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83cc7f7ea8089d9c3f3c2c0ca296c612b7ca02de
systemd/src/resolve/resolved-manager.c
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/* SPDX-License-Identifier: LGPL-2.1-or-later */
#include <fcntl.h>
#include <linux/ipv6.h>
#include <netinet/in.h>
#include <poll.h>
#include <unistd.h>
#include "sd-bus.h"
#include "sd-netlink.h"
#include "sd-network.h"
#include "af-list.h"
#include "alloc-util.h"
#include "daemon-util.h"
#include "dirent-util.h"
#include "dns-answer.h"
#include "dns-domain.h"
#include "dns-packet.h"
#include "dns-question.h"
#include "dns-rr.h"
#include "errno-util.h"
#include "event-util.h"
#include "fd-util.h"
#include "hostname-setup.h"
#include "hostname-util.h"
#include "io-util.h"
#include "iovec-util.h"
#include "json-util.h"
#include "memstream-util.h"
#include "missing-network.h"
#include "ordered-set.h"
#include "parse-util.h"
#include "random-util.h"
#include "resolved-bus.h"
#include "resolved-conf.h"
#include "resolved-dns-delegate.h"
#include "resolved-dns-query.h"
#include "resolved-dns-scope.h"
#include "resolved-dns-search-domain.h"
#include "resolved-dns-server.h"
#include "resolved-dns-stub.h"
#include "resolved-dns-transaction.h"
#include "resolved-dnssd.h"
#include "resolved-etc-hosts.h"
#include "resolved-link.h"
#include "resolved-llmnr.h"
#include "resolved-manager.h"
#include "resolved-mdns.h"
#include "resolved-resolv-conf.h"
#include "resolved-socket-graveyard.h"
#include "resolved-static-records.h"
#include "resolved-util.h"
#include "resolved-varlink.h"
#include "set.h"
#include "socket-util.h"
#include "string-util.h"
#include "time-util.h"
#include "varlink-util.h"
#define SEND_TIMEOUT_USEC (200 * USEC_PER_MSEC)
static int manager_process_link(sd_netlink *rtnl, sd_netlink_message *mm, void *userdata) {
Manager *m = ASSERT_PTR(userdata);
uint16_t type;
Link *l;
int ifindex, r;
assert(rtnl);
assert(mm);
r = sd_netlink_message_get_type(mm, &type);
if (r < 0)
goto fail;
r = sd_rtnl_message_link_get_ifindex(mm, &ifindex);
if (r < 0)
goto fail;
l = hashmap_get(m->links, INT_TO_PTR(ifindex));
switch (type) {
case RTM_NEWLINK:{
bool is_new = !l;
if (!l) {
r = link_new(m, &l, ifindex);
if (r < 0)
goto fail;
}
r = link_process_rtnl(l, mm);
if (r < 0)
goto fail;
r = link_update(l);
if (r < 0)
goto fail;
if (is_new)
log_debug("Found new link %i/%s", ifindex, l->ifname);
break;
}
case RTM_DELLINK:
if (l) {
log_debug("Removing link %i/%s", l->ifindex, l->ifname);
link_remove_user(l);
link_free(l);
/* Make sure DNS servers are dropped from written resolv.conf if their link goes away */
manager_write_resolv_conf(m);
}
break;
}
/* Now check all the links, and if mDNS/llmr are disabled everywhere, stop them globally too. */
manager_llmnr_maybe_stop(m);
manager_mdns_maybe_stop(m);
/* The accessible flag on link DNS servers will have been reset by
* link_update(). Just reset the global DNS servers. */
(void) manager_send_dns_configuration_changed(m, NULL, /* reset= */ true);
return 0;
fail:
log_warning_errno(r, "Failed to process RTNL link message: %m");
return 0;
}
static int manager_process_address(sd_netlink *rtnl, sd_netlink_message *mm, void *userdata) {
Manager *m = ASSERT_PTR(userdata);
union in_addr_union address, broadcast = {};
uint16_t type;
int r, ifindex, family;
LinkAddress *a;
Link *l;
assert(rtnl);
assert(mm);
r = sd_netlink_message_get_type(mm, &type);
if (r < 0)
goto fail;
r = sd_rtnl_message_addr_get_ifindex(mm, &ifindex);
if (r < 0)
goto fail;
l = hashmap_get(m->links, INT_TO_PTR(ifindex));
if (!l)
return 0;
r = sd_rtnl_message_addr_get_family(mm, &family);
if (r < 0)
goto fail;
switch (family) {
case AF_INET:
sd_netlink_message_read_in_addr(mm, IFA_BROADCAST, &broadcast.in);
r = sd_netlink_message_read_in_addr(mm, IFA_LOCAL, &address.in);
if (r < 0) {
r = sd_netlink_message_read_in_addr(mm, IFA_ADDRESS, &address.in);
if (r < 0)
goto fail;
}
break;
case AF_INET6:
r = sd_netlink_message_read_in6_addr(mm, IFA_LOCAL, &address.in6);
if (r < 0) {
r = sd_netlink_message_read_in6_addr(mm, IFA_ADDRESS, &address.in6);
if (r < 0)
goto fail;
}
break;
default:
return 0;
}
a = link_find_address(l, family, &address);
switch (type) {
case RTM_NEWADDR:
if (!a) {
r = link_address_new(l, &a, family, &address, &broadcast);
if (r < 0)
return r;
}
r = link_address_update_rtnl(a, mm);
if (r < 0)
return r;
break;
case RTM_DELADDR:
link_address_free(a);
break;
}
(void) manager_send_dns_configuration_changed(m, l, /* reset= */ true);
return 0;
fail:
log_warning_errno(r, "Failed to process RTNL address message: %m");
return 0;
}
static int manager_process_route(sd_netlink *rtnl, sd_netlink_message *mm, void *userdata) {
Manager *m = ASSERT_PTR(userdata);
Link *l = NULL;
uint16_t type;
uint32_t ifindex = 0;
int r;
assert(rtnl);
assert(mm);
r = sd_netlink_message_get_type(mm, &type);
if (r < 0) {
log_warning_errno(r, "Failed to get rtnl message type, ignoring: %m");
return 0;
}
if (!IN_SET(type, RTM_NEWROUTE, RTM_DELROUTE)) {
log_warning("Unexpected message type %u when processing route, ignoring.", type);
return 0;
}
r = sd_netlink_message_read_u32(mm, RTA_OIF, &ifindex);
if (r < 0)
log_full_errno(r == -ENODATA ? LOG_DEBUG : LOG_WARNING, r, "Failed to get route ifindex, ignoring: %m");
else
l = hashmap_get(m->links, INT_TO_PTR(ifindex));
(void) manager_send_dns_configuration_changed(m, l, /* reset= */ true);
return 0;
}
static int manager_rtnl_listen(Manager *m) {
_cleanup_(sd_netlink_message_unrefp) sd_netlink_message *req = NULL, *reply = NULL;
int r;
assert(m);
/* First, subscribe to interfaces coming and going */
r = sd_netlink_open(&m->rtnl);
if (r < 0)
return r;
r = sd_netlink_attach_event(m->rtnl, m->event, SD_EVENT_PRIORITY_IMPORTANT);
if (r < 0)
return r;
r = sd_netlink_add_match(m->rtnl, NULL, RTM_NEWLINK, manager_process_link, NULL, m, "resolve-NEWLINK");
if (r < 0)
return r;
r = sd_netlink_add_match(m->rtnl, NULL, RTM_DELLINK, manager_process_link, NULL, m, "resolve-DELLINK");
if (r < 0)
return r;
r = sd_netlink_add_match(m->rtnl, NULL, RTM_NEWADDR, manager_process_address, NULL, m, "resolve-NEWADDR");
if (r < 0)
return r;
r = sd_netlink_add_match(m->rtnl, NULL, RTM_DELADDR, manager_process_address, NULL, m, "resolve-DELADDR");
if (r < 0)
return r;
/* Then, enumerate all links */
r = sd_rtnl_message_new_link(m->rtnl, &req, RTM_GETLINK, 0);
if (r < 0)
return r;
r = sd_netlink_message_set_request_dump(req, true);
if (r < 0)
return r;
r = sd_netlink_call(m->rtnl, req, 0, &reply);
if (r < 0)
return r;
for (sd_netlink_message *i = reply; i; i = sd_netlink_message_next(i)) {
r = manager_process_link(m->rtnl, i, m);
if (r < 0)
return r;
}
req = sd_netlink_message_unref(req);
reply = sd_netlink_message_unref(reply);
/* Finally, enumerate all addresses, too */
r = sd_rtnl_message_new_addr(m->rtnl, &req, RTM_GETADDR, 0, AF_UNSPEC);
if (r < 0)
return r;
r = sd_netlink_message_set_request_dump(req, true);
if (r < 0)
return r;
r = sd_netlink_call(m->rtnl, req, 0, &reply);
if (r < 0)
return r;
for (sd_netlink_message *i = reply; i; i = sd_netlink_message_next(i)) {
r = manager_process_address(m->rtnl, i, m);
if (r < 0)
return r;
}
return r;
}
static int on_network_event(sd_event_source *source, int fd, uint32_t revents, void *userdata) {
Manager *m = ASSERT_PTR(userdata);
Link *l;
int r;
sd_network_monitor_flush(m->network_monitor);
HASHMAP_FOREACH(l, m->links) {
r = link_update(l);
if (r < 0)
log_warning_errno(r, "Failed to update monitor information for %i: %m", l->ifindex);
}
(void) manager_write_resolv_conf(m);
(void) manager_send_changed(m, "DNS");
(void) manager_send_dns_configuration_changed(m, NULL, /* reset= */ true);
/* Now check all the links, and if mDNS/llmr are disabled everywhere, stop them globally too. */
manager_llmnr_maybe_stop(m);
manager_mdns_maybe_stop(m);
return 0;
}
static int manager_network_monitor_listen(Manager *m) {
int r, fd, events;
assert(m);
r = sd_network_monitor_new(&m->network_monitor, NULL);
if (r < 0)
return r;
fd = sd_network_monitor_get_fd(m->network_monitor);
if (fd < 0)
return fd;
events = sd_network_monitor_get_events(m->network_monitor);
if (events < 0)
return events;
r = sd_event_add_io(m->event, &m->network_event_source, fd, events, &on_network_event, m);
if (r < 0)
return r;
r = sd_event_source_set_priority(m->network_event_source, SD_EVENT_PRIORITY_IMPORTANT-5);
if (r < 0)
return r;
(void) sd_event_source_set_description(m->network_event_source, "network-monitor");
return 0;
}
static int manager_clock_change_listen(Manager *m);
static int on_clock_change(sd_event_source *source, int fd, uint32_t revents, void *userdata) {
Manager *m = ASSERT_PTR(userdata);
/* The clock has changed, let's flush all caches. Why that? That's because DNSSEC validation takes
* the system clock into consideration, and if the clock changes the old validations might have been
* wrong. Let's redo all validation with the new, correct time.
*
* (Also, this is triggered after system suspend, which is also a good reason to drop caches, since
* we might be connected to a different network now without this being visible in a dropped link
* carrier or so.) */
log_info("Clock change detected. Flushing caches.");
manager_flush_caches(m, LOG_DEBUG /* downgrade the functions own log message, since we already logged here at LOG_INFO level */);
/* The clock change timerfd is unusable after it triggered once, create a new one. */
return manager_clock_change_listen(m);
}
static int manager_clock_change_listen(Manager *m) {
int r;
assert(m);
m->clock_change_event_source = sd_event_source_disable_unref(m->clock_change_event_source);
r = event_add_time_change(m->event, &m->clock_change_event_source, on_clock_change, m);
if (r < 0)
return log_error_errno(r, "Failed to create clock change event source: %m");
return 0;
}
static int determine_hostnames(char **full_hostname, char **llmnr_hostname, char **mdns_hostname) {
_cleanup_free_ char *h = NULL, *n = NULL;
int r;
assert(full_hostname);
assert(llmnr_hostname);
assert(mdns_hostname);
r = resolve_system_hostname(&h, &n);
if (r < 0)
return r;
r = dns_name_concat(n, "local", 0, mdns_hostname);
if (r < 0)
return log_error_errno(r, "Failed to determine mDNS hostname: %m");
*llmnr_hostname = TAKE_PTR(n);
*full_hostname = TAKE_PTR(h);
return 0;
}
static char* fallback_hostname(void) {
/* Determine the fall back hostname. For exposing this system to the outside world, we cannot have it
* to be "localhost" even if that's the default hostname. In this case, let's revert to "linux"
* instead. */
_cleanup_free_ char *n = get_default_hostname();
if (!n)
return NULL;
if (is_localhost(n))
return strdup("linux");
return TAKE_PTR(n);
}
static int make_fallback_hostnames(char **full_hostname, char **llmnr_hostname, char **mdns_hostname) {
_cleanup_free_ char *h = NULL, *n = NULL, *m = NULL;
char label[DNS_LABEL_MAX+1];
const char *p;
int r;
assert(full_hostname);
assert(llmnr_hostname);
assert(mdns_hostname);
p = h = fallback_hostname();
if (!h)
return log_oom();
r = dns_label_unescape(&p, label, sizeof label, 0);
if (r < 0)
return log_error_errno(r, "Failed to unescape fallback hostname: %m");
assert(r > 0); /* The fallback hostname must have at least one label */
r = dns_label_escape_new(label, r, &n);
if (r < 0)
return log_error_errno(r, "Failed to escape fallback hostname: %m");
r = dns_name_concat(n, "local", 0, &m);
if (r < 0)
return log_error_errno(r, "Failed to concatenate mDNS hostname: %m");
*llmnr_hostname = TAKE_PTR(n);
*mdns_hostname = TAKE_PTR(m);
*full_hostname = TAKE_PTR(h);
return 0;
}
static int on_hostname_change(sd_event_source *es, int fd, uint32_t revents, void *userdata) {
_cleanup_free_ char *full_hostname = NULL, *llmnr_hostname = NULL, *mdns_hostname = NULL;
Manager *m = ASSERT_PTR(userdata);
bool llmnr_hostname_changed;
int r;
r = determine_hostnames(&full_hostname, &llmnr_hostname, &mdns_hostname);
if (r < 0) {
log_warning_errno(r, "Failed to determine the local hostname and LLMNR/mDNS names, ignoring: %m");
return 0; /* ignore invalid hostnames */
}
llmnr_hostname_changed = !streq(llmnr_hostname, m->llmnr_hostname);
if (streq(full_hostname, m->full_hostname) &&
!llmnr_hostname_changed &&
streq(mdns_hostname, m->mdns_hostname))
return 0;
log_info("System hostname changed to '%s'.", full_hostname);
free_and_replace(m->full_hostname, full_hostname);
free_and_replace(m->llmnr_hostname, llmnr_hostname);
free_and_replace(m->mdns_hostname, mdns_hostname);
manager_refresh_rrs(m);
(void) manager_send_changed(m, "LLMNRHostname");
return 0;
}
static int manager_watch_hostname(Manager *m) {
int r;
assert(m);
m->hostname_fd = open("/proc/sys/kernel/hostname",
O_RDONLY|O_CLOEXEC|O_NONBLOCK|O_NOCTTY);
if (m->hostname_fd < 0) {
log_warning_errno(errno, "Failed to watch hostname: %m");
return 0;
}
r = sd_event_add_io(m->event, &m->hostname_event_source, m->hostname_fd, 0, on_hostname_change, m);
if (r < 0)
return log_error_errno(r, "Failed to add hostname event source: %m");
(void) sd_event_source_set_description(m->hostname_event_source, "hostname");
r = determine_hostnames(&m->full_hostname, &m->llmnr_hostname, &m->mdns_hostname);
if (r < 0) {
_cleanup_free_ char *d = NULL;
d = fallback_hostname();
if (!d)
return log_oom();
log_info("Defaulting to hostname '%s'.", d);
r = make_fallback_hostnames(&m->full_hostname, &m->llmnr_hostname, &m->mdns_hostname);
if (r < 0)
return r;
} else
log_info("Using system hostname '%s'.", m->full_hostname);
return 0;
}
static int manager_sigusr1(sd_event_source *s, const struct signalfd_siginfo *si, void *userdata) {
_cleanup_(memstream_done) MemStream ms = {};
Manager *m = ASSERT_PTR(userdata);
Link *l;
FILE *f;
assert(s);
assert(si);
f = memstream_init(&ms);
if (!f)
return log_oom();
LIST_FOREACH(scopes, scope, m->dns_scopes)
dns_scope_dump(scope, f);
LIST_FOREACH(servers, server, m->dns_servers)
dns_server_dump(server, f);
LIST_FOREACH(servers, server, m->fallback_dns_servers)
dns_server_dump(server, f);
HASHMAP_FOREACH(l, m->links)
LIST_FOREACH(servers, server, l->dns_servers)
dns_server_dump(server, f);
DnsDelegate *delegate;
HASHMAP_FOREACH(delegate, m->delegates)
LIST_FOREACH(servers, server, delegate->dns_servers)
dns_server_dump(server, f);
return memstream_dump(LOG_INFO, &ms);
}
static int manager_sigusr2(sd_event_source *s, const struct signalfd_siginfo *si, void *userdata) {
Manager *m = ASSERT_PTR(userdata);
assert(s);
assert(si);
manager_flush_caches(m, LOG_INFO);
return 0;
}
static int manager_sigrtmin1(sd_event_source *s, const struct signalfd_siginfo *si, void *userdata) {
Manager *m = ASSERT_PTR(userdata);
assert(s);
assert(si);
manager_reset_server_features(m);
return 0;
}
static int manager_memory_pressure(sd_event_source *s, void *userdata) {
Manager *m = ASSERT_PTR(userdata);
log_info("Under memory pressure, flushing caches.");
manager_flush_caches(m, LOG_INFO);
sd_event_trim_memory();
return 0;
}
static int manager_memory_pressure_listen(Manager *m) {
int r;
assert(m);
r = sd_event_add_memory_pressure(m->event, NULL, manager_memory_pressure, m);
if (r < 0)
log_full_errno(ERRNO_IS_NOT_SUPPORTED(r) || ERRNO_IS_PRIVILEGE(r) || (r == -EHOSTDOWN )? LOG_DEBUG : LOG_NOTICE, r,
"Failed to install memory pressure event source, ignoring: %m");
return 0;
}
static void manager_set_defaults(Manager *m) {
assert(m);
m->llmnr_support = DEFAULT_LLMNR_MODE;
m->mdns_support = DEFAULT_MDNS_MODE;
m->dnssec_mode = DEFAULT_DNSSEC_MODE;
m->dns_over_tls_mode = DEFAULT_DNS_OVER_TLS_MODE;
m->enable_cache = DNS_CACHE_MODE_YES;
m->dns_stub_listener_mode = DNS_STUB_LISTENER_YES;
m->read_etc_hosts = true;
m->read_static_records = true;
m->resolve_unicast_single_label = false;
m->cache_from_localhost = false;
for (DnsProtocol p = 0; p < _DNS_PROTOCOL_MAX; p++)
m->cache_max[p] = DEFAULT_CACHE_MAX;
m->stale_retention_usec = 0;
m->refuse_record_types = set_free(m->refuse_record_types);
m->resolv_conf_stat = (struct stat) {};
}
static int manager_dispatch_reload_signal(sd_event_source *s, const struct signalfd_siginfo *si, void *userdata) {
Manager *m = ASSERT_PTR(userdata);
Link *l;
int r;
(void) notify_reloading();
dns_server_unlink_on_reload(m->dns_servers);
dns_server_unlink_on_reload(m->fallback_dns_servers);
m->dns_extra_stub_listeners = ordered_set_free(m->dns_extra_stub_listeners);
manager_dns_stub_stop(m);
dnssd_registered_service_clear_on_reload(m->dnssd_registered_services);
m->unicast_scope = dns_scope_free(m->unicast_scope);
m->delegates = hashmap_free(m->delegates);
dns_trust_anchor_flush(&m->trust_anchor);
manager_etc_hosts_flush(m);
manager_static_records_flush(m);
m->etc_hosts_last = USEC_INFINITY;
m->static_records_last = USEC_INFINITY;
manager_set_defaults(m);
r = dns_trust_anchor_load(&m->trust_anchor);
if (r < 0)
return sd_event_exit(sd_event_source_get_event(s), r);
r = manager_parse_config_file(m);
if (r < 0)
log_warning_errno(r, "Failed to parse configuration file on reload, ignoring: %m");
else
log_info("Config file reloaded.");
(void) dnssd_load(m);
(void) manager_load_delegates(m);
/* The default scope configuration is influenced by the manager's configuration (modes, etc.), so
* recreate it on reload. */
r = dns_scope_new(m, &m->unicast_scope, DNS_SCOPE_GLOBAL, /* link= */ NULL, /* delegate= */ NULL, DNS_PROTOCOL_DNS, AF_UNSPEC);
if (r < 0)
return sd_event_exit(sd_event_source_get_event(s), r);
/* A link's unicast scope may also be influenced by the manager's configuration. I.e., DNSSEC= and DNSOverTLS=
* from the manager will be used if not explicitly configured on the link. Free the scopes here so that
* link_allocate_scopes() in on_network_event() re-creates them. */
HASHMAP_FOREACH(l, m->links)
l->unicast_scope = dns_scope_free(l->unicast_scope);
/* The configuration has changed, so reload the per-interface configuration too in order to take
* into account any changes (e.g.: enable/disable DNSSEC). */
r = on_network_event(/* source= */ NULL, -EBADF, /* revents= */ 0, m);
if (r < 0)
log_warning_errno(r, "Failed to update network information on reload, ignoring: %m");
/* We have new configuration, which means potentially new servers, so close all connections and drop
* all caches, so that we can start fresh. */
(void) dns_stream_disconnect_all(m);
manager_flush_caches(m, LOG_INFO);
manager_verify_all(m);
r = manager_dns_stub_start(m);
if (r < 0)
return sd_event_exit(sd_event_source_get_event(s), r);
(void) sd_notify(/* unset_environment= */ false, NOTIFY_READY_MESSAGE);
return 0;
}
int manager_new(Manager **ret) {
_cleanup_(manager_freep) Manager *m = NULL;
int r;
assert(ret);
m = new(Manager, 1);
if (!m)
return -ENOMEM;
*m = (Manager) {
.llmnr_ipv4_udp_fd = -EBADF,
.llmnr_ipv6_udp_fd = -EBADF,
.llmnr_ipv4_tcp_fd = -EBADF,
.llmnr_ipv6_tcp_fd = -EBADF,
.mdns_ipv4_fd = -EBADF,
.mdns_ipv6_fd = -EBADF,
.hostname_fd = -EBADF,
.read_resolv_conf = true,
.need_builtin_fallbacks = true,
.etc_hosts_last = USEC_INFINITY,
.static_records_last = USEC_INFINITY,
.sigrtmin18_info.memory_pressure_handler = manager_memory_pressure,
.sigrtmin18_info.memory_pressure_userdata = m,
};
manager_set_defaults(m);
r = dns_trust_anchor_load(&m->trust_anchor);
if (r < 0)
return r;
r = manager_parse_config_file(m);
if (r < 0)
log_warning_errno(r, "Failed to parse configuration file, ignoring: %m");
r = sd_event_default(&m->event);
if (r < 0)
return r;
r = sd_event_set_signal_exit(m->event, true);
if (r < 0)
return r;
(void) sd_event_set_watchdog(m->event, true);
r = manager_watch_hostname(m);
if (r < 0)
return r;
(void) dnssd_load(m);
(void) manager_load_delegates(m);
r = dns_scope_new(m, &m->unicast_scope, DNS_SCOPE_GLOBAL, /* link= */ NULL, /* delegate= */ NULL, DNS_PROTOCOL_DNS, AF_UNSPEC);
if (r < 0)
return r;
r = manager_network_monitor_listen(m);
if (r < 0)
return r;
r = manager_rtnl_listen(m);
if (r < 0)
return r;
r = manager_clock_change_listen(m);
if (r < 0)
return r;
r = manager_memory_pressure_listen(m);
if (r < 0)
return r;
r = manager_connect_bus(m);
if (r < 0)
return r;
r = sd_event_add_signal(m->event, /* ret= */ NULL, SIGHUP | SD_EVENT_SIGNAL_PROCMASK, manager_dispatch_reload_signal, m);
if (r < 0)
return log_debug_errno(r, "Failed to install SIGHUP handler: %m");
r = sd_event_add_signal(m->event, /* ret= */ NULL, SIGUSR1 | SD_EVENT_SIGNAL_PROCMASK, manager_sigusr1, m);
if (r < 0)
return log_debug_errno(r, "Failed to install SIGUSR1 handler: %m");
r = sd_event_add_signal(m->event, /* ret= */ NULL, SIGUSR2 | SD_EVENT_SIGNAL_PROCMASK, manager_sigusr2, m);
if (r < 0)
return log_debug_errno(r, "Failed to install SIGUSR2 handler: %m");
r = sd_event_add_signal(m->event, /* ret= */ NULL, (SIGRTMIN+1) | SD_EVENT_SIGNAL_PROCMASK, manager_sigrtmin1, m);
if (r < 0)
return log_debug_errno(r, "Failed to install SIGRTMIN+1 handler: %m");
r = sd_event_add_signal(m->event, /* ret= */ NULL, (SIGRTMIN+18) | SD_EVENT_SIGNAL_PROCMASK, sigrtmin18_handler, &m->sigrtmin18_info);
if (r < 0)
return log_debug_errno(r, "Failed to install SIGRTMIN+18 handler: %m");
manager_cleanup_saved_user(m);
*ret = TAKE_PTR(m);
return 0;
}
int manager_start(Manager *m) {
int r;
assert(m);
r = manager_dns_stub_start(m);
if (r < 0)
return r;
r = manager_varlink_init(m);
if (r < 0)
return r;
return 0;
}
Manager* manager_free(Manager *m) {
if (!m)
return NULL;
dns_server_unlink_all(m->dns_servers);
dns_server_unlink_all(m->fallback_dns_servers);
dns_search_domain_unlink_all(m->search_domains);
m->links = hashmap_free(m->links);
m->delegates = hashmap_free(m->delegates);
while (m->dns_queries)
dns_query_free(m->dns_queries);
m->stub_queries_by_packet = hashmap_free(m->stub_queries_by_packet);
m->unicast_scope = dns_scope_free(m->unicast_scope);
/* At this point only orphaned streams should remain. All others should have been freed already by their
* owners */
while (m->dns_streams)
dns_stream_unref(m->dns_streams);
#if ENABLE_DNS_OVER_TLS
dnstls_manager_free(m);
#endif
set_free(m->refuse_record_types);
hashmap_free(m->dns_transactions);
sd_event_source_unref(m->network_event_source);
sd_network_monitor_unref(m->network_monitor);
sd_netlink_slot_unref(m->netlink_new_route_slot);
sd_netlink_slot_unref(m->netlink_del_route_slot);
sd_netlink_unref(m->rtnl);
sd_event_source_unref(m->rtnl_event_source);
sd_event_source_unref(m->clock_change_event_source);
sd_json_variant_unref(m->dns_configuration_json);
manager_llmnr_stop(m);
manager_mdns_stop(m);
manager_dns_stub_stop(m);
manager_varlink_done(m);
set_free(m->varlink_query_results_subscription);
set_free(m->varlink_dns_configuration_subscription);
manager_socket_graveyard_clear(m);
ordered_set_free(m->dns_extra_stub_listeners);
hashmap_free(m->polkit_registry);
sd_bus_flush_close_unref(m->bus);
dns_resource_key_unref(m->llmnr_host_ipv4_key);
dns_resource_key_unref(m->llmnr_host_ipv6_key);
dns_resource_key_unref(m->mdns_host_ipv4_key);
dns_resource_key_unref(m->mdns_host_ipv6_key);
sd_event_source_unref(m->hostname_event_source);
safe_close(m->hostname_fd);
sd_event_unref(m->event);
free(m->full_hostname);
free(m->llmnr_hostname);
free(m->mdns_hostname);
hashmap_free(m->dnssd_registered_services);
dns_trust_anchor_flush(&m->trust_anchor);
manager_etc_hosts_flush(m);
manager_static_records_flush(m);
hashmap_free(m->dns_service_browsers);
hashmap_free(m->hooks);
return mfree(m);
}
int manager_recv(Manager *m, int fd, DnsProtocol protocol, DnsPacket **ret) {
_cleanup_(dns_packet_unrefp) DnsPacket *p = NULL;
CMSG_BUFFER_TYPE(CMSG_SPACE(MAXSIZE(struct in_pktinfo, struct in6_pktinfo))
+ CMSG_SPACE(int) /* ttl/hoplimit */
+ EXTRA_CMSG_SPACE /* kernel appears to require extra buffer space */) control;
union sockaddr_union sa;
struct iovec iov;
struct msghdr mh = {
.msg_name = &sa.sa,
.msg_namelen = sizeof(sa),
.msg_iov = &iov,
.msg_iovlen = 1,
.msg_control = &control,
.msg_controllen = sizeof(control),
};
struct cmsghdr *cmsg;
ssize_t ms, l;
int r;
assert(m);
assert(fd >= 0);
assert(ret);
ms = next_datagram_size_fd(fd);
/* The MSG_PEEK recv() in next_datagram_size_fd() validates the datagram's checksum, and drops it if
* it is bad. Hence we can end up here with nothing left to read even though the event source said
* otherwise, and must treat that like the recvmsg_safe() below does: as "no packet", not as a
* failure. Our callers propagate a failure to the event loop, which would then turn the listening
* socket's event source off for good. */
if (ERRNO_IS_NEG_TRANSIENT(ms))
return 0;
if (ms < 0)
return ms;
r = dns_packet_new(&p, protocol, ms, DNS_PACKET_SIZE_MAX);
if (r < 0)
return r;
iov = IOVEC_MAKE(DNS_PACKET_DATA(p), p->allocated);
l = recvmsg_safe(fd, &mh, 0);
if (ERRNO_IS_NEG_TRANSIENT(l))
return 0;
if (l <= 0)
return l;
p->size = (size_t) l;
p->family = sa.sa.sa_family;
p->ipproto = IPPROTO_UDP;
if (p->family == AF_INET) {
p->sender.in = sa.in.sin_addr;
p->sender_port = be16toh(sa.in.sin_port);
} else if (p->family == AF_INET6) {
p->sender.in6 = sa.in6.sin6_addr;
p->sender_port = be16toh(sa.in6.sin6_port);
p->ifindex = sa.in6.sin6_scope_id;
} else
return -EAFNOSUPPORT;
p->timestamp = now(CLOCK_BOOTTIME);
CMSG_FOREACH(cmsg, &mh) {
if (cmsg->cmsg_level == IPPROTO_IPV6) {
assert(p->family == AF_INET6);
switch (cmsg->cmsg_type) {
case IPV6_PKTINFO: {
struct in6_pktinfo *i = CMSG_TYPED_DATA(cmsg, struct in6_pktinfo);
if (p->ifindex <= 0)
p->ifindex = i->ipi6_ifindex;
p->destination.in6 = i->ipi6_addr;
break;
}
case IPV6_HOPLIMIT:
p->ttl = *CMSG_TYPED_DATA(cmsg, int);
break;
case IPV6_RECVFRAGSIZE:
p->fragsize = *CMSG_TYPED_DATA(cmsg, int);
break;
}
} else if (cmsg->cmsg_level == IPPROTO_IP) {
assert(p->family == AF_INET);
switch (cmsg->cmsg_type) {
case IP_PKTINFO: {
struct in_pktinfo *i = CMSG_TYPED_DATA(cmsg, struct in_pktinfo);
if (p->ifindex <= 0)
p->ifindex = i->ipi_ifindex;
p->destination.in = i->ipi_addr;
break;
}
case IP_TTL:
p->ttl = *CMSG_TYPED_DATA(cmsg, int);
break;
case IP_RECVFRAGSIZE:
p->fragsize = *CMSG_TYPED_DATA(cmsg, int);
break;
}
}
}
/* The Linux kernel sets the interface index to the loopback
* device if the packet came from the local host since it
* avoids the routing table in such a case. Let's unset the
* interface index in such a case. */
if (p->ifindex == LOOPBACK_IFINDEX)
p->ifindex = 0;
if (protocol != DNS_PROTOCOL_DNS) {
/* If we don't know the interface index still, we look for the
* first local interface with a matching address. Yuck! */
if (p->ifindex <= 0)
p->ifindex = manager_find_ifindex(m, p->family, &p->destination);
}
log_debug("Received %s UDP packet of size %zu, ifindex=%i, ttl=%u, fragsize=%zu, sender=%s, destination=%s",
dns_protocol_to_string(protocol), p->size, p->ifindex, p->ttl, p->fragsize,
IN_ADDR_TO_STRING(p->family, &p->sender),
IN_ADDR_TO_STRING(p->family, &p->destination));
*ret = TAKE_PTR(p);
return 1;
}
int sendmsg_loop(int fd, struct msghdr *mh, int flags) {
usec_t end;
int r;
assert(fd >= 0);
assert(mh);
end = usec_add(now(CLOCK_MONOTONIC), SEND_TIMEOUT_USEC);
for (;;) {
if (sendmsg(fd, mh, flags) >= 0)
return 0;
if (errno == EINTR)
continue;
if (errno != EAGAIN)
return -errno;
r = fd_wait_for_event(fd, POLLOUT, LESS_BY(end, now(CLOCK_MONOTONIC)));
if (ERRNO_IS_NEG_TRANSIENT(r))
continue;
if (r < 0)
return r;
if (r == 0)
return -ETIMEDOUT;
}
}
static int write_loop(int fd, void *message, size_t length) {
usec_t end;
int r;
assert(fd >= 0);
assert(message);
end = usec_add(now(CLOCK_MONOTONIC), SEND_TIMEOUT_USEC);
for (;;) {
if (write(fd, message, length) >= 0)
return 0;
if (errno == EINTR)
continue;
if (errno != EAGAIN)
return -errno;
r = fd_wait_for_event(fd, POLLOUT, LESS_BY(end, now(CLOCK_MONOTONIC)));
if (ERRNO_IS_NEG_TRANSIENT(r))
continue;
if (r < 0)
return r;
if (r == 0)
return -ETIMEDOUT;
}
}
int manager_write(Manager *m, int fd, DnsPacket *p) {
int r;
log_debug("Sending %s%s packet with id %" PRIu16 " of size %zu.",
DNS_PACKET_TC(p) ? "truncated (!) " : "",
DNS_PACKET_QR(p) ? "response" : "query",
DNS_PACKET_ID(p),
p->size);
r = write_loop(fd, DNS_PACKET_DATA(p), p->size);
if (r < 0)
return r;
return 0;
}
static int manager_ipv4_send(
Manager *m,
int fd,
int ifindex,
const struct in_addr *destination,
uint16_t port,
const struct in_addr *source,
DnsPacket *p) {
CMSG_BUFFER_TYPE(CMSG_SPACE(sizeof(struct in_pktinfo))) control = {};
union sockaddr_union sa;
struct iovec iov;
struct msghdr mh = {
.msg_iov = &iov,
.msg_iovlen = 1,
.msg_name = &sa.sa,
.msg_namelen = sizeof(sa.in),
};
assert(m);
assert(fd >= 0);
assert(destination);
assert(port > 0);
assert(p);
iov = IOVEC_MAKE(DNS_PACKET_DATA(p), p->size);
sa = (union sockaddr_union) {
.in.sin_family = AF_INET,
.in.sin_addr = *destination,
.in.sin_port = htobe16(port),
};
if (ifindex > 0) {
struct cmsghdr *cmsg;
struct in_pktinfo *pi;
mh.msg_control = &control;
mh.msg_controllen = sizeof(control);
cmsg = CMSG_FIRSTHDR(&mh);
cmsg->cmsg_len = CMSG_LEN(sizeof(struct in_pktinfo));
cmsg->cmsg_level = IPPROTO_IP;
cmsg->cmsg_type = IP_PKTINFO;
pi = CMSG_TYPED_DATA(cmsg, struct in_pktinfo);
pi->ipi_ifindex = ifindex;
if (source)
pi->ipi_spec_dst = *source;
}
return sendmsg_loop(fd, &mh, 0);
}
static int manager_ipv6_send(
Manager *m,
int fd,
int ifindex,
const struct in6_addr *destination,
uint16_t port,
const struct in6_addr *source,
DnsPacket *p) {
CMSG_BUFFER_TYPE(CMSG_SPACE(sizeof(struct in6_pktinfo))) control = {};
union sockaddr_union sa;
struct iovec iov;
struct msghdr mh = {
.msg_iov = &iov,
.msg_iovlen = 1,
.msg_name = &sa.sa,
.msg_namelen = sizeof(sa.in6),
};
assert(m);
assert(fd >= 0);
assert(destination);
assert(port > 0);
assert(p);
iov = IOVEC_MAKE(DNS_PACKET_DATA(p), p->size);
sa = (union sockaddr_union) {
.in6.sin6_family = AF_INET6,
.in6.sin6_addr = *destination,
.in6.sin6_port = htobe16(port),
.in6.sin6_scope_id = ifindex,
};
if (ifindex > 0) {
struct cmsghdr *cmsg;
struct in6_pktinfo *pi;
mh.msg_control = &control;
mh.msg_controllen = sizeof(control);
cmsg = CMSG_FIRSTHDR(&mh);
cmsg->cmsg_len = CMSG_LEN(sizeof(struct in6_pktinfo));
cmsg->cmsg_level = IPPROTO_IPV6;
cmsg->cmsg_type = IPV6_PKTINFO;
pi = CMSG_TYPED_DATA(cmsg, struct in6_pktinfo);
pi->ipi6_ifindex = ifindex;
if (source)
pi->ipi6_addr = *source;
}
return sendmsg_loop(fd, &mh, 0);
}
static int dns_question_to_json(DnsQuestion *q, sd_json_variant **ret) {
_cleanup_(sd_json_variant_unrefp) sd_json_variant *l = NULL;
DnsResourceKey *key;
int r;
assert(ret);
DNS_QUESTION_FOREACH(key, q) {
_cleanup_(sd_json_variant_unrefp) sd_json_variant *v = NULL;
r = dns_resource_key_to_json(key, &v);
if (r < 0)
return r;
r = sd_json_variant_append_array(&l, v);
if (r < 0)
return r;
}
*ret = TAKE_PTR(l);
return 0;
}
int manager_monitor_send(Manager *m, DnsQuery *q) {
_cleanup_(sd_json_variant_unrefp) sd_json_variant *jquestion = NULL, *jcollected_questions = NULL, *janswer = NULL;
_cleanup_(dns_question_unrefp) DnsQuestion *merged = NULL;
DnsAnswerItem *rri;
int r;
assert(m);
if (set_isempty(m->varlink_query_results_subscription))
return 0;
/* Merge all questions into one */
r = dns_question_merge(q->question_idna, q->question_utf8, &merged);
if (r < 0)
return log_error_errno(r, "Failed to merge UTF8/IDNA questions: %m");
if (q->question_bypass) {
_cleanup_(dns_question_unrefp) DnsQuestion *merged2 = NULL;
r = dns_question_merge(merged, q->question_bypass->question, &merged2);
if (r < 0)
return log_error_errno(r, "Failed to merge UTF8/IDNA questions and DNS packet question: %m");
dns_question_unref(merged);
merged = TAKE_PTR(merged2);
}
/* Convert the current primary question to JSON */
r = dns_question_to_json(merged, &jquestion);
if (r < 0)
return log_error_errno(r, "Failed to convert question to JSON: %m");
/* Generate a JSON array of the questions preceding the current one in the CNAME chain */
r = dns_question_to_json(q->collected_questions, &jcollected_questions);
if (r < 0)
return log_error_errno(r, "Failed to convert question to JSON: %m");
DNS_ANSWER_FOREACH_ITEM(rri, q->answer) {
_cleanup_(sd_json_variant_unrefp) sd_json_variant *v = NULL;
r = dns_resource_record_to_json(rri->rr, &v);
if (r < 0)
return log_error_errno(r, "Failed to convert answer resource record to JSON: %m");
r = dns_resource_record_to_wire_format(rri->rr, /* canonical= */ false); /* don't use DNSSEC canonical format, since it removes casing, but we want that for DNS_SD compat */
if (r < 0)
return log_error_errno(r, "Failed to generate RR wire format: %m");
r = sd_json_variant_append_arraybo(
&janswer,
SD_JSON_BUILD_PAIR_CONDITION(!!v, "rr", SD_JSON_BUILD_VARIANT(v)),
SD_JSON_BUILD_PAIR_BASE64("raw", rri->rr->wire_format, rri->rr->wire_format_size),
SD_JSON_BUILD_PAIR_CONDITION(rri->ifindex > 0, "ifindex", SD_JSON_BUILD_INTEGER(rri->ifindex)));
if (r < 0)
return log_debug_errno(r, "Failed to append notification entry to array: %m");
}
r = varlink_many_notifybo(
m->varlink_query_results_subscription,
SD_JSON_BUILD_PAIR_STRING("state", dns_transaction_state_to_string(q->state)),
SD_JSON_BUILD_PAIR_CONDITION(q->state == DNS_TRANSACTION_DNSSEC_FAILED,
"result", SD_JSON_BUILD_STRING(dnssec_result_to_string(q->answer_dnssec_result))),
SD_JSON_BUILD_PAIR_CONDITION(q->state == DNS_TRANSACTION_RCODE_FAILURE,
"rcode", SD_JSON_BUILD_INTEGER(q->answer_rcode)),
SD_JSON_BUILD_PAIR_CONDITION(q->state == DNS_TRANSACTION_ERRNO,
"errno", SD_JSON_BUILD_INTEGER(q->answer_errno)),
SD_JSON_BUILD_PAIR_CONDITION(IN_SET(q->state,
DNS_TRANSACTION_DNSSEC_FAILED,
DNS_TRANSACTION_RCODE_FAILURE) &&
q->answer_ede_rcode >= 0,
"extendedDNSErrorCode", SD_JSON_BUILD_INTEGER(q->answer_ede_rcode)),
SD_JSON_BUILD_PAIR_CONDITION(IN_SET(q->state,
DNS_TRANSACTION_DNSSEC_FAILED,
DNS_TRANSACTION_RCODE_FAILURE) &&
q->answer_ede_rcode >= 0 && !isempty(q->answer_ede_msg),
"extendedDNSErrorMessage", SD_JSON_BUILD_STRING(q->answer_ede_msg)),
SD_JSON_BUILD_PAIR_VARIANT("question", jquestion),
SD_JSON_BUILD_PAIR_CONDITION(!!jcollected_questions,
"collectedQuestions", SD_JSON_BUILD_VARIANT(jcollected_questions)),
SD_JSON_BUILD_PAIR_CONDITION(!!janswer,
"answer", SD_JSON_BUILD_VARIANT(janswer)));
if (r < 0)
log_debug_errno(r, "Failed to send monitor event, ignoring: %m");
return 0;
}
int manager_send(
Manager *m,
int fd,
int ifindex,
int family,
const union in_addr_union *destination,
uint16_t port,
const union in_addr_union *source,
DnsPacket *p) {
assert(m);
assert(fd >= 0);
assert(destination);
assert(port > 0);
assert(p);
/* For mDNS, it is natural that the packet have truncated flag when we have many known answers. */
bool truncated = DNS_PACKET_TC(p) && (p->protocol != DNS_PROTOCOL_MDNS || !p->more);
log_debug("Sending %s%s packet with id %" PRIu16 " on interface %i/%s of size %zu.",
truncated ? "truncated (!) " : "",
DNS_PACKET_QR(p) ? "response" : "query",
DNS_PACKET_ID(p),
ifindex, af_to_name(family),
p->size);
if (family == AF_INET)
return manager_ipv4_send(m, fd, ifindex, &destination->in, port, source ? &source->in : NULL, p);
if (family == AF_INET6)
return manager_ipv6_send(m, fd, ifindex, &destination->in6, port, source ? &source->in6 : NULL, p);
return -EAFNOSUPPORT;
}
uint32_t manager_find_mtu(Manager *m) {
uint32_t mtu = 0;
Link *l;
/* If we don't know on which link a DNS packet would be delivered, let's find the largest MTU that
* works on all interfaces we know of that have an IP address associated */
HASHMAP_FOREACH(l, m->links) {
/* Let's filter out links without IP addresses (e.g. AF_CAN links and suchlike) */
if (!l->addresses)
continue;
/* Safety check: MTU shorter than what we need for the absolutely shortest DNS request? Then
* let's ignore this link. */
if (l->mtu < MIN(UDP4_PACKET_HEADER_SIZE + DNS_PACKET_HEADER_SIZE,
UDP6_PACKET_HEADER_SIZE + DNS_PACKET_HEADER_SIZE))
continue;
if (mtu <= 0 || l->mtu < mtu)
mtu = l->mtu;
}
if (mtu == 0) /* found nothing? then let's assume the typical Ethernet MTU for lack of anything more precise */
return 1500;
return mtu;
}
int manager_find_ifindex(Manager *m, int family, const union in_addr_union *in_addr) {
LinkAddress *a;
assert(m);
if (!IN_SET(family, AF_INET, AF_INET6))
return 0;
if (!in_addr)
return 0;
a = manager_find_link_address(m, family, in_addr);
if (a)
return a->link->ifindex;
return 0;
}
void manager_refresh_rrs(Manager *m) {
Link *l;
DnssdRegisteredService *s;
assert(m);
m->llmnr_host_ipv4_key = dns_resource_key_unref(m->llmnr_host_ipv4_key);
m->llmnr_host_ipv6_key = dns_resource_key_unref(m->llmnr_host_ipv6_key);
m->mdns_host_ipv4_key = dns_resource_key_unref(m->mdns_host_ipv4_key);
m->mdns_host_ipv6_key = dns_resource_key_unref(m->mdns_host_ipv6_key);
HASHMAP_FOREACH(l, m->links)
link_add_rrs(l, true);
if (m->mdns_support == RESOLVE_SUPPORT_YES)
HASHMAP_FOREACH(s, m->dnssd_registered_services)
if (dnssd_update_rrs(s) < 0)
log_warning("Failed to refresh DNS-SD service '%s'", s->id);
HASHMAP_FOREACH(l, m->links)
link_add_rrs(l, false);
}
static int manager_next_random_name(const char *old, char **ret_new) {
const char *p;
uint64_t u, a;
char *n;
assert(ret_new);
p = strchr(old, 0);
assert(p);
while (p > old) {
if (!ascii_isdigit(p[-1]))
break;
p--;
}
if (*p == 0 || safe_atou64(p, &u) < 0 || u <= 0)
u = 1;
/* Add a random number to the old value. This way we can avoid
* that two hosts pick the same hostname, win on IPv4 and lose
* on IPv6 (or vice versa), and pick the same hostname
* replacement hostname, ad infinitum. We still want the
* numbers to go up monotonically, hence we just add a random
* value 1..10 */
random_bytes(&a, sizeof(a));
u += 1 + a % 10;
if (asprintf(&n, "%.*s%" PRIu64, (int) (p - old), old, u) < 0)
return -ENOMEM;
*ret_new = n;
return 0;
}
int manager_next_hostname(Manager *m) {
_cleanup_free_ char *h = NULL, *k = NULL;
int r;
assert(m);
r = manager_next_random_name(m->llmnr_hostname, &h);
if (r < 0)
return r;
r = dns_name_concat(h, "local", 0, &k);
if (r < 0)
return r;
log_info("Hostname conflict, changing published hostname from '%s' to '%s'.", m->llmnr_hostname, h);
free_and_replace(m->llmnr_hostname, h);
free_and_replace(m->mdns_hostname, k);
manager_refresh_rrs(m);
(void) manager_send_changed(m, "LLMNRHostname");
return 0;
}
LinkAddress* manager_find_link_address(Manager *m, int family, const union in_addr_union *in_addr) {
Link *l;
assert(m);
if (!IN_SET(family, AF_INET, AF_INET6))
return NULL;
if (!in_addr)
return NULL;
HASHMAP_FOREACH(l, m->links) {
LinkAddress *a;
a = link_find_address(l, family, in_addr);
if (a)
return a;
}
return NULL;
}
bool manager_packet_from_local_address(Manager *m, DnsPacket *p) {
assert(m);
assert(p);
/* Let's see if this packet comes from an IP address we have on any local interface */
return !!manager_find_link_address(m, p->family, &p->sender);
}
bool manager_packet_from_our_transaction(Manager *m, DnsPacket *p) {
DnsTransaction *t;
assert(m);
assert(p);
/* Let's see if we have a transaction with a query message with the exact same binary contents as the
* one we just got. If so, it's almost definitely a packet loop of some kind. */
t = hashmap_get(m->dns_transactions, UINT_TO_PTR(DNS_PACKET_ID(p)));
if (!t)
return false;
return t->sent && dns_packet_equal(t->sent, p);
}
DnsScope* manager_find_scope_from_protocol(Manager *m, int ifindex, DnsProtocol protocol, int family) {
Link *l;
assert(m);
l = hashmap_get(m->links, INT_TO_PTR(ifindex));
if (!l)
return NULL;
switch (protocol) {
case DNS_PROTOCOL_LLMNR:
if (family == AF_INET)
return l->llmnr_ipv4_scope;
else if (family == AF_INET6)
return l->llmnr_ipv6_scope;
break;
case DNS_PROTOCOL_MDNS:
if (family == AF_INET)
return l->mdns_ipv4_scope;
else if (family == AF_INET6)
return l->mdns_ipv6_scope;
break;
default:
;
}
return NULL;
}
void manager_verify_all(Manager *m) {
assert(m);
LIST_FOREACH(scopes, s, m->dns_scopes)
dns_zone_verify_all(&s->zone);
}
int manager_is_own_hostname(Manager *m, const char *name) {
int r;
assert(m);
assert(name);
if (m->llmnr_hostname) {
r = dns_name_equal(name, m->llmnr_hostname);
if (r != 0)
return r;
}
if (m->mdns_hostname) {
r = dns_name_equal(name, m->mdns_hostname);
if (r != 0)
return r;
}
if (m->full_hostname)
return dns_name_equal(name, m->full_hostname);
return 0;
}
int manager_compile_dns_servers(Manager *m, OrderedSet **servers) {
Link *l;
int r;
assert(m);
assert(servers);
r = ordered_set_ensure_allocated(servers, &dns_server_hash_ops);
if (r < 0)
return r;
/* First add the system-wide servers and domains */
LIST_FOREACH(servers, s, m->dns_servers) {
r = ordered_set_put(*servers, s);
if (r == -EEXIST)
continue;
if (r < 0)
return r;
}
/* Then, add the per-link servers */
HASHMAP_FOREACH(l, m->links)
LIST_FOREACH(servers, s, l->dns_servers) {
r = ordered_set_put(*servers, s);
if (r == -EEXIST)
continue;
if (r < 0)
return r;
}
/* Third, add the delegate servers and domains */
DnsDelegate *d;
HASHMAP_FOREACH(d, m->delegates)
LIST_FOREACH(servers, s, d->dns_servers) {
r = ordered_set_put(*servers, s);
if (r == -EEXIST)
continue;
if (r < 0)
return r;
}
/* If we found nothing, add the fallback servers */
if (ordered_set_isempty(*servers)) {
LIST_FOREACH(servers, s, m->fallback_dns_servers) {
r = ordered_set_put(*servers, s);
if (r == -EEXIST)
continue;
if (r < 0)
return r;
}
}
return 0;
}
/* filter_route is a tri-state:
* < 0: no filtering
* = 0 or false: return only domains which should be used for searching
* > 0 or true: return only domains which are for routing only
*/
int manager_compile_search_domains(Manager *m, OrderedSet **domains, int filter_route) {
int r;
assert(m);
assert(domains);
r = ordered_set_ensure_allocated(domains, &dns_name_hash_ops);
if (r < 0)
return r;
LIST_FOREACH(domains, d, m->search_domains) {
if (filter_route >= 0 &&
d->route_only != !!filter_route)
continue;
r = ordered_set_put(*domains, d->name);
if (r == -EEXIST)
continue;
if (r < 0)
return r;
}
DnsDelegate *delegate;
HASHMAP_FOREACH(delegate, m->delegates)
LIST_FOREACH(domains, d, delegate->search_domains) {
if (filter_route >= 0 &&
d->route_only != !!filter_route)
continue;
r = ordered_set_put(*domains, d->name);
if (r == -EEXIST)
continue;
if (r < 0)
return r;
}
Link *l;
HASHMAP_FOREACH(l, m->links)
LIST_FOREACH(domains, d, l->search_domains) {
if (filter_route >= 0 &&
d->route_only != !!filter_route)
continue;
r = ordered_set_put(*domains, d->name);
if (r == -EEXIST)
continue;
if (r < 0)
return r;
}
return 0;
}
DnssecMode manager_get_dnssec_mode(Manager *m) {
assert(m);
if (m->dnssec_mode != _DNSSEC_MODE_INVALID)
return m->dnssec_mode;
return DNSSEC_NO;
}
bool manager_dnssec_supported(Manager *m) {
DnsServer *server;
Link *l;
assert(m);
if (manager_get_dnssec_mode(m) == DNSSEC_NO)
return false;
server = manager_get_dns_server(m);
if (server && !dns_server_dnssec_supported(server))
return false;
HASHMAP_FOREACH(l, m->links)
if (!link_dnssec_supported(l))
return false;
return true;
}
DnsOverTlsMode manager_get_dns_over_tls_mode(Manager *m) {
assert(m);
if (m->dns_over_tls_mode != _DNS_OVER_TLS_MODE_INVALID)
return m->dns_over_tls_mode;
return DNS_OVER_TLS_NO;
}
void manager_dnssec_verdict(Manager *m, DnssecVerdict verdict, const DnsResourceKey *key) {
assert(verdict >= 0);
assert(verdict < _DNSSEC_VERDICT_MAX);
if (DEBUG_LOGGING) {
char s[DNS_RESOURCE_KEY_STRING_MAX];
log_debug("Found verdict for lookup %s: %s",
dns_resource_key_to_string(key, s, sizeof s),
dnssec_verdict_to_string(verdict));
}
m->n_dnssec_verdict[verdict]++;
}
bool manager_routable(Manager *m) {
Link *l;
assert(m);
/* Returns true if the host has at least one interface with a routable address (regardless if IPv4 or IPv6) */
HASHMAP_FOREACH(l, m->links)
if (link_relevant(l, AF_UNSPEC, false))
return true;
return false;
}
void manager_flush_caches(Manager *m, int log_level) {
assert(m);
LIST_FOREACH(scopes, scope, m->dns_scopes)
dns_cache_flush(&scope->cache);
dns_browse_services_purge(m, AF_UNSPEC); /* Clear records of DNS service browse subscriber, since caches are flushed */
dns_browse_services_restart(m);
log_full(log_level, "Flushed all caches.");
}
void manager_reset_server_features(Manager *m) {
dns_server_reset_features_all(m->dns_servers);
dns_server_reset_features_all(m->fallback_dns_servers);
Link *l;
HASHMAP_FOREACH(l, m->links)
dns_server_reset_features_all(l->dns_servers);
DnsDelegate *d;
HASHMAP_FOREACH(d, m->delegates)
dns_server_reset_features_all(d->dns_servers);
log_info("Resetting learnt feature levels on all servers.");
}
void manager_cleanup_saved_user(Manager *m) {
_cleanup_closedir_ DIR *d = NULL;
assert(m);
/* Clean up all saved per-link files in /run/systemd/resolve/netif/ that don't have a matching interface
* anymore. These files are created to persist settings pushed in by the user via the bus, so that resolved can
* be restarted without losing this data. */
d = opendir("/run/systemd/resolve/netif/");
if (!d) {
if (errno == ENOENT)
return;
log_warning_errno(errno, "Failed to open interface directory: %m");
return;
}
FOREACH_DIRENT_ALL(de, d, log_error_errno(errno, "Failed to read interface directory: %m")) {
int ifindex;
Link *l;
if (!IN_SET(de->d_type, DT_UNKNOWN, DT_REG))
continue;
if (dot_or_dot_dot(de->d_name))
continue;
ifindex = parse_ifindex(de->d_name);
if (ifindex < 0) /* Probably some temporary file from a previous run. Delete it */
goto rm;
l = hashmap_get(m->links, INT_TO_PTR(ifindex));
if (!l) /* link vanished */
goto rm;
if (l->is_managed) /* now managed by networkd, hence the bus settings are useless */
goto rm;
continue;
rm:
if (unlinkat(dirfd(d), de->d_name, 0) < 0)
log_warning_errno(errno, "Failed to remove left-over interface configuration file '%s', ignoring: %m", de->d_name);
}
}
bool manager_next_dnssd_names(Manager *m) {
DnssdRegisteredService *s;
bool tried = false;
int r;
assert(m);
HASHMAP_FOREACH(s, m->dnssd_registered_services) {
_cleanup_free_ char * new_name = NULL;
if (!s->withdrawn)
continue;
r = manager_next_random_name(s->name_template, &new_name);
if (r < 0) {
log_warning_errno(r, "Failed to get new name for service '%s': %m", s->id);
continue;
}
free_and_replace(s->name_template, new_name);
s->withdrawn = false;
tried = true;
}
if (tried)
manager_refresh_rrs(m);
return tried;
}
bool manager_server_is_stub(Manager *m, DnsServer *s) {
DnsStubListenerExtra *l;
assert(m);
assert(s);
/* Safety check: we generally already skip the main stub when parsing configuration. But let's be
* extra careful, and check here again */
if (s->family == AF_INET &&
s->address.in.s_addr == htobe32(INADDR_DNS_STUB) &&
dns_server_port(s) == 53)
return true;
/* Main reason to call this is to check server data against the extra listeners, and filter things
* out. */
ORDERED_SET_FOREACH(l, m->dns_extra_stub_listeners)
if (s->family == l->family &&
in_addr_equal(s->family, &s->address, &l->address) &&
dns_server_port(s) == dns_stub_listener_extra_port(l))
return true;
return false;
}
int socket_disable_pmtud(int fd, int af) {
int r;
assert(fd >= 0);
if (af == AF_UNSPEC) {
af = socket_get_family(fd);
if (af < 0)
return af;
}
switch (af) {
case AF_INET: {
/* Turn off path MTU discovery, let's rather fragment on the way than to open us up against
* PMTU forgery vulnerabilities.
*
* There appears to be no documentation about IP_PMTUDISC_OMIT, but it has the effect that
* the "Don't Fragment" bit in the IPv4 header is turned off, thus enforcing fragmentation if
* our datagram size exceeds the MTU of a router in the path, and turning off path MTU
* discovery.
*
* This helps mitigating the PMTUD vulnerability described here:
*
* https://blog.apnic.net/2019/07/12/its-time-to-consider-avoiding-ip-fragmentation-in-the-dns/
*
* Similar logic is in place in most DNS servers.
*
* There are multiple conflicting goals: we want to allow the largest datagrams possible (for
* efficiency reasons), but not have fragmentation (for security reasons), nor use PMTUD (for
* security reasons, too). Our strategy to deal with this is: use large packets, turn off
* PMTUD, but watch fragmentation taking place, and then size our packets to the max of the
* fragments seen — and if we need larger packets always go to TCP.
*/
r = setsockopt_int(fd, IPPROTO_IP, IP_MTU_DISCOVER, IP_PMTUDISC_OMIT);
if (r < 0)
return r;
return 0;
}
case AF_INET6: {
/* On IPv6 fragmentation only is done by the sender — never by routers on the path. PMTUD is
* mandatory. If we want to turn off PMTUD, the only way is by sending with minimal MTU only,
* so that we apply maximum fragmentation locally already, and thus PMTUD doesn't happen
* because there's nothing that could be fragmented further anymore. */
r = setsockopt_int(fd, IPPROTO_IPV6, IPV6_MTU, IPV6_MIN_MTU);
if (r < 0)
return r;
return 0;
}
default:
return -EAFNOSUPPORT;
}
}
int dns_manager_dump_statistics_json(Manager *m, sd_json_variant **ret) {
uint64_t size = 0, hit = 0, miss = 0;
assert(m);
assert(ret);
LIST_FOREACH(scopes, s, m->dns_scopes) {
size += dns_cache_size(&s->cache);
hit += s->cache.n_hit;
miss += s->cache.n_miss;
}
return sd_json_buildo(ret,
SD_JSON_BUILD_PAIR("transactions", SD_JSON_BUILD_OBJECT(
SD_JSON_BUILD_PAIR_UNSIGNED("currentTransactions", hashmap_size(m->dns_transactions)),
SD_JSON_BUILD_PAIR_UNSIGNED("totalTransactions", m->n_transactions_total),
SD_JSON_BUILD_PAIR_UNSIGNED("totalTimeouts", m->n_timeouts_total),
SD_JSON_BUILD_PAIR_UNSIGNED("totalTimeoutsServedStale", m->n_timeouts_served_stale_total),
SD_JSON_BUILD_PAIR_UNSIGNED("totalFailedResponses", m->n_failure_responses_total),
SD_JSON_BUILD_PAIR_UNSIGNED("totalFailedResponsesServedStale", m->n_failure_responses_served_stale_total)
)),
SD_JSON_BUILD_PAIR("cache", SD_JSON_BUILD_OBJECT(
SD_JSON_BUILD_PAIR_UNSIGNED("size", size),
SD_JSON_BUILD_PAIR_UNSIGNED("hits", hit),
SD_JSON_BUILD_PAIR_UNSIGNED("misses", miss)
)),
SD_JSON_BUILD_PAIR("dnssec", SD_JSON_BUILD_OBJECT(
SD_JSON_BUILD_PAIR_UNSIGNED("secure", m->n_dnssec_verdict[DNSSEC_SECURE]),
SD_JSON_BUILD_PAIR_UNSIGNED("insecure", m->n_dnssec_verdict[DNSSEC_INSECURE]),
SD_JSON_BUILD_PAIR_UNSIGNED("bogus", m->n_dnssec_verdict[DNSSEC_BOGUS]),
SD_JSON_BUILD_PAIR_UNSIGNED("indeterminate", m->n_dnssec_verdict[DNSSEC_INDETERMINATE])
)));
}
void dns_manager_reset_statistics(Manager *m) {
assert(m);
LIST_FOREACH(scopes, s, m->dns_scopes)
s->cache.n_hit = s->cache.n_miss = 0;
m->n_transactions_total = 0;
m->n_timeouts_total = 0;
m->n_timeouts_served_stale_total = 0;
m->n_failure_responses_total = 0;
m->n_failure_responses_served_stale_total = 0;
zero(m->n_dnssec_verdict);
}
static int dns_configuration_json_append(
const char *ifname,
int ifindex,
const char *delegate,
int default_route,
DnsServer *current_dns_server,
DnsServer *dns_servers,
DnsServer *fallback_dns_servers,
DnsSearchDomain *search_domains,
Set *negative_trust_anchors,
Set *dns_scopes,
DnssecMode dnssec_mode,
bool dnssec_supported,
DnsOverTlsMode dns_over_tls_mode,
ResolveSupport llmnr_support,
ResolveSupport mdns_support,
ResolvConfMode resolv_conf_mode,
sd_json_variant **configuration) {
_cleanup_(sd_json_variant_unrefp) sd_json_variant *dns_servers_json = NULL,
*fallback_dns_servers_json = NULL,
*search_domains_json = NULL,
*current_dns_server_json = NULL,
*scopes_json = NULL;
DnsScope *scope;
int r;
assert(configuration);
if (current_dns_server) {
r = dns_server_dump_configuration_to_json(current_dns_server, &current_dns_server_json);
if (r < 0)
return r;
}
SET_FOREACH(scope, dns_scopes) {
_cleanup_(sd_json_variant_unrefp) sd_json_variant *v = NULL;
r = dns_scope_to_json(scope, /* with_cache= */ false, &v);
if (r < 0)
return r;
r = sd_json_variant_append_array(&scopes_json, v);
if (r < 0)
return r;
}
LIST_FOREACH(servers, s, dns_servers) {
_cleanup_(sd_json_variant_unrefp) sd_json_variant *v = NULL;
r = dns_server_dump_configuration_to_json(s, &v);
if (r < 0)
return r;
r = sd_json_variant_append_array(&dns_servers_json, v);
if (r < 0)
return r;
}
LIST_FOREACH(domains, d, search_domains) {
_cleanup_(sd_json_variant_unrefp) sd_json_variant *v = NULL;
r = dns_search_domain_dump_to_json(d, &v);
if (r < 0)
return r;
r = sd_json_variant_append_array(&search_domains_json, v);
if (r < 0)
return r;
}
LIST_FOREACH(servers, s, fallback_dns_servers) {
_cleanup_(sd_json_variant_unrefp) sd_json_variant *v = NULL;
r = dns_server_dump_configuration_to_json(s, &v);
if (r < 0)
return r;
r = sd_json_variant_append_array(&fallback_dns_servers_json, v);
if (r < 0)
return r;
}
return sd_json_variant_append_arraybo(
configuration,
JSON_BUILD_PAIR_STRING_NON_EMPTY("ifname", ifname),
SD_JSON_BUILD_PAIR_CONDITION(ifindex > 0, "ifindex", SD_JSON_BUILD_UNSIGNED(ifindex)),
JSON_BUILD_PAIR_STRING_NON_EMPTY("delegate", delegate),
JSON_BUILD_PAIR_TRISTATE_NON_NULL("defaultRoute", default_route),
JSON_BUILD_PAIR_VARIANT_NON_NULL("currentServer", current_dns_server_json),
JSON_BUILD_PAIR_VARIANT_NON_NULL("servers", dns_servers_json),
JSON_BUILD_PAIR_VARIANT_NON_NULL("fallbackServers", fallback_dns_servers_json),
JSON_BUILD_PAIR_VARIANT_NON_NULL("searchDomains", search_domains_json),
SD_JSON_BUILD_PAIR_CONDITION(!set_isempty(negative_trust_anchors),
"negativeTrustAnchors",
JSON_BUILD_STRING_SET(negative_trust_anchors)),
JSON_BUILD_PAIR_CONDITION_BOOLEAN(dnssec_mode >= 0, "dnssecSupported", dnssec_supported),
JSON_BUILD_PAIR_STRING_NON_EMPTY("dnssec", dnssec_mode_to_string(dnssec_mode)),
JSON_BUILD_PAIR_STRING_NON_EMPTY("dnsOverTLS", dns_over_tls_mode_to_string(dns_over_tls_mode)),
JSON_BUILD_PAIR_STRING_NON_EMPTY_UNDERSCORIFY("llmnr", resolve_support_to_string(llmnr_support)),
JSON_BUILD_PAIR_STRING_NON_EMPTY_UNDERSCORIFY("mDNS", resolve_support_to_string(mdns_support)),
JSON_BUILD_PAIR_STRING_NON_EMPTY_UNDERSCORIFY("resolvConfMode", resolv_conf_mode_to_string(resolv_conf_mode)),
JSON_BUILD_PAIR_VARIANT_NON_NULL("scopes", scopes_json));
}
static int global_dns_configuration_json_append(Manager *m, sd_json_variant **configuration) {
_cleanup_set_free_ Set *scopes = NULL;
int r;
assert(m);
assert(configuration);
r = set_ensure_put(&scopes, NULL, m->unicast_scope);
if (r < 0)
return r;
return dns_configuration_json_append(
/* ifname= */ NULL,
/* ifindex= */ 0,
/* delegate= */ NULL,
/* default_route= */ -1,
manager_get_dns_server(m),
m->dns_servers,
m->fallback_dns_servers,
m->search_domains,
m->trust_anchor.negative_by_name,
scopes,
manager_get_dnssec_mode(m),
manager_dnssec_supported(m),
manager_get_dns_over_tls_mode(m),
m->llmnr_support,
m->mdns_support,
resolv_conf_mode(),
configuration);
}
static int link_dns_configuration_json_append(Link *l, sd_json_variant **configuration) {
_cleanup_set_free_ Set *scopes = NULL;
int r;
assert(l);
assert(configuration);
if (l->unicast_scope) {
r = set_ensure_put(&scopes, NULL, l->unicast_scope);
if (r < 0)
return r;
}
if (l->llmnr_ipv4_scope) {
r = set_ensure_put(&scopes, NULL, l->llmnr_ipv4_scope);
if (r < 0)
return r;
}
if (l->llmnr_ipv6_scope) {
r = set_ensure_put(&scopes, NULL, l->llmnr_ipv6_scope);
if (r < 0)
return r;
}
if (l->mdns_ipv4_scope) {
r = set_ensure_put(&scopes, NULL, l->mdns_ipv4_scope);
if (r < 0)
return r;
}
if (l->mdns_ipv6_scope) {
r = set_ensure_put(&scopes, NULL, l->mdns_ipv6_scope);
if (r < 0)
return r;
}
return dns_configuration_json_append(
l->ifname,
l->ifindex,
/* delegate= */ NULL,
link_get_default_route(l),
link_get_dns_server(l),
l->dns_servers,
/* fallback_dns_servers= */ NULL,
l->search_domains,
l->dnssec_negative_trust_anchors,
scopes,
link_get_dnssec_mode(l),
link_dnssec_supported(l),
link_get_dns_over_tls_mode(l),
link_get_llmnr_support(l),
link_get_mdns_support(l),
/* resolv_conf_mode= */ _RESOLV_CONF_MODE_INVALID,
configuration);
}
static int delegate_dns_configuration_json_append(DnsDelegate *d, sd_json_variant **configuration) {
_cleanup_set_free_ Set *scopes = NULL;
int r;
assert(d);
assert(configuration);
r = set_ensure_put(&scopes, NULL, d->scope);
if (r < 0)
return r;
return dns_configuration_json_append(
/* ifname= */ NULL,
/* ifindex= */ 0,
d->id,
d->default_route > 0, /* Defaults to false. See dns_scope_is_default_route(). */
dns_delegate_get_dns_server(d),
d->dns_servers,
/* fallback_dns_servers= */ NULL,
d->search_domains,
/* negative_trust_anchors= */ NULL,
scopes,
/* dnssec_mode= */ _DNSSEC_MODE_INVALID,
/* dnssec_supported= */ false,
/* dns_over_tls_mode= */ _DNS_OVER_TLS_MODE_INVALID,
/* llmnr_support= */ _RESOLVE_SUPPORT_INVALID,
/* mdns_support= */ _RESOLVE_SUPPORT_INVALID,
/* resolv_conf_mode= */ _RESOLV_CONF_MODE_INVALID,
configuration);
}
int manager_dump_dns_configuration_json(Manager *m, sd_json_variant **ret) {
_cleanup_(sd_json_variant_unrefp) sd_json_variant *configuration = NULL;
Link *l;
DnsDelegate *d;
int r;
assert(m);
assert(ret);
/* Global DNS configuration */
r = global_dns_configuration_json_append(m, &configuration);
if (r < 0)
return r;
/* Append configuration for each link */
HASHMAP_FOREACH(l, m->links) {
r = link_dns_configuration_json_append(l, &configuration);
if (r < 0)
return r;
}
/* Append configuration for each delegate */
HASHMAP_FOREACH(d, m->delegates) {
r = delegate_dns_configuration_json_append(d, &configuration);
if (r < 0)
return r;
}
return sd_json_buildo(ret, SD_JSON_BUILD_PAIR_VARIANT("configuration", configuration));
}
int manager_send_dns_configuration_changed(Manager *m, Link *l, bool reset) {
_cleanup_(sd_json_variant_unrefp) sd_json_variant *configuration = NULL;
int r;
assert(m);
if (set_isempty(m->varlink_dns_configuration_subscription))
return 0;
if (reset) {
dns_server_reset_accessible_all(m->dns_servers);
if (l)
dns_server_reset_accessible_all(l->dns_servers);
}
r = manager_dump_dns_configuration_json(m, &configuration);
if (r < 0)
return log_warning_errno(r, "Failed to dump DNS configuration json: %m");
if (sd_json_variant_equal(configuration, m->dns_configuration_json))
return 0;
json_variant_unref_and_replace(m->dns_configuration_json, configuration);
r = varlink_many_notify(m->varlink_dns_configuration_subscription, m->dns_configuration_json);
if (r < 0)
return log_warning_errno(r, "Failed to send DNS configuration event: %m");
return 0;
}
int manager_start_dns_configuration_monitor(Manager *m) {
Link *l;
int r;
assert(m);
assert(!m->dns_configuration_json);
assert(!m->netlink_new_route_slot);
assert(!m->netlink_del_route_slot);
dns_server_reset_accessible_all(m->dns_servers);
HASHMAP_FOREACH(l, m->links)
dns_server_reset_accessible_all(l->dns_servers);
r = manager_dump_dns_configuration_json(m, &m->dns_configuration_json);
if (r < 0)
return r;
r = sd_netlink_add_match(m->rtnl, &m->netlink_new_route_slot, RTM_NEWROUTE, manager_process_route, NULL, m, "resolve-NEWROUTE");
if (r < 0)
return r;
r = sd_netlink_add_match(m->rtnl, &m->netlink_del_route_slot, RTM_DELROUTE, manager_process_route, NULL, m, "resolve-DELROUTE");
if (r < 0)
return r;
return 0;
}
void manager_stop_dns_configuration_monitor(Manager *m) {
assert(m);
m->dns_configuration_json = sd_json_variant_unref(m->dns_configuration_json);
m->netlink_new_route_slot = sd_netlink_slot_unref(m->netlink_new_route_slot);
m->netlink_del_route_slot = sd_netlink_slot_unref(m->netlink_del_route_slot);
}
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