| /* SPDX-License-Identifier: LGPL-2.1-or-later */ |
| |
| #include <fcntl.h> |
| #include <netinet/in.h> |
| #include <poll.h> |
| #include <sys/ioctl.h> |
| #include <sys/stat.h> |
| #include <sys/types.h> |
| #include <unistd.h> |
| |
| #include "af-list.h" |
| #include "alloc-util.h" |
| #include "bus-polkit.h" |
| #include "dirent-util.h" |
| #include "dns-domain.h" |
| #include "fd-util.h" |
| #include "fileio.h" |
| #include "hostname-util.h" |
| #include "idn-util.h" |
| #include "io-util.h" |
| #include "missing_network.h" |
| #include "missing_socket.h" |
| #include "netlink-util.h" |
| #include "ordered-set.h" |
| #include "parse-util.h" |
| #include "random-util.h" |
| #include "resolved-bus.h" |
| #include "resolved-conf.h" |
| #include "resolved-dns-stub.h" |
| #include "resolved-dnssd.h" |
| #include "resolved-etc-hosts.h" |
| #include "resolved-llmnr.h" |
| #include "resolved-manager.h" |
| #include "resolved-mdns.h" |
| #include "resolved-resolv-conf.h" |
| #include "resolved-util.h" |
| #include "resolved-varlink.h" |
| #include "socket-util.h" |
| #include "string-table.h" |
| #include "string-util.h" |
| #include "utf8.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 = userdata; |
| uint16_t type; |
| Link *l; |
| int ifindex, r; |
| |
| assert(rtnl); |
| assert(m); |
| 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); |
| } |
| |
| break; |
| } |
| |
| 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 = userdata; |
| union in_addr_union address; |
| uint16_t type; |
| int r, ifindex, family; |
| LinkAddress *a; |
| Link *l; |
| |
| assert(rtnl); |
| assert(mm); |
| assert(m); |
| |
| 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: |
| 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); |
| 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; |
| } |
| |
| return 0; |
| |
| fail: |
| log_warning_errno(r, "Failed to process RTNL address message: %m"); |
| return 0; |
| } |
| |
| static int manager_rtnl_listen(Manager *m) { |
| _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *req = NULL, *reply = NULL; |
| sd_netlink_message *i; |
| 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_request_dump(req, true); |
| if (r < 0) |
| return r; |
| |
| r = sd_netlink_call(m->rtnl, req, 0, &reply); |
| if (r < 0) |
| return r; |
| |
| for (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_request_dump(req, true); |
| if (r < 0) |
| return r; |
| |
| r = sd_netlink_call(m->rtnl, req, 0, &reply); |
| if (r < 0) |
| return r; |
| |
| for (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 *s, int fd, uint32_t revents, void *userdata) { |
| Manager *m = userdata; |
| Link *l; |
| int r; |
| |
| assert(m); |
| |
| 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"); |
| |
| 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 = userdata; |
| |
| assert(m); |
| |
| /* 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) { |
| _cleanup_close_ int fd = -1; |
| int r; |
| |
| assert(m); |
| |
| m->clock_change_event_source = sd_event_source_disable_unref(m->clock_change_event_source); |
| |
| fd = time_change_fd(); |
| if (fd < 0) |
| return log_error_errno(fd, "Failed to allocate clock change timer fd: %m"); |
| |
| r = sd_event_add_io(m->event, &m->clock_change_event_source, fd, EPOLLIN, on_clock_change, m); |
| if (r < 0) |
| return log_error_errno(r, "Failed to create clock change event source: %m"); |
| |
| r = sd_event_source_set_io_fd_own(m->clock_change_event_source, true); |
| if (r < 0) |
| return log_error_errno(r, "Failed to pass ownership of clock fd to event source: %m"); |
| TAKE_FD(fd); |
| |
| (void) sd_event_source_set_description(m->clock_change_event_source, "clock-change"); |
| |
| 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]; |
| 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 = userdata; |
| bool llmnr_hostname_changed; |
| int r; |
| |
| assert(m); |
| |
| 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) { |
| if (r == -EPERM) |
| /* kernels prior to 3.2 don't support polling this file. Ignore the failure. */ |
| m->hostname_fd = safe_close(m->hostname_fd); |
| else |
| 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_free_ char *buffer = NULL; |
| _cleanup_fclose_ FILE *f = NULL; |
| Manager *m = userdata; |
| DnsServer *server; |
| size_t size = 0; |
| DnsScope *scope; |
| Link *l; |
| |
| assert(s); |
| assert(si); |
| assert(m); |
| |
| f = open_memstream_unlocked(&buffer, &size); |
| 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); |
| |
| if (fflush_and_check(f) < 0) |
| return log_oom(); |
| |
| log_dump(LOG_INFO, buffer); |
| return 0; |
| } |
| |
| static int manager_sigusr2(sd_event_source *s, const struct signalfd_siginfo *si, void *userdata) { |
| Manager *m = userdata; |
| |
| assert(s); |
| assert(si); |
| assert(m); |
| |
| 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 = userdata; |
| |
| assert(s); |
| assert(si); |
| assert(m); |
| |
| manager_reset_server_features(m); |
| 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 = -1, |
| .llmnr_ipv6_udp_fd = -1, |
| .llmnr_ipv4_tcp_fd = -1, |
| .llmnr_ipv6_tcp_fd = -1, |
| .mdns_ipv4_fd = -1, |
| .mdns_ipv6_fd = -1, |
| .hostname_fd = -1, |
| |
| .llmnr_support = DEFAULT_LLMNR_MODE, |
| .mdns_support = DEFAULT_MDNS_MODE, |
| .dnssec_mode = DEFAULT_DNSSEC_MODE, |
| .dns_over_tls_mode = DEFAULT_DNS_OVER_TLS_MODE, |
| .enable_cache = DNS_CACHE_MODE_YES, |
| .dns_stub_listener_mode = DNS_STUB_LISTENER_YES, |
| .read_resolv_conf = true, |
| .need_builtin_fallbacks = true, |
| .etc_hosts_last = USEC_INFINITY, |
| .read_etc_hosts = true, |
| }; |
| |
| 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: %m"); |
| |
| #if ENABLE_DNS_OVER_TLS |
| r = dnstls_manager_init(m); |
| if (r < 0) |
| return r; |
| #endif |
| |
| r = sd_event_default(&m->event); |
| if (r < 0) |
| return r; |
| |
| (void) sd_event_add_signal(m->event, NULL, SIGTERM, NULL, NULL); |
| (void) sd_event_add_signal(m->event, NULL, SIGINT, NULL, NULL); |
| |
| (void) sd_event_set_watchdog(m->event, true); |
| |
| r = manager_watch_hostname(m); |
| if (r < 0) |
| return r; |
| |
| r = dnssd_load(m); |
| if (r < 0) |
| log_warning_errno(r, "Failed to load DNS-SD configuration files: %m"); |
| |
| r = dns_scope_new(m, &m->unicast_scope, 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_connect_bus(m); |
| if (r < 0) |
| return r; |
| |
| (void) sd_event_add_signal(m->event, &m->sigusr1_event_source, SIGUSR1, manager_sigusr1, m); |
| (void) sd_event_add_signal(m->event, &m->sigusr2_event_source, SIGUSR2, manager_sigusr2, m); |
| (void) sd_event_add_signal(m->event, &m->sigrtmin1_event_source, SIGRTMIN+1, manager_sigrtmin1, 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) { |
| Link *l; |
| DnssdService *s; |
| |
| 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); |
| |
| while ((l = hashmap_first(m->links))) |
| link_free(l); |
| |
| while (m->dns_queries) |
| dns_query_free(m->dns_queries); |
| |
| m->stub_queries_by_packet = hashmap_free(m->stub_queries_by_packet); |
| |
| 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 |
| |
| hashmap_free(m->links); |
| hashmap_free(m->dns_transactions); |
| |
| sd_event_source_unref(m->network_event_source); |
| sd_network_monitor_unref(m->network_monitor); |
| |
| sd_netlink_unref(m->rtnl); |
| sd_event_source_unref(m->rtnl_event_source); |
| sd_event_source_unref(m->clock_change_event_source); |
| |
| manager_llmnr_stop(m); |
| manager_mdns_stop(m); |
| manager_dns_stub_stop(m); |
| manager_varlink_done(m); |
| |
| manager_socket_graveyard_clear(m); |
| |
| ordered_set_free(m->dns_extra_stub_listeners); |
| |
| bus_verify_polkit_async_registry_free(m->polkit_registry); |
| |
| sd_bus_flush_close_unref(m->bus); |
| |
| sd_event_source_unref(m->sigusr1_event_source); |
| sd_event_source_unref(m->sigusr2_event_source); |
| sd_event_source_unref(m->sigrtmin1_event_source); |
| |
| 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); |
| |
| while ((s = hashmap_first(m->dnssd_services))) |
| dnssd_service_free(s); |
| hashmap_free(m->dnssd_services); |
| |
| dns_trust_anchor_flush(&m->trust_anchor); |
| manager_etc_hosts_flush(m); |
| |
| 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); |
| 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 (IN_SET(l, -EAGAIN, -EINTR)) |
| return 0; |
| if (l <= 0) |
| return l; |
| |
| assert(!(mh.msg_flags & MSG_TRUNC)); |
| |
| 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_or_monotonic()); |
| |
| 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 = (struct in6_pktinfo*) CMSG_DATA(cmsg); |
| |
| if (p->ifindex <= 0) |
| p->ifindex = i->ipi6_ifindex; |
| |
| p->destination.in6 = i->ipi6_addr; |
| break; |
| } |
| |
| case IPV6_HOPLIMIT: |
| p->ttl = *(int *) CMSG_DATA(cmsg); |
| break; |
| |
| case IPV6_RECVFRAGSIZE: |
| p->fragsize = *(int *) CMSG_DATA(cmsg); |
| break; |
| } |
| } else if (cmsg->cmsg_level == IPPROTO_IP) { |
| assert(p->family == AF_INET); |
| |
| switch (cmsg->cmsg_type) { |
| |
| case IP_PKTINFO: { |
| struct in_pktinfo *i = (struct in_pktinfo*) CMSG_DATA(cmsg); |
| |
| if (p->ifindex <= 0) |
| p->ifindex = i->ipi_ifindex; |
| |
| p->destination.in = i->ipi_addr; |
| break; |
| } |
| |
| case IP_TTL: |
| p->ttl = *(int *) CMSG_DATA(cmsg); |
| break; |
| |
| case IP_RECVFRAGSIZE: |
| p->fragsize = *(int *) CMSG_DATA(cmsg); |
| 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=%i, fragsize=%zu", |
| dns_protocol_to_string(protocol), p->size, p->ifindex, p->ttl, p->fragsize); |
| |
| *ret = TAKE_PTR(p); |
| return 1; |
| } |
| |
| static int sendmsg_loop(int fd, struct msghdr *mh, int flags) { |
| int r; |
| |
| assert(fd >= 0); |
| assert(mh); |
| |
| 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, SEND_TIMEOUT_USEC); |
| if (r < 0) |
| return r; |
| if (r == 0) |
| return -ETIMEDOUT; |
| } |
| } |
| |
| static int write_loop(int fd, void *message, size_t length) { |
| int r; |
| |
| assert(fd >= 0); |
| assert(message); |
| |
| 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, SEND_TIMEOUT_USEC); |
| 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 = (struct in_pktinfo*) CMSG_DATA(cmsg); |
| 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 = (struct in6_pktinfo*) CMSG_DATA(cmsg); |
| pi->ipi6_ifindex = ifindex; |
| |
| if (source) |
| pi->ipi6_addr = *source; |
| } |
| |
| return sendmsg_loop(fd, &mh, 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); |
| |
| log_debug("Sending %s%s packet with id %" PRIu16 " on interface %i/%s of size %zu.", |
| DNS_PACKET_TC(p) ? "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; |
| DnssdService *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_services) |
| if (dnssd_update_rrs(s) < 0) |
| log_warning("Failed to refresh DNS-SD service '%s'", s->name); |
| |
| 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; |
| |
| p = strchr(old, 0); |
| assert(p); |
| |
| while (p > old) { |
| if (!strchr(DIGITS, 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(Manager *m, DnsPacket *p) { |
| Link *l; |
| |
| assert(m); |
| assert(p); |
| |
| l = hashmap_get(m->links, INT_TO_PTR(p->ifindex)); |
| if (!l) |
| return NULL; |
| |
| switch (p->protocol) { |
| case DNS_PROTOCOL_LLMNR: |
| if (p->family == AF_INET) |
| return l->llmnr_ipv4_scope; |
| else if (p->family == AF_INET6) |
| return l->llmnr_ipv6_scope; |
| |
| break; |
| |
| case DNS_PROTOCOL_MDNS: |
| if (p->family == AF_INET) |
| return l->mdns_ipv4_scope; |
| else if (p->family == AF_INET6) |
| return l->mdns_ipv6_scope; |
| |
| break; |
| |
| default: |
| break; |
| } |
| |
| return NULL; |
| } |
| |
| void manager_verify_all(Manager *m) { |
| DnsScope *s; |
| |
| 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 **dns) { |
| DnsServer *s; |
| Link *l; |
| int r; |
| |
| assert(m); |
| assert(dns); |
| |
| r = ordered_set_ensure_allocated(dns, &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(*dns, 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(*dns, s); |
| if (r == -EEXIST) |
| continue; |
| if (r < 0) |
| return r; |
| } |
| } |
| |
| /* If we found nothing, add the fallback servers */ |
| if (ordered_set_isempty(*dns)) { |
| LIST_FOREACH(servers, s, m->fallback_dns_servers) { |
| r = ordered_set_put(*dns, 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) { |
| DnsSearchDomain *d; |
| Link *l; |
| 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; |
| } |
| |
| 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) { |
| DnsScope *scope; |
| |
| assert(m); |
| |
| LIST_FOREACH(scopes, scope, m->dns_scopes) |
| dns_cache_flush(&scope->cache); |
| |
| log_full(log_level, "Flushed all caches."); |
| } |
| |
| void manager_reset_server_features(Manager *m) { |
| Link *l; |
| |
| dns_server_reset_features_all(m->dns_servers); |
| dns_server_reset_features_all(m->fallback_dns_servers); |
| |
| HASHMAP_FOREACH(l, m->links) |
| dns_server_reset_features_all(l->dns_servers); |
| |
| log_info("Resetting learnt feature levels on all servers."); |
| } |
| |
| void manager_cleanup_saved_user(Manager *m) { |
| _cleanup_closedir_ DIR *d = NULL; |
| struct dirent *de; |
| |
| 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")) { |
| _cleanup_free_ char *p = NULL; |
| 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: |
| p = path_join("/run/systemd/resolve/netif", de->d_name); |
| if (!p) { |
| log_oom(); |
| return; |
| } |
| |
| (void) unlink(p); |
| } |
| } |
| |
| bool manager_next_dnssd_names(Manager *m) { |
| DnssdService *s; |
| bool tried = false; |
| int r; |
| |
| assert(m); |
| |
| HASHMAP_FOREACH(s, m->dnssd_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->name); |
| 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) { |
| r = socket_get_family(fd, &af); |
| if (r < 0) |
| return r; |
| } |
| |
| 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; |
| } |
| } |
