresses
) {
134 if (address
->source
!= NETWORK_CONFIG_SOURCE_STATIC
)
136 if (!address_exists(address
))
138 if (address
->family
!= AF_INET
)
140 if (in4_addr_is_localhost(&address
->in_addr
.in
))
142 if (in4_addr_is_link_local(&address
->in_addr
.in
))
144 if (in4_addr_is_set(&address
->in_addr_peer
.in
))
154 static int dhcp_server_find_uplink(Link
*link
, Link
**ret
) {
157 if (link
->network
->dhcp_server_uplink_name
)
158 return link_get_by_name(link
->manager
, link
->network
->dhcp_server_uplink_name
, ret
);
160 if (link
->network
->dhcp_server_uplink_index
> 0)
161 return link_get_by_index(link
->manager
, link
->network
->dhcp_server_uplink_index
, ret
);
163 if (link
->network
->dhcp_server_uplink_index
== UPLINK_INDEX_AUTO
) {
164 /* It is not necessary to propagate error in automatic selection. */
165 if (manager_find_uplink(link
->manager
, AF_INET
, link
, ret
) < 0)
174 static int link_push_uplink_to_dhcp_server(
176 sd_dhcp_lease_server_type_t what
,
179 _cleanup_free_
struct in_addr
*addresses
= NULL
;
180 bool use_dhcp_lease_data
= true;
181 size_t n_addresses
= 0;
187 assert(link
->network
);
189 log_link_debug(link
, "Copying %s from link", dhcp_lease_server_type_to_string(what
));
193 case SD_DHCP_LEASE_DNS
:
194 /* For DNS we have a special case. We the data configured explicitly locally along with the
195 * data from the DHCP lease. */
197 for (unsigned i
= 0; i
< link
->network
->n_dns
; i
++) {
200 /* Only look for IPv4 addresses */
201 if (link
->network
->dns
[i
]->family
!= AF_INET
)
204 ia
= link
->network
->dns
[i
]->address
.in
;
206 /* Never propagate obviously borked data */
207 if (in4_addr_is_null(&ia
) || in4_addr_is_localhost(&ia
))
210 if (!GREEDY_REALLOC(addresses
, n_addresses
+ 1))
213 addresses
[n_addresses
++] = ia
;
216 use_dhcp_lease_data
= link
->network
->dhcp_use_dns
;
219 case SD_DHCP_LEASE_NTP
: {
222 /* For NTP things are similar, but for NTP hostnames can be configured too, which we cannot
223 * propagate via DHCP. Hence let's only propagate those which are IP addresses. */
225 STRV_FOREACH(i
, link
->network
->ntp
) {
226 union in_addr_union ia
;
228 if (in_addr_from_string(AF_INET
, *i
, &ia
) < 0)
231 /* Never propagate obviously borked data */
232 if (in4_addr_is_null(&ia
.in
) || in4_addr_is_localhost(&ia
.in
))
235 if (!GREEDY_REALLOC(addresses
, n_addresses
+ 1))
238 addresses
[n_addresses
++] = ia
.in
;
241 use_dhcp_lease_data
= link
->network
->dhcp_use_ntp
;
245 case SD_DHCP_LEASE_SIP
:
247 /* For SIP we don't allow explicit, local configuration, but there's control whether to use the data */
248 use_dhcp_lease_data
= link
->network
->dhcp_use_sip
;
251 case SD_DHCP_LEASE_POP3
:
252 case SD_DHCP_LEASE_SMTP
:
253 case SD_DHCP_LEASE_LPR
:
254 /* For the other server types we currently do not allow local configuration of server data,
255 * since there are typically no local consumers of the data. */
259 assert_not_reached();
262 if (use_dhcp_lease_data
&& link
->dhcp_lease
) {
263 const struct in_addr
*da
;
265 int n
= sd_dhcp_lease_get_servers(link
->dhcp_lease
, what
, &da
);
267 if (!GREEDY_REALLOC(addresses
, n_addresses
+ n
))
270 for (int j
= 0; j
< n
; j
++)
271 if (in4_addr_is_non_local(&da
[j
]))
272 addresses
[n_addresses
++] = da
[j
];
276 if (n_addresses
<= 0)
279 return sd_dhcp_server_set_servers(s
, what
, addresses
, n_addresses
);
282 static int dhcp4_server_parse_dns_server_string_and_warn(
284 struct in_addr
**addresses
,
285 size_t *n_addresses
) {
288 _cleanup_free_
char *word
= NULL
, *server_name
= NULL
;
289 union in_addr_union address
;
290 int family
, r
, ifindex
= 0;
292 r
= extract_first_word(&string
, &word
, NULL
, 0);
298 r
= in_addr_ifindex_name_from_string_auto(word
, &family
, &address
, &ifindex
, &server_name
);
300 log_warning_errno(r
, "Failed to parse DNS server address '%s', ignoring: %m", word
);
304 /* Only look for IPv4 addresses */
305 if (family
!= AF_INET
)
308 /* Never propagate obviously borked data */
309 if (in4_addr_is_null(&address
.in
) || in4_addr_is_localhost(&address
.in
))
312 if (!GREEDY_REALLOC(*addresses
, *n_addresses
+ 1))
315 (*addresses
)[(*n_addresses
)++] = address
.in
;
321 static int dhcp4_server_set_dns_from_resolve_conf(Link
*link
) {
322 _cleanup_free_
struct in_addr
*addresses
= NULL
;
323 _cleanup_fclose_
FILE *f
= NULL
;
324 size_t n_addresses
= 0;
327 f
= fopen(PRIVATE_UPLINK_RESOLV_CONF
, "re");
332 return log_warning_errno(errno
, "Failed to open " PRIVATE_UPLINK_RESOLV_CONF
": %m");
336 _cleanup_free_
char *line
= NULL
;
340 r
= read_line(f
, LONG_LINE_MAX
, &line
);
342 return log_error_errno(r
, "Failed to read " PRIVATE_UPLINK_RESOLV_CONF
": %m");
349 if (IN_SET(*l
, '#', ';', 0))
352 a
= first_word(l
, "nameserver");
356 r
= dhcp4_server_parse_dns_server_string_and_warn(a
, &addresses
, &n_addresses
);
358 log_warning_errno(r
, "Failed to parse DNS server address '%s', ignoring.", a
);
361 if (n_addresses
<= 0)
364 return sd_dhcp_server_set_dns(link
->dhcp_server
, addresses
, n_addresses
);
367 static int dhcp4_server_configure(Link
*link
) {
368 bool acquired_uplink
= false;
370 DHCPStaticLease
*static_lease
;
373 bool bind_to_interface
;
378 log_link_debug(link
, "Configuring DHCP Server.");
380 if (link
->dhcp_server
)
383 r
= sd_dhcp_server_new(&link
->dhcp_server
, link
->ifindex
);
387 r
= sd_dhcp_server_attach_event(link
->dhcp_server
, link
->manager
->event
, 0);
391 r
= sd_dhcp_server_set_callback(link
->dhcp_server
, dhcp_server_callback
, link
);
393 return log_link_warning_errno(link
, r
, "Failed to set callback for DHCPv4 server instance: %m");
395 r
= link_find_dhcp_server_address(link
, &address
);
397 return log_link_error_errno(link
, r
, "Failed to find suitable address for DHCPv4 server instance: %m");
399 /* use the server address' subnet as the pool */
400 r
= sd_dhcp_server_configure_pool(link
->dhcp_server
, &address
->in_addr
.in
, address
->prefixlen
,
401 link
->network
->dhcp_server_pool_offset
, link
->network
->dhcp_server_pool_size
);
403 return log_link_error_errno(link
, r
, "Failed to configure address pool for DHCPv4 server instance: %m");
405 if (link
->network
->dhcp_server_max_lease_time_usec
> 0) {
406 r
= sd_dhcp_server_set_max_lease_time(link
->dhcp_server
,
407 DIV_ROUND_UP(link
->network
->dhcp_server_max_lease_time_usec
, USEC_PER_SEC
));
409 return log_link_error_errno(link
, r
, "Failed to set maximum lease time for DHCPv4 server instance: %m");
412 if (link
->network
->dhcp_server_default_lease_time_usec
> 0) {
413 r
= sd_dhcp_server_set_default_lease_time(link
->dhcp_server
,
414 DIV_ROUND_UP(link
->network
->dhcp_server_default_lease_time_usec
, USEC_PER_SEC
));
416 return log_link_error_errno(link
, r
, "Failed to set default lease time for DHCPv4 server instance: %m");
419 r
= sd_dhcp_server_set_next_server(link
->dhcp_server
, &link
->network
->dhcp_server_next_server
);
421 return log_link_warning_errno(link
, r
, "Failed to set next server for DHCPv4 server instance: %m");
423 r
= sd_dhcp_server_set_filename(link
->dhcp_server
, link
->network
->dhcp_server_filename
);
425 return log_link_warning_errno(link
, r
, "Failed to set filename for DHCPv4 server instance: %m");
427 for (sd_dhcp_lease_server_type_t type
= 0; type
< _SD_DHCP_LEASE_SERVER_TYPE_MAX
; type
++) {
429 if (!link
->network
->dhcp_server_emit
[type
].emit
)
432 if (link
->network
->dhcp_server_emit
[type
].n_addresses
> 0)
433 /* Explicitly specified servers to emit */
434 r
= sd_dhcp_server_set_servers(
437 link
->network
->dhcp_server_emit
[type
].addresses
,
438 link
->network
->dhcp_server_emit
[type
].n_addresses
);
440 /* Emission is requested, but nothing explicitly configured. Let's find a suitable upling */
441 if (!acquired_uplink
) {
442 (void) dhcp_server_find_uplink(link
, &uplink
);
443 acquired_uplink
= true;
446 if (uplink
&& uplink
->network
)
447 r
= link_push_uplink_to_dhcp_server(uplink
, type
, link
->dhcp_server
);
448 else if (type
== SD_DHCP_LEASE_DNS
)
449 r
= dhcp4_server_set_dns_from_resolve_conf(link
);
452 "Not emitting %s on link, couldn't find suitable uplink.",
453 dhcp_lease_server_type_to_string(type
));
459 log_link_warning_errno(link
, r
,
460 "Failed to set %s for DHCP server, ignoring: %m",
461 dhcp_lease_server_type_to_string(type
));
464 if (link
->network
->dhcp_server_emit_router
) {
465 r
= sd_dhcp_server_set_router(link
->dhcp_server
, &link
->network
->dhcp_server_router
);
467 return log_link_error_errno(link
, r
, "Failed to set router address for DHCP server: %m");
470 r
= sd_dhcp_server_set_relay_target(link
->dhcp_server
, &link
->network
->dhcp_server_relay_target
);
472 return log_link_error_errno(link
, r
, "Failed to set relay target for DHCP server: %m");
474 bind_to_interface
= sd_dhcp_server_is_in_relay_mode(link
->dhcp_server
) ? false : link
->network
->dhcp_server_bind_to_interface
;
475 r
= sd_dhcp_server_set_bind_to_interface(link
->dhcp_server
, bind_to_interface
);
477 return log_link_error_errno(link
, r
, "Failed to set interface binding for DHCP server: %m");
479 r
= sd_dhcp_server_set_relay_agent_information(link
->dhcp_server
, link
->network
->dhcp_server_relay_agent_circuit_id
, link
->network
->dhcp_server_relay_agent_remote_id
);
481 return log_link_error_errno(link
, r
, "Failed to set agent circuit/remote id for DHCP server: %m");
483 if (link
->network
->dhcp_server_emit_timezone
) {
484 _cleanup_free_
char *buffer
= NULL
;
485 const char *tz
= NULL
;
487 if (link
->network
->dhcp_server_timezone
)
488 tz
= link
->network
->dhcp_server_timezone
;
490 r
= get_timezone(&buffer
);
492 log_link_warning_errno(link
, r
, "Failed to determine timezone, not sending timezone: %m");
498 r
= sd_dhcp_server_set_timezone(link
->dhcp_server
, tz
);
500 return log_link_error_errno(link
, r
, "Failed to set timezone for DHCP server: %m");
504 ORDERED_HASHMAP_FOREACH(p
, link
->network
->dhcp_server_send_options
) {
505 r
= sd_dhcp_server_add_option(link
->dhcp_server
, p
);
509 return log_link_error_errno(link
, r
, "Failed to set DHCPv4 option: %m");
512 ORDERED_HASHMAP_FOREACH(p
, link
->network
->dhcp_server_send_vendor_options
) {
513 r
= sd_dhcp_server_add_vendor_option(link
->dhcp_server
, p
);
517 return log_link_error_errno(link
, r
, "Failed to set DHCPv4 option: %m");
520 HASHMAP_FOREACH(static_lease
, link
->network
->dhcp_static_leases_by_section
) {
521 r
= sd_dhcp_server_set_static_lease(link
->dhcp_server
, &static_lease
->address
, static_lease
->client_id
, static_lease
->client_id_size
);
523 return log_link_error_errno(link
, r
, "Failed to set DHCPv4 static lease for DHCP server: %m");
526 r
= sd_dhcp_server_start(link
->dhcp_server
);
528 return log_link_error_errno(link
, r
, "Could not start DHCPv4 server instance: %m");
530 log_link_debug(link
, "Offering DHCPv4 leases");
535 int link_request_dhcp_server(Link
*link
) {
538 if (!link_dhcp4_server_enabled(link
))
541 if (link
->dhcp_server
)
544 log_link_debug(link
, "Requesting DHCP server.");
545 return link_queue_request(link
, REQUEST_TYPE_DHCP_SERVER
, NULL
, false, NULL
, NULL
, NULL
);
548 static bool dhcp_server_is_ready_to_configure(Link
*link
) {
557 if (!IN_SET(link
->state
, LINK_STATE_CONFIGURING
, LINK_STATE_CONFIGURED
))
560 if (link
->set_flags_messages
> 0)
563 if (!link_has_carrier(link
))
566 if (!link
->static_addresses_configured
)
569 if (link_find_dhcp_server_address(link
, &a
) < 0)
572 if (!address_is_ready(a
))
575 if (dhcp_server_find_uplink(link
, &uplink
) < 0)
578 if (uplink
&& !uplink
->network
)
584 int request_process_dhcp_server(Request
*req
) {
587 assert(req
->type
== REQUEST_TYPE_DHCP_SERVER
);
589 if (!dhcp_server_is_ready_to_configure(req
->link
))
592 return dhcp4_server_configure(req
->link
);
595 int config_parse_dhcp_server_relay_agent_suboption(
597 const char *filename
,
600 unsigned section_line
,
607 char **suboption_value
= data
;
614 if (isempty(rvalue
)) {
615 *suboption_value
= mfree(*suboption_value
);
619 p
= startswith(rvalue
, "string:");
621 log_syntax(unit
, LOG_WARNING
, filename
, line
, 0,
622 "Failed to parse %s=%s'. Invalid format, ignoring.", lvalue
, rvalue
);
625 return free_and_strdup(suboption_value
, empty_to_null(p
));
628 int config_parse_dhcp_server_emit(
630 const char *filename
,
633 unsigned section_line
,
640 NetworkDHCPServerEmitAddress
*emit
= data
;
645 if (isempty(rvalue
)) {
646 emit
->addresses
= mfree(emit
->addresses
);
647 emit
->n_addresses
= 0;
651 for (const char *p
= rvalue
;;) {
652 _cleanup_free_
char *w
= NULL
;
653 union in_addr_union a
;
656 r
= extract_first_word(&p
, &w
, NULL
, 0);
660 log_syntax(unit
, LOG_WARNING
, filename
, line
, r
,
661 "Failed to extract word, ignoring: %s", rvalue
);
667 if (streq(w
, "_server_address"))
668 a
= IN_ADDR_NULL
; /* null address will be converted to the server address. */
670 r
= in_addr_from_string(AF_INET
, w
, &a
);
672 log_syntax(unit
, LOG_WARNING
, filename
, line
, r
,
673 "Failed to parse %s= address '%s', ignoring: %m", lvalue
, w
);
677 if (in4_addr_is_null(&a
.in
)) {
678 log_syntax(unit
, LOG_WARNING
, filename
, line
, 0,
679 "Found a null address in %s=, ignoring.", lvalue
);
684 if (!GREEDY_REALLOC(emit
->addresses
, emit
->n_addresses
+ 1))
687 emit
->addresses
[emit
->n_addresses
++] = a
.in
;
691 int config_parse_dhcp_server_address(
693 const char *filename
,
696 unsigned section_line
,
703 Network
*network
= userdata
;
704 union in_addr_union a
;
705 unsigned char prefixlen
;
712 if (isempty(rvalue
)) {
713 network
->dhcp_server_address
= (struct in_addr
) {};
714 network
->dhcp_server_address_prefixlen
= 0;
718 r
= in_addr_prefix_from_string(rvalue
, AF_INET
, &a
, &prefixlen
);
720 log_syntax(unit
, LOG_WARNING
, filename
, line
, r
,
721 "Failed to parse %s=, ignoring assignment: %s", lvalue
, rvalue
);
724 if (in4_addr_is_null(&a
.in
) || in4_addr_is_localhost(&a
.in
)) {
725 log_syntax(unit
, LOG_WARNING
, filename
, line
, 0,
726 "DHCP server address cannot be the ANY address or a localhost address, "
727 "ignoring assignment: %s", rvalue
);
731 network
->dhcp_server_address
= a
.in
;
732 network
->dhcp_server_address_prefixlen
= prefixlen
;