| /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ |
| |
| /*** |
| This file is part of systemd. |
| |
| Copyright 2014 Tom Gundersen <teg@jklm.no> |
| |
| systemd is free software; you can redistribute it and/or modify it |
| under the terms of the GNU Lesser General Public License as published by |
| the Free Software Foundation; either version 2.1 of the License, or |
| (at your option) any later version. |
| |
| systemd is distributed in the hope that it will be useful, but |
| WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| Lesser General Public License for more details. |
| |
| You should have received a copy of the GNU Lesser General Public License |
| along with systemd; If not, see <http://www.gnu.org/licenses/>. |
| ***/ |
| |
| #include <resolv.h> |
| #include <sys/ioctl.h> |
| #include <poll.h> |
| #include <netinet/in.h> |
| |
| #include "netlink-util.h" |
| #include "network-internal.h" |
| #include "socket-util.h" |
| #include "af-list.h" |
| #include "utf8.h" |
| #include "fileio-label.h" |
| #include "ordered-set.h" |
| #include "random-util.h" |
| #include "hostname-util.h" |
| |
| #include "dns-domain.h" |
| #include "resolved-conf.h" |
| #include "resolved-bus.h" |
| #include "resolved-manager.h" |
| #include "resolved-llmnr.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_update_rtnl(l, mm); |
| if (r < 0) |
| goto fail; |
| |
| r = link_update_monitor(l); |
| if (r < 0) |
| goto fail; |
| |
| if (is_new) |
| log_debug("Found new link %i/%s", ifindex, l->name); |
| |
| break; |
| } |
| |
| case RTM_DELLINK: |
| if (l) { |
| log_debug("Removing link %i/%s", l->ifindex, l->name); |
| 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_netlink_message_unref_ 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, 0); |
| if (r < 0) |
| return r; |
| |
| r = sd_netlink_add_match(m->rtnl, RTM_NEWLINK, manager_process_link, m); |
| if (r < 0) |
| return r; |
| |
| r = sd_netlink_add_match(m->rtnl, RTM_DELLINK, manager_process_link, m); |
| if (r < 0) |
| return r; |
| |
| r = sd_netlink_add_match(m->rtnl, RTM_NEWADDR, manager_process_address, m); |
| if (r < 0) |
| return r; |
| |
| r = sd_netlink_add_match(m->rtnl, RTM_DELADDR, manager_process_address, m); |
| 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; |
| Iterator i; |
| Link *l; |
| int r; |
| |
| assert(m); |
| |
| sd_network_monitor_flush(m->network_monitor); |
| |
| HASHMAP_FOREACH(l, m->links, i) { |
| r = link_update_monitor(l); |
| if (r < 0) |
| log_warning_errno(r, "Failed to update monitor information for %i: %m", l->ifindex); |
| } |
| |
| r = manager_write_resolv_conf(m); |
| if (r < 0) |
| log_warning_errno(r, "Could not update resolv.conf: %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; |
| |
| return 0; |
| } |
| |
| static int determine_hostname(char **llmnr_hostname, char **mdns_hostname) { |
| _cleanup_free_ char *h = NULL, *n = NULL; |
| char label[DNS_LABEL_MAX]; |
| const char *p; |
| int r, k; |
| |
| assert(llmnr_hostname); |
| assert(mdns_hostname); |
| |
| /* Extract and normalize the first label of the locally |
| * configured hostname, and check it's not "localhost". */ |
| |
| h = gethostname_malloc(); |
| if (!h) |
| return log_oom(); |
| |
| p = h; |
| r = dns_label_unescape(&p, label, sizeof(label)); |
| if (r < 0) |
| return log_error_errno(r, "Failed to unescape host name: %m"); |
| if (r == 0) { |
| log_error("Couldn't find a single label in hosntame."); |
| return -EINVAL; |
| } |
| |
| k = dns_label_undo_idna(label, r, label, sizeof(label)); |
| if (k < 0) |
| return log_error_errno(k, "Failed to undo IDNA: %m"); |
| if (k > 0) |
| r = k; |
| |
| if (!utf8_is_valid(label)) { |
| log_error("System hostname is not UTF-8 clean."); |
| return -EINVAL; |
| } |
| |
| r = dns_label_escape(label, r, &n); |
| if (r < 0) |
| return log_error_errno(r, "Failed to escape host name: %m"); |
| |
| if (is_localhost(n)) { |
| log_debug("System hostname is 'localhost', ignoring."); |
| return -EINVAL; |
| } |
| |
| r = dns_name_concat(n, "local", mdns_hostname); |
| if (r < 0) |
| return log_error_errno(r, "Failed to determine mDNS hostname: %m"); |
| |
| *llmnr_hostname = n; |
| n = NULL; |
| |
| return 0; |
| } |
| |
| static int on_hostname_change(sd_event_source *es, int fd, uint32_t revents, void *userdata) { |
| _cleanup_free_ char *llmnr_hostname = NULL, *mdns_hostname = NULL; |
| Manager *m = userdata; |
| int r; |
| |
| assert(m); |
| |
| r = determine_hostname(&llmnr_hostname, &mdns_hostname); |
| if (r < 0) |
| return 0; /* ignore invalid hostnames */ |
| |
| if (streq(llmnr_hostname, m->llmnr_hostname) && streq(mdns_hostname, m->mdns_hostname)) |
| return 0; |
| |
| log_info("System hostname changed to '%s'.", llmnr_hostname); |
| |
| free(m->llmnr_hostname); |
| free(m->mdns_hostname); |
| |
| m->llmnr_hostname = llmnr_hostname; |
| m->mdns_hostname = mdns_hostname; |
| |
| llmnr_hostname = mdns_hostname = NULL; |
| |
| manager_refresh_rrs(m); |
| |
| 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_NDELAY|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"); |
| } |
| |
| r = determine_hostname(&m->llmnr_hostname, &m->mdns_hostname); |
| if (r < 0) { |
| log_info("Defaulting to hostname 'linux'."); |
| m->llmnr_hostname = strdup("linux"); |
| if (!m->llmnr_hostname) |
| return log_oom(); |
| |
| m->mdns_hostname = strdup("linux.local"); |
| if (!m->mdns_hostname) |
| return log_oom(); |
| } else |
| log_info("Using system hostname '%s'.", m->llmnr_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; |
| size_t size = 0; |
| DnsScope *scope; |
| |
| assert(s); |
| assert(si); |
| assert(m); |
| |
| f = open_memstream(&buffer, &size); |
| if (!f) |
| return log_oom(); |
| |
| LIST_FOREACH(scopes, scope, m->dns_scopes) |
| dns_scope_dump(scope, f); |
| |
| if (fflush_and_check(f) < 0) |
| return log_oom(); |
| |
| log_dump(LOG_INFO, buffer); |
| return 0; |
| } |
| |
| int manager_new(Manager **ret) { |
| _cleanup_(manager_freep) Manager *m = NULL; |
| int r; |
| |
| assert(ret); |
| |
| m = new0(Manager, 1); |
| if (!m) |
| return -ENOMEM; |
| |
| m->llmnr_ipv4_udp_fd = m->llmnr_ipv6_udp_fd = -1; |
| m->llmnr_ipv4_tcp_fd = m->llmnr_ipv6_tcp_fd = -1; |
| m->hostname_fd = -1; |
| |
| m->llmnr_support = SUPPORT_YES; |
| m->read_resolv_conf = true; |
| |
| r = manager_parse_dns_server(m, DNS_SERVER_FALLBACK, DNS_SERVERS); |
| if (r < 0) |
| return r; |
| |
| r = sd_event_default(&m->event); |
| if (r < 0) |
| return r; |
| |
| sd_event_add_signal(m->event, NULL, SIGTERM, NULL, NULL); |
| sd_event_add_signal(m->event, NULL, SIGINT, NULL, NULL); |
| |
| sd_event_set_watchdog(m->event, true); |
| |
| r = manager_watch_hostname(m); |
| if (r < 0) |
| return r; |
| |
| 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_connect_bus(m); |
| if (r < 0) |
| return r; |
| |
| (void) sd_event_add_signal(m->event, &m->sigusr1_event_source, SIGUSR1, manager_sigusr1, m); |
| |
| *ret = m; |
| m = NULL; |
| |
| return 0; |
| } |
| |
| int manager_start(Manager *m) { |
| int r; |
| |
| assert(m); |
| |
| r = manager_llmnr_start(m); |
| if (r < 0) |
| return r; |
| |
| return 0; |
| } |
| |
| Manager *manager_free(Manager *m) { |
| Link *l; |
| |
| if (!m) |
| return NULL; |
| |
| while ((l = hashmap_first(m->links))) |
| link_free(l); |
| |
| while (m->dns_queries) |
| dns_query_free(m->dns_queries); |
| |
| manager_flush_dns_servers(m, DNS_SERVER_SYSTEM); |
| manager_flush_dns_servers(m, DNS_SERVER_FALLBACK); |
| |
| dns_scope_free(m->unicast_scope); |
| |
| hashmap_free(m->links); |
| hashmap_free(m->dns_transactions); |
| |
| sd_event_source_unref(m->network_event_source); |
| sd_network_monitor_unref(m->network_monitor); |
| |
| manager_llmnr_stop(m); |
| |
| sd_bus_slot_unref(m->prepare_for_sleep_slot); |
| sd_event_source_unref(m->bus_retry_event_source); |
| sd_bus_unref(m->bus); |
| |
| sd_event_source_unref(m->sigusr1_event_source); |
| |
| sd_event_unref(m->event); |
| |
| dns_resource_key_unref(m->llmnr_host_ipv4_key); |
| dns_resource_key_unref(m->llmnr_host_ipv6_key); |
| |
| sd_event_source_unref(m->hostname_event_source); |
| safe_close(m->hostname_fd); |
| free(m->llmnr_hostname); |
| free(m->mdns_hostname); |
| |
| free(m); |
| |
| return NULL; |
| } |
| |
| int manager_read_resolv_conf(Manager *m) { |
| _cleanup_fclose_ FILE *f = NULL; |
| struct stat st, own; |
| char line[LINE_MAX]; |
| DnsServer *s, *nx; |
| usec_t t; |
| int r; |
| |
| assert(m); |
| |
| /* Reads the system /etc/resolv.conf, if it exists and is not |
| * symlinked to our own resolv.conf instance */ |
| |
| if (!m->read_resolv_conf) |
| return 0; |
| |
| r = stat("/etc/resolv.conf", &st); |
| if (r < 0) { |
| if (errno != ENOENT) |
| log_warning_errno(errno, "Failed to open /etc/resolv.conf: %m"); |
| r = -errno; |
| goto clear; |
| } |
| |
| /* Have we already seen the file? */ |
| t = timespec_load(&st.st_mtim); |
| if (t == m->resolv_conf_mtime) |
| return 0; |
| |
| m->resolv_conf_mtime = t; |
| |
| /* Is it symlinked to our own file? */ |
| if (stat("/run/systemd/resolve/resolv.conf", &own) >= 0 && |
| st.st_dev == own.st_dev && |
| st.st_ino == own.st_ino) { |
| r = 0; |
| goto clear; |
| } |
| |
| f = fopen("/etc/resolv.conf", "re"); |
| if (!f) { |
| if (errno != ENOENT) |
| log_warning_errno(errno, "Failed to open /etc/resolv.conf: %m"); |
| r = -errno; |
| goto clear; |
| } |
| |
| if (fstat(fileno(f), &st) < 0) { |
| log_error_errno(errno, "Failed to stat open file: %m"); |
| r = -errno; |
| goto clear; |
| } |
| |
| LIST_FOREACH(servers, s, m->dns_servers) |
| s->marked = true; |
| |
| FOREACH_LINE(line, f, r = -errno; goto clear) { |
| union in_addr_union address; |
| int family; |
| char *l; |
| const char *a; |
| |
| truncate_nl(line); |
| |
| l = strstrip(line); |
| if (*l == '#' || *l == ';') |
| continue; |
| |
| a = first_word(l, "nameserver"); |
| if (!a) |
| continue; |
| |
| r = in_addr_from_string_auto(a, &family, &address); |
| if (r < 0) { |
| log_warning("Failed to parse name server %s.", a); |
| continue; |
| } |
| |
| LIST_FOREACH(servers, s, m->dns_servers) |
| if (s->family == family && in_addr_equal(family, &s->address, &address) > 0) |
| break; |
| |
| if (s) |
| s->marked = false; |
| else { |
| r = dns_server_new(m, NULL, DNS_SERVER_SYSTEM, NULL, family, &address); |
| if (r < 0) |
| goto clear; |
| } |
| } |
| |
| LIST_FOREACH_SAFE(servers, s, nx, m->dns_servers) |
| if (s->marked) { |
| LIST_REMOVE(servers, m->dns_servers, s); |
| dns_server_unref(s); |
| } |
| |
| /* Whenever /etc/resolv.conf changes, start using the first |
| * DNS server of it. This is useful to deal with broken |
| * network managing implementations (like NetworkManager), |
| * that when connecting to a VPN place both the VPN DNS |
| * servers and the local ones in /etc/resolv.conf. Without |
| * resetting the DNS server to use back to the first entry we |
| * will continue to use the local one thus being unable to |
| * resolve VPN domains. */ |
| manager_set_dns_server(m, m->dns_servers); |
| |
| return 0; |
| |
| clear: |
| while (m->dns_servers) { |
| s = m->dns_servers; |
| |
| LIST_REMOVE(servers, m->dns_servers, s); |
| dns_server_unref(s); |
| } |
| |
| return r; |
| } |
| |
| static void write_resolv_conf_server(DnsServer *s, FILE *f, unsigned *count) { |
| _cleanup_free_ char *t = NULL; |
| int r; |
| |
| assert(s); |
| assert(f); |
| assert(count); |
| |
| r = in_addr_to_string(s->family, &s->address, &t); |
| if (r < 0) { |
| log_warning_errno(r, "Invalid DNS address. Ignoring: %m"); |
| return; |
| } |
| |
| if (*count == MAXNS) |
| fputs("# Too many DNS servers configured, the following entries may be ignored.\n", f); |
| |
| fprintf(f, "nameserver %s\n", t); |
| (*count) ++; |
| } |
| |
| static void write_resolv_conf_search( |
| const char *domain, FILE *f, |
| unsigned *count, |
| unsigned *length) { |
| |
| assert(domain); |
| assert(f); |
| assert(length); |
| |
| if (*count >= MAXDNSRCH || |
| *length + strlen(domain) > 256) { |
| if (*count == MAXDNSRCH) |
| fputs(" # Too many search domains configured, remaining ones ignored.", f); |
| if (*length <= 256) |
| fputs(" # Total length of all search domains is too long, remaining ones ignored.", f); |
| |
| return; |
| } |
| |
| fprintf(f, " %s", domain); |
| |
| (*length) += strlen(domain); |
| (*count) ++; |
| } |
| |
| static int write_resolv_conf_contents(FILE *f, OrderedSet *dns, OrderedSet *domains) { |
| Iterator i; |
| |
| fputs("# This file is managed by systemd-resolved(8). Do not edit.\n#\n" |
| "# Third party programs must not access this file directly, but\n" |
| "# only through the symlink at /etc/resolv.conf. To manage\n" |
| "# resolv.conf(5) in a different way, replace the symlink by a\n" |
| "# static file or a different symlink.\n\n", f); |
| |
| if (ordered_set_isempty(dns)) |
| fputs("# No DNS servers known.\n", f); |
| else { |
| DnsServer *s; |
| unsigned count = 0; |
| |
| ORDERED_SET_FOREACH(s, dns, i) |
| write_resolv_conf_server(s, f, &count); |
| } |
| |
| if (!ordered_set_isempty(domains)) { |
| unsigned length = 0, count = 0; |
| char *domain; |
| |
| fputs("search", f); |
| ORDERED_SET_FOREACH(domain, domains, i) |
| write_resolv_conf_search(domain, f, &count, &length); |
| fputs("\n", f); |
| } |
| |
| return fflush_and_check(f); |
| } |
| |
| int manager_write_resolv_conf(Manager *m) { |
| static const char path[] = "/run/systemd/resolve/resolv.conf"; |
| _cleanup_free_ char *temp_path = NULL; |
| _cleanup_fclose_ FILE *f = NULL; |
| _cleanup_ordered_set_free_ OrderedSet *dns = NULL, *domains = NULL; |
| DnsServer *s; |
| Iterator i; |
| Link *l; |
| int r; |
| |
| assert(m); |
| |
| /* Read the system /etc/resolv.conf first */ |
| manager_read_resolv_conf(m); |
| |
| /* Add the full list to a set, to filter out duplicates */ |
| dns = ordered_set_new(&dns_server_hash_ops); |
| if (!dns) |
| return -ENOMEM; |
| |
| domains = ordered_set_new(&dns_name_hash_ops); |
| if (!domains) |
| return -ENOMEM; |
| |
| /* First add the system-wide servers */ |
| 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 and domains */ |
| HASHMAP_FOREACH(l, m->links, i) { |
| char **domain; |
| |
| LIST_FOREACH(servers, s, l->dns_servers) { |
| r = ordered_set_put(dns, s); |
| if (r == -EEXIST) |
| continue; |
| if (r < 0) |
| return r; |
| } |
| |
| if (!l->unicast_scope) |
| continue; |
| |
| STRV_FOREACH(domain, l->unicast_scope->domains) { |
| r = ordered_set_put(domains, *domain); |
| 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; |
| } |
| } |
| |
| r = fopen_temporary_label(path, path, &f, &temp_path); |
| if (r < 0) |
| return r; |
| |
| fchmod(fileno(f), 0644); |
| |
| r = write_resolv_conf_contents(f, dns, domains); |
| if (r < 0) |
| goto fail; |
| |
| if (rename(temp_path, path) < 0) { |
| r = -errno; |
| goto fail; |
| } |
| |
| return 0; |
| |
| fail: |
| (void) unlink(path); |
| (void) unlink(temp_path); |
| return r; |
| } |
| |
| int manager_recv(Manager *m, int fd, DnsProtocol protocol, DnsPacket **ret) { |
| _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL; |
| union { |
| struct cmsghdr header; /* For alignment */ |
| uint8_t buffer[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 msghdr mh = {}; |
| struct cmsghdr *cmsg; |
| struct iovec iov; |
| int ms = 0, r; |
| ssize_t l; |
| |
| assert(m); |
| assert(fd >= 0); |
| assert(ret); |
| |
| r = ioctl(fd, FIONREAD, &ms); |
| if (r < 0) |
| return -errno; |
| if (ms < 0) |
| return -EIO; |
| |
| r = dns_packet_new(&p, protocol, ms); |
| if (r < 0) |
| return r; |
| |
| iov.iov_base = DNS_PACKET_DATA(p); |
| iov.iov_len = p->allocated; |
| |
| mh.msg_name = &sa.sa; |
| mh.msg_namelen = sizeof(sa); |
| mh.msg_iov = &iov; |
| mh.msg_iovlen = 1; |
| mh.msg_control = &control; |
| mh.msg_controllen = sizeof(control); |
| |
| l = recvmsg(fd, &mh, 0); |
| if (l < 0) { |
| if (errno == EAGAIN || errno == EINTR) |
| return 0; |
| |
| return -errno; |
| } |
| |
| if (l <= 0) |
| return -EIO; |
| |
| assert(!(mh.msg_flags & MSG_CTRUNC)); |
| 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; |
| |
| 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; |
| |
| } |
| } 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; |
| } |
| } |
| } |
| |
| /* 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); |
| } |
| |
| *ret = p; |
| p = NULL; |
| |
| 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 packet with id %u", DNS_PACKET_QR(p) ? "response" : "query", DNS_PACKET_ID(p)); |
| |
| 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 *addr, uint16_t port, DnsPacket *p) { |
| union sockaddr_union sa = { |
| .in.sin_family = AF_INET, |
| }; |
| union { |
| struct cmsghdr header; /* For alignment */ |
| uint8_t buffer[CMSG_SPACE(sizeof(struct in_pktinfo))]; |
| } control; |
| struct msghdr mh = {}; |
| struct iovec iov; |
| |
| assert(m); |
| assert(fd >= 0); |
| assert(addr); |
| assert(port > 0); |
| assert(p); |
| |
| iov.iov_base = DNS_PACKET_DATA(p); |
| iov.iov_len = p->size; |
| |
| sa.in.sin_addr = *addr; |
| sa.in.sin_port = htobe16(port), |
| |
| mh.msg_iov = &iov; |
| mh.msg_iovlen = 1; |
| mh.msg_name = &sa.sa; |
| mh.msg_namelen = sizeof(sa.in); |
| |
| if (ifindex > 0) { |
| struct cmsghdr *cmsg; |
| struct in_pktinfo *pi; |
| |
| zero(control); |
| |
| mh.msg_control = &control; |
| mh.msg_controllen = CMSG_LEN(sizeof(struct in_pktinfo)); |
| |
| cmsg = CMSG_FIRSTHDR(&mh); |
| cmsg->cmsg_len = mh.msg_controllen; |
| cmsg->cmsg_level = IPPROTO_IP; |
| cmsg->cmsg_type = IP_PKTINFO; |
| |
| pi = (struct in_pktinfo*) CMSG_DATA(cmsg); |
| pi->ipi_ifindex = ifindex; |
| } |
| |
| return sendmsg_loop(fd, &mh, 0); |
| } |
| |
| static int manager_ipv6_send(Manager *m, int fd, int ifindex, const struct in6_addr *addr, uint16_t port, DnsPacket *p) { |
| union sockaddr_union sa = { |
| .in6.sin6_family = AF_INET6, |
| }; |
| union { |
| struct cmsghdr header; /* For alignment */ |
| uint8_t buffer[CMSG_SPACE(sizeof(struct in6_pktinfo))]; |
| } control; |
| struct msghdr mh = {}; |
| struct iovec iov; |
| |
| assert(m); |
| assert(fd >= 0); |
| assert(addr); |
| assert(port > 0); |
| assert(p); |
| |
| iov.iov_base = DNS_PACKET_DATA(p); |
| iov.iov_len = p->size; |
| |
| sa.in6.sin6_addr = *addr; |
| sa.in6.sin6_port = htobe16(port), |
| sa.in6.sin6_scope_id = ifindex; |
| |
| mh.msg_iov = &iov; |
| mh.msg_iovlen = 1; |
| mh.msg_name = &sa.sa; |
| mh.msg_namelen = sizeof(sa.in6); |
| |
| if (ifindex > 0) { |
| struct cmsghdr *cmsg; |
| struct in6_pktinfo *pi; |
| |
| zero(control); |
| |
| mh.msg_control = &control; |
| mh.msg_controllen = CMSG_LEN(sizeof(struct in6_pktinfo)); |
| |
| cmsg = CMSG_FIRSTHDR(&mh); |
| cmsg->cmsg_len = mh.msg_controllen; |
| cmsg->cmsg_level = IPPROTO_IPV6; |
| cmsg->cmsg_type = IPV6_PKTINFO; |
| |
| pi = (struct in6_pktinfo*) CMSG_DATA(cmsg); |
| pi->ipi6_ifindex = ifindex; |
| } |
| |
| return sendmsg_loop(fd, &mh, 0); |
| } |
| |
| int manager_send(Manager *m, int fd, int ifindex, int family, const union in_addr_union *addr, uint16_t port, DnsPacket *p) { |
| assert(m); |
| assert(fd >= 0); |
| assert(addr); |
| assert(port > 0); |
| assert(p); |
| |
| log_debug("Sending %s packet with id %u on interface %i/%s", DNS_PACKET_QR(p) ? "response" : "query", DNS_PACKET_ID(p), ifindex, af_to_name(family)); |
| |
| if (family == AF_INET) |
| return manager_ipv4_send(m, fd, ifindex, &addr->in, port, p); |
| else if (family == AF_INET6) |
| return manager_ipv6_send(m, fd, ifindex, &addr->in6, port, p); |
| |
| return -EAFNOSUPPORT; |
| } |
| |
| DnsServer* manager_find_dns_server(Manager *m, int family, const union in_addr_union *in_addr) { |
| DnsServer *s; |
| |
| assert(m); |
| assert(in_addr); |
| |
| LIST_FOREACH(servers, s, m->dns_servers) |
| if (s->family == family && in_addr_equal(family, &s->address, in_addr) > 0) |
| return s; |
| |
| LIST_FOREACH(servers, s, m->fallback_dns_servers) |
| if (s->family == family && in_addr_equal(family, &s->address, in_addr) > 0) |
| return s; |
| |
| return NULL; |
| } |
| |
| DnsServer *manager_set_dns_server(Manager *m, DnsServer *s) { |
| assert(m); |
| |
| if (m->current_dns_server == s) |
| return s; |
| |
| if (s) { |
| _cleanup_free_ char *ip = NULL; |
| |
| in_addr_to_string(s->family, &s->address, &ip); |
| log_info("Switching to system DNS server %s.", strna(ip)); |
| } |
| |
| m->current_dns_server = s; |
| |
| if (m->unicast_scope) |
| dns_cache_flush(&m->unicast_scope->cache); |
| |
| return s; |
| } |
| |
| DnsServer *manager_get_dns_server(Manager *m) { |
| Link *l; |
| assert(m); |
| |
| /* Try to read updates resolv.conf */ |
| manager_read_resolv_conf(m); |
| |
| if (!m->current_dns_server) |
| manager_set_dns_server(m, m->dns_servers); |
| |
| if (!m->current_dns_server) { |
| bool found = false; |
| Iterator i; |
| |
| /* No DNS servers configured, let's see if there are |
| * any on any links. If not, we use the fallback |
| * servers */ |
| |
| HASHMAP_FOREACH(l, m->links, i) |
| if (l->dns_servers) { |
| found = true; |
| break; |
| } |
| |
| if (!found) |
| manager_set_dns_server(m, m->fallback_dns_servers); |
| } |
| |
| return m->current_dns_server; |
| } |
| |
| void manager_next_dns_server(Manager *m) { |
| assert(m); |
| |
| /* If there's currently no DNS server set, then the next |
| * manager_get_dns_server() will find one */ |
| if (!m->current_dns_server) |
| return; |
| |
| /* Change to the next one */ |
| if (m->current_dns_server->servers_next) { |
| manager_set_dns_server(m, m->current_dns_server->servers_next); |
| return; |
| } |
| |
| /* If there was no next one, then start from the beginning of |
| * the list */ |
| if (m->current_dns_server->type == DNS_SERVER_FALLBACK) |
| manager_set_dns_server(m, m->fallback_dns_servers); |
| else |
| manager_set_dns_server(m, m->dns_servers); |
| } |
| |
| uint32_t manager_find_mtu(Manager *m) { |
| uint32_t mtu = 0; |
| Link *l; |
| Iterator i; |
| |
| /* 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 */ |
| |
| HASHMAP_FOREACH(l, m->links, i) { |
| if (l->mtu <= 0) |
| continue; |
| |
| if (mtu <= 0 || l->mtu < mtu) |
| mtu = l->mtu; |
| } |
| |
| return mtu; |
| } |
| |
| int manager_find_ifindex(Manager *m, int family, const union in_addr_union *in_addr) { |
| LinkAddress *a; |
| |
| assert(m); |
| |
| a = manager_find_link_address(m, family, in_addr); |
| if (a) |
| return a->link->ifindex; |
| |
| return 0; |
| } |
| |
| void manager_refresh_rrs(Manager *m) { |
| Iterator i; |
| Link *l; |
| |
| 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); |
| |
| HASHMAP_FOREACH(l, m->links, i) { |
| link_add_rrs(l, true); |
| link_add_rrs(l, false); |
| } |
| } |
| |
| int manager_next_hostname(Manager *m) { |
| const char *p; |
| uint64_t u, a; |
| char *h, *k; |
| int r; |
| |
| assert(m); |
| |
| p = strchr(m->llmnr_hostname, 0); |
| assert(p); |
| |
| while (p > m->llmnr_hostname) { |
| if (!strchr("0123456789", 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(&h, "%.*s%" PRIu64, (int) (p - m->llmnr_hostname), m->llmnr_hostname, u) < 0) |
| return -ENOMEM; |
| |
| r = dns_name_concat(h, "local", &k); |
| if (r < 0) { |
| free(h); |
| return r; |
| } |
| |
| log_info("Hostname conflict, changing published hostname from '%s' to '%s'.", m->llmnr_hostname, h); |
| |
| free(m->llmnr_hostname); |
| m->llmnr_hostname = h; |
| |
| free(m->mdns_hostname); |
| m->mdns_hostname = k; |
| |
| manager_refresh_rrs(m); |
| |
| return 0; |
| } |
| |
| LinkAddress* manager_find_link_address(Manager *m, int family, const union in_addr_union *in_addr) { |
| Iterator i; |
| Link *l; |
| |
| assert(m); |
| |
| HASHMAP_FOREACH(l, m->links, i) { |
| LinkAddress *a; |
| |
| a = link_find_address(l, family, in_addr); |
| if (a) |
| return a; |
| } |
| |
| return NULL; |
| } |
| |
| bool manager_our_packet(Manager *m, DnsPacket *p) { |
| assert(m); |
| assert(p); |
| |
| return !!manager_find_link_address(m, p->family, &p->sender); |
| } |
| |
| 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; |
| |
| if (p->protocol == DNS_PROTOCOL_LLMNR) { |
| if (p->family == AF_INET) |
| return l->llmnr_ipv4_scope; |
| else if (p->family == AF_INET6) |
| return l->llmnr_ipv6_scope; |
| } |
| |
| 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); |
| } |
| |
| void manager_flush_dns_servers(Manager *m, DnsServerType t) { |
| DnsServer *s; |
| |
| assert(m); |
| |
| if (t == DNS_SERVER_SYSTEM) |
| while (m->dns_servers) { |
| s = m->dns_servers; |
| |
| LIST_REMOVE(servers, m->dns_servers, s); |
| dns_server_unref(s); |
| } |
| |
| if (t == DNS_SERVER_FALLBACK) |
| while (m->fallback_dns_servers) { |
| s = m->fallback_dns_servers; |
| |
| LIST_REMOVE(servers, m->fallback_dns_servers, s); |
| dns_server_unref(s); |
| } |
| } |
| |
| 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) |
| return dns_name_equal(name, m->mdns_hostname); |
| |
| return 0; |
| } |
| |
| static const char* const support_table[_SUPPORT_MAX] = { |
| [SUPPORT_NO] = "no", |
| [SUPPORT_YES] = "yes", |
| [SUPPORT_RESOLVE] = "resolve", |
| }; |
| DEFINE_STRING_TABLE_LOOKUP(support, Support); |