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
))
61 if (address
->family
== AF_INET
&&
62 !in4_addr_is_localhost(&address
->in_addr
.in
) &&
63 in4_addr_is_null(&address
->in_addr_peer
.in
)) {
69 log_warning("%s: DHCPServer= is enabled, but no static address configured. "
70 "Disabling DHCP server.",
72 network
->dhcp_server
= false;
78 int link_request_dhcp_server_address(Link
*link
) {
79 _cleanup_(address_freep
) Address
*address
= NULL
;
84 assert(link
->network
);
86 if (!link_dhcp4_server_enabled(link
))
89 if (!in4_addr_is_set(&link
->network
->dhcp_server_address
))
92 r
= address_new(&address
);
96 address
->source
= NETWORK_CONFIG_SOURCE_STATIC
;
97 address
->family
= AF_INET
;
98 address
->in_addr
.in
= link
->network
->dhcp_server_address
;
99 address
->prefixlen
= link
->network
->dhcp_server_address_prefixlen
;
100 address_set_broadcast(address
);
102 if (address_get(link
, address
, &existing
) >= 0 &&
103 address_exists(existing
) &&
104 existing
->source
== NETWORK_CONFIG_SOURCE_STATIC
)
105 /* The same address seems explicitly configured in [Address] or [Network] section.
106 * Configure the DHCP server address only when it is not. */
109 return link_request_static_address(link
, TAKE_PTR(address
), true);
112 static int link_find_dhcp_server_address(Link
*link
, Address
**ret
) {
116 assert(link
->network
);
118 /* If ServerAddress= is specified, then use the address. */
119 if (in4_addr_is_set(&link
->network
->dhcp_server_address
))
120 return link_get_ipv4_address(link
, &link
->network
->dhcp_server_address
,
121 link
->network
->dhcp_server_address_prefixlen
, ret
);
123 /* If not, then select one from static addresses. */
124 SET_FOREACH(address
, link
->addresses
) {
125 if (address
->source
!= NETWORK_CONFIG_SOURCE_STATIC
)
127 if (!address_exists(address
))
129 if (address
->family
!= AF_INET
)
131 if (in4_addr_is_localhost(&address
->in_addr
.in
))
133 if (in4_addr_is_set(&address
->in_addr_peer
.in
))
143 static int dhcp_server_find_uplink(Link
*link
, Link
**ret
) {
146 if (link
->network
->dhcp_server_uplink_name
)
147 return link_get_by_name(link
->manager
, link
->network
->dhcp_server_uplink_name
, ret
);
149 if (link
->network
->dhcp_server_uplink_index
> 0)
150 return link_get_by_index(link
->manager
, link
->network
->dhcp_server_uplink_index
, ret
);
152 if (link
->network
->dhcp_server_uplink_index
== UPLINK_INDEX_AUTO
) {
153 /* It is not necessary to propagate error in automatic selection. */
154 if (manager_find_uplink(link
->manager
, AF_INET
, link
, ret
) < 0)
163 static int link_push_uplink_to_dhcp_server(
165 sd_dhcp_lease_server_type_t what
,
168 _cleanup_free_
struct in_addr
*addresses
= NULL
;
169 bool use_dhcp_lease_data
= true;
170 size_t n_addresses
= 0;
176 assert(link
->network
);
178 log_link_debug(link
, "Copying %s from link", dhcp_lease_server_type_to_string(what
));
182 case SD_DHCP_LEASE_DNS
:
183 /* For DNS we have a special case. We the data configured explicitly locally along with the
184 * data from the DHCP lease. */
186 for (unsigned i
= 0; i
< link
->network
->n_dns
; i
++) {
189 /* Only look for IPv4 addresses */
190 if (link
->network
->dns
[i
]->family
!= AF_INET
)
193 ia
= link
->network
->dns
[i
]->address
.in
;
195 /* Never propagate obviously borked data */
196 if (in4_addr_is_null(&ia
) || in4_addr_is_localhost(&ia
))
199 if (!GREEDY_REALLOC(addresses
, n_addresses
+ 1))
202 addresses
[n_addresses
++] = ia
;
205 use_dhcp_lease_data
= link
->network
->dhcp_use_dns
;
208 case SD_DHCP_LEASE_NTP
: {
211 /* For NTP things are similar, but for NTP hostnames can be configured too, which we cannot
212 * propagate via DHCP. Hence let's only propagate those which are IP addresses. */
214 STRV_FOREACH(i
, link
->network
->ntp
) {
215 union in_addr_union ia
;
217 if (in_addr_from_string(AF_INET
, *i
, &ia
) < 0)
220 /* Never propagate obviously borked data */
221 if (in4_addr_is_null(&ia
.in
) || in4_addr_is_localhost(&ia
.in
))
224 if (!GREEDY_REALLOC(addresses
, n_addresses
+ 1))
227 addresses
[n_addresses
++] = ia
.in
;
230 use_dhcp_lease_data
= link
->network
->dhcp_use_ntp
;
234 case SD_DHCP_LEASE_SIP
:
236 /* For SIP we don't allow explicit, local configuration, but there's control whether to use the data */
237 use_dhcp_lease_data
= link
->network
->dhcp_use_sip
;
240 case SD_DHCP_LEASE_POP3
:
241 case SD_DHCP_LEASE_SMTP
:
242 case SD_DHCP_LEASE_LPR
:
243 /* For the other server types we currently do not allow local configuration of server data,
244 * since there are typically no local consumers of the data. */
248 assert_not_reached();
251 if (use_dhcp_lease_data
&& link
->dhcp_lease
) {
252 const struct in_addr
*da
;
254 int n
= sd_dhcp_lease_get_servers(link
->dhcp_lease
, what
, &da
);
256 if (!GREEDY_REALLOC(addresses
, n_addresses
+ n
))
259 for (int j
= 0; j
< n
; j
++)
260 if (in4_addr_is_non_local(&da
[j
]))
261 addresses
[n_addresses
++] = da
[j
];
265 if (n_addresses
<= 0)
268 return sd_dhcp_server_set_servers(s
, what
, addresses
, n_addresses
);
271 static int dhcp4_server_parse_dns_server_string_and_warn(
273 struct in_addr
**addresses
,
274 size_t *n_addresses
) {
277 _cleanup_free_
char *word
= NULL
, *server_name
= NULL
;
278 union in_addr_union address
;
279 int family
, r
, ifindex
= 0;
281 r
= extract_first_word(&string
, &word
, NULL
, 0);
287 r
= in_addr_ifindex_name_from_string_auto(word
, &family
, &address
, &ifindex
, &server_name
);
289 log_warning_errno(r
, "Failed to parse DNS server address '%s', ignoring: %m", word
);
293 /* Only look for IPv4 addresses */
294 if (family
!= AF_INET
)
297 /* Never propagate obviously borked data */
298 if (in4_addr_is_null(&address
.in
) || in4_addr_is_localhost(&address
.in
))
301 if (!GREEDY_REALLOC(*addresses
, *n_addresses
+ 1))
304 (*addresses
)[(*n_addresses
)++] = address
.in
;
310 static int dhcp4_server_set_dns_from_resolve_conf(Link
*link
) {
311 _cleanup_free_
struct in_addr
*addresses
= NULL
;
312 _cleanup_fclose_
FILE *f
= NULL
;
313 size_t n_addresses
= 0;
316 f
= fopen(PRIVATE_UPLINK_RESOLV_CONF
, "re");
321 return log_warning_errno(errno
, "Failed to open " PRIVATE_UPLINK_RESOLV_CONF
": %m");
325 _cleanup_free_
char *line
= NULL
;
329 r
= read_line(f
, LONG_LINE_MAX
, &line
);
331 return log_error_errno(r
, "Failed to read " PRIVATE_UPLINK_RESOLV_CONF
": %m");
338 if (IN_SET(*l
, '#', ';', 0))
341 a
= first_word(l
, "nameserver");
345 r
= dhcp4_server_parse_dns_server_string_and_warn(a
, &addresses
, &n_addresses
);
347 log_warning_errno(r
, "Failed to parse DNS server address '%s', ignoring.", a
);
350 if (n_addresses
<= 0)
353 return sd_dhcp_server_set_dns(link
->dhcp_server
, addresses
, n_addresses
);
356 static int dhcp4_server_configure(Link
*link
) {
357 bool acquired_uplink
= false;
359 DHCPStaticLease
*static_lease
;
362 bool bind_to_interface
;
367 log_link_debug(link
, "Configuring DHCP Server.");
369 if (link
->dhcp_server
)
372 r
= sd_dhcp_server_new(&link
->dhcp_server
, link
->ifindex
);
376 r
= sd_dhcp_server_attach_event(link
->dhcp_server
, link
->manager
->event
, 0);
380 r
= sd_dhcp_server_set_callback(link
->dhcp_server
, dhcp_server_callback
, link
);
382 return log_link_warning_errno(link
, r
, "Failed to set callback for DHCPv4 server instance: %m");
384 r
= link_find_dhcp_server_address(link
, &address
);
386 return log_link_error_errno(link
, r
, "Failed to find suitable address for DHCPv4 server instance: %m");
388 /* use the server address' subnet as the pool */
389 r
= sd_dhcp_server_configure_pool(link
->dhcp_server
, &address
->in_addr
.in
, address
->prefixlen
,
390 link
->network
->dhcp_server_pool_offset
, link
->network
->dhcp_server_pool_size
);
392 return log_link_error_errno(link
, r
, "Failed to configure address pool for DHCPv4 server instance: %m");
394 if (link
->network
->dhcp_server_max_lease_time_usec
> 0) {
395 r
= sd_dhcp_server_set_max_lease_time(link
->dhcp_server
,
396 DIV_ROUND_UP(link
->network
->dhcp_server_max_lease_time_usec
, USEC_PER_SEC
));
398 return log_link_error_errno(link
, r
, "Failed to set maximum lease time for DHCPv4 server instance: %m");
401 if (link
->network
->dhcp_server_default_lease_time_usec
> 0) {
402 r
= sd_dhcp_server_set_default_lease_time(link
->dhcp_server
,
403 DIV_ROUND_UP(link
->network
->dhcp_server_default_lease_time_usec
, USEC_PER_SEC
));
405 return log_link_error_errno(link
, r
, "Failed to set default lease time for DHCPv4 server instance: %m");
408 for (sd_dhcp_lease_server_type_t type
= 0; type
< _SD_DHCP_LEASE_SERVER_TYPE_MAX
; type
++) {
410 if (!link
->network
->dhcp_server_emit
[type
].emit
)
413 if (link
->network
->dhcp_server_emit
[type
].n_addresses
> 0)
414 /* Explicitly specified servers to emit */
415 r
= sd_dhcp_server_set_servers(
418 link
->network
->dhcp_server_emit
[type
].addresses
,
419 link
->network
->dhcp_server_emit
[type
].n_addresses
);
421 /* Emission is requested, but nothing explicitly configured. Let's find a suitable upling */
422 if (!acquired_uplink
) {
423 (void) dhcp_server_find_uplink(link
, &uplink
);
424 acquired_uplink
= true;
427 if (uplink
&& uplink
->network
)
428 r
= link_push_uplink_to_dhcp_server(uplink
, type
, link
->dhcp_server
);
429 else if (type
== SD_DHCP_LEASE_DNS
)
430 r
= dhcp4_server_set_dns_from_resolve_conf(link
);
433 "Not emitting %s on link, couldn't find suitable uplink.",
434 dhcp_lease_server_type_to_string(type
));
440 log_link_warning_errno(link
, r
,
441 "Failed to set %s for DHCP server, ignoring: %m",
442 dhcp_lease_server_type_to_string(type
));
445 if (link
->network
->dhcp_server_emit_router
) {
446 r
= sd_dhcp_server_set_router(link
->dhcp_server
, &link
->network
->dhcp_server_router
);
448 return log_link_error_errno(link
, r
, "Failed to set router address for DHCP server: %m");
451 r
= sd_dhcp_server_set_relay_target(link
->dhcp_server
, &link
->network
->dhcp_server_relay_target
);
453 return log_link_error_errno(link
, r
, "Failed to set relay target for DHCP server: %m");
455 bind_to_interface
= sd_dhcp_server_is_in_relay_mode(link
->dhcp_server
) ? false : link
->network
->dhcp_server_bind_to_interface
;
456 r
= sd_dhcp_server_set_bind_to_interface(link
->dhcp_server
, bind_to_interface
);
458 return log_link_error_errno(link
, r
, "Failed to set interface binding for DHCP server: %m");
460 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
);
462 return log_link_error_errno(link
, r
, "Failed to set agent circuit/remote id for DHCP server: %m");
464 if (link
->network
->dhcp_server_emit_timezone
) {
465 _cleanup_free_
char *buffer
= NULL
;
466 const char *tz
= NULL
;
468 if (link
->network
->dhcp_server_timezone
)
469 tz
= link
->network
->dhcp_server_timezone
;
471 r
= get_timezone(&buffer
);
473 log_link_warning_errno(link
, r
, "Failed to determine timezone, not sending timezone: %m");
479 r
= sd_dhcp_server_set_timezone(link
->dhcp_server
, tz
);
481 return log_link_error_errno(link
, r
, "Failed to set timezone for DHCP server: %m");
485 ORDERED_HASHMAP_FOREACH(p
, link
->network
->dhcp_server_send_options
) {
486 r
= sd_dhcp_server_add_option(link
->dhcp_server
, p
);
490 return log_link_error_errno(link
, r
, "Failed to set DHCPv4 option: %m");
493 ORDERED_HASHMAP_FOREACH(p
, link
->network
->dhcp_server_send_vendor_options
) {
494 r
= sd_dhcp_server_add_vendor_option(link
->dhcp_server
, p
);
498 return log_link_error_errno(link
, r
, "Failed to set DHCPv4 option: %m");
501 HASHMAP_FOREACH(static_lease
, link
->network
->dhcp_static_leases_by_section
) {
502 r
= sd_dhcp_server_set_static_lease(link
->dhcp_server
, &static_lease
->address
, static_lease
->client_id
, static_lease
->client_id_size
);
504 return log_link_error_errno(link
, r
, "Failed to set DHCPv4 static lease for DHCP server: %m");
507 r
= sd_dhcp_server_start(link
->dhcp_server
);
509 return log_link_error_errno(link
, r
, "Could not start DHCPv4 server instance: %m");
511 log_link_debug(link
, "Offering DHCPv4 leases");
516 int link_request_dhcp_server(Link
*link
) {
519 if (!link_dhcp4_server_enabled(link
))
522 if (link
->dhcp_server
)
525 log_link_debug(link
, "Requesting DHCP server.");
526 return link_queue_request(link
, REQUEST_TYPE_DHCP_SERVER
, NULL
, false, NULL
, NULL
, NULL
);
529 static bool dhcp_server_is_ready_to_configure(Link
*link
) {
538 if (!IN_SET(link
->state
, LINK_STATE_CONFIGURING
, LINK_STATE_CONFIGURED
))
541 if (link
->set_flags_messages
> 0)
544 if (!link_has_carrier(link
))
547 if (!link
->static_addresses_configured
)
550 if (link_find_dhcp_server_address(link
, &a
) < 0)
553 if (!address_is_ready(a
))
556 if (dhcp_server_find_uplink(link
, &uplink
) < 0)
559 if (uplink
&& !uplink
->network
)
565 int request_process_dhcp_server(Request
*req
) {
568 assert(req
->type
== REQUEST_TYPE_DHCP_SERVER
);
570 if (!dhcp_server_is_ready_to_configure(req
->link
))
573 return dhcp4_server_configure(req
->link
);
576 int config_parse_dhcp_server_relay_agent_suboption(
578 const char *filename
,
581 unsigned section_line
,
588 char **suboption_value
= data
;
595 if (isempty(rvalue
)) {
596 *suboption_value
= mfree(*suboption_value
);
600 p
= startswith(rvalue
, "string:");
602 log_syntax(unit
, LOG_WARNING
, filename
, line
, 0,
603 "Failed to parse %s=%s'. Invalid format, ignoring.", lvalue
, rvalue
);
606 return free_and_strdup(suboption_value
, empty_to_null(p
));
609 int config_parse_dhcp_server_emit(
611 const char *filename
,
614 unsigned section_line
,
621 NetworkDHCPServerEmitAddress
*emit
= data
;
626 for (const char *p
= rvalue
;;) {
627 _cleanup_free_
char *w
= NULL
;
628 union in_addr_union a
;
631 r
= extract_first_word(&p
, &w
, NULL
, 0);
635 log_syntax(unit
, LOG_WARNING
, filename
, line
, r
,
636 "Failed to extract word, ignoring: %s", rvalue
);
642 if (streq(w
, "_server_address"))
643 a
= IN_ADDR_NULL
; /* null address will be converted to the server address. */
645 r
= in_addr_from_string(AF_INET
, w
, &a
);
647 log_syntax(unit
, LOG_WARNING
, filename
, line
, r
,
648 "Failed to parse %s= address '%s', ignoring: %m", lvalue
, w
);
652 if (in4_addr_is_null(&a
.in
)) {
653 log_syntax(unit
, LOG_WARNING
, filename
, line
, 0,
654 "Found a null address in %s=, ignoring.", lvalue
);
659 if (!GREEDY_REALLOC(emit
->addresses
, emit
->n_addresses
+ 1))
662 emit
->addresses
[emit
->n_addresses
++] = a
.in
;
666 int config_parse_dhcp_server_address(
668 const char *filename
,
671 unsigned section_line
,
678 Network
*network
= userdata
;
679 union in_addr_union a
;
680 unsigned char prefixlen
;
687 if (isempty(rvalue
)) {
688 network
->dhcp_server_address
= (struct in_addr
) {};
689 network
->dhcp_server_address_prefixlen
= 0;
693 r
= in_addr_prefix_from_string(rvalue
, AF_INET
, &a
, &prefixlen
);
695 log_syntax(unit
, LOG_WARNING
, filename
, line
, r
,
696 "Failed to parse %s=, ignoring assignment: %s", lvalue
, rvalue
);
699 if (in4_addr_is_null(&a
.in
) || in4_addr_is_localhost(&a
.in
)) {
700 log_syntax(unit
, LOG_WARNING
, filename
, line
, 0,
701 "DHCP server address cannot be the ANY address or a localhost address, "
702 "ignoring assignment: %s", rvalue
);
706 network
->dhcp_server_address
= a
.in
;
707 network
->dhcp_server_address_prefixlen
= prefixlen
;