X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=blobdiff_plain;f=src%2Fresolve%2Fresolved-manager.c;h=00aaffe44899bdcf9efb01372ee03c2ac47ac603;hp=ae173991da2ca11cbb18102ea5fdd7650d3d690f;hb=d1c457badfce0dc86b54b2cac2c5eec99d7bc65e;hpb=091a364c802e34a58f3260c9cb5db9b75c62215c

diff --git a/src/resolve/resolved-manager.c b/src/resolve/resolved-manager.c
index ae173991d..00aaffe44 100644
--- a/src/resolve/resolved-manager.c
+++ b/src/resolve/resolved-manager.c
@@ -21,300 +21,1830 @@
 
 #include <arpa/inet.h>
 #include <resolv.h>
-#include <linux/if.h>
+#include <net/if.h>
+#include <sys/ioctl.h>
+#include <sys/poll.h>
+#include <netinet/in.h>
 
-#include "resolved.h"
+#include "rtnl-util.h"
 #include "event-util.h"
 #include "network-util.h"
-#include "sd-dhcp-lease.h"
-#include "dhcp-lease-internal.h"
 #include "network-internal.h"
 #include "conf-parser.h"
-#include "mkdir.h"
+#include "socket-util.h"
+#include "af-list.h"
+#include "utf8.h"
 
-static int set_fallback_dns(Manager *m, const char *string) {
-        char *word, *state;
-        size_t length;
-        int r;
+#include "resolved-dns-domain.h"
+#include "resolved-conf.h"
+#include "resolved-bus.h"
+#include "resolved-manager.h"
+
+#define SEND_TIMEOUT_USEC (200 * USEC_PER_MSEC)
+
+static int manager_process_link(sd_rtnl *rtnl, sd_rtnl_message *mm, void *userdata) {
+        Manager *m = userdata;
+        uint16_t type;
+        Link *l;
+        int ifindex, r;
 
+        assert(rtnl);
         assert(m);
-        assert(string);
+        assert(mm);
 
-        FOREACH_WORD_QUOTED(word, length, string, state) {
-                _cleanup_free_ Address *address = NULL;
-                Address *tail;
-                _cleanup_free_ char *addrstr = NULL;
+        r = sd_rtnl_message_get_type(mm, &type);
+        if (r < 0)
+                goto fail;
 
-                address = new0(Address, 1);
-                if (!address)
-                        return -ENOMEM;
+        r = sd_rtnl_message_link_get_ifindex(mm, &ifindex);
+        if (r < 0)
+                goto fail;
 
-                addrstr = strndup(word, length);
-                if (!addrstr)
-                        return -ENOMEM;
+        l = hashmap_get(m->links, INT_TO_PTR(ifindex));
 
-                r = net_parse_inaddr(addrstr, &address->family, &address->in_addr);
-                if (r < 0) {
-                        log_debug("Ignoring invalid DNS address '%s'", addrstr);
-                        continue;
+        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);
                 }
 
-                LIST_FIND_TAIL(addresses, m->fallback_dns, tail);
-                LIST_INSERT_AFTER(addresses, m->fallback_dns, tail, address);
-                address = NULL;
+                break;
         }
 
         return 0;
-}
 
-int config_parse_dnsv(
-                const char *unit,
-                const char *filename,
-                unsigned line,
-                const char *section,
-                unsigned section_line,
-                const char *lvalue,
-                int ltype,
-                const char *rvalue,
-                void *data,
-                void *userdata) {
+fail:
+        log_warning("Failed to process RTNL link message: %s", strerror(-r));
+        return 0;
+}
 
+static int manager_process_address(sd_rtnl *rtnl, sd_rtnl_message *mm, void *userdata) {
         Manager *m = userdata;
-        Address *address;
-
-        assert(filename);
-        assert(lvalue);
-        assert(rvalue);
+        union in_addr_union address;
+        uint16_t type;
+        int r, ifindex, family;
+        LinkAddress *a;
+        Link *l;
+
+        assert(rtnl);
+        assert(mm);
         assert(m);
 
-        while ((address = m->fallback_dns)) {
-                LIST_REMOVE(addresses, m->fallback_dns, address);
-                free(address);
+        r = sd_rtnl_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_rtnl_message_read_in_addr(mm, IFA_LOCAL, &address.in);
+                if (r < 0) {
+                        r = sd_rtnl_message_read_in_addr(mm, IFA_ADDRESS, &address.in);
+                        if (r < 0)
+                                goto fail;
+                }
+
+                break;
+
+        case AF_INET6:
+                r = sd_rtnl_message_read_in6_addr(mm, IFA_LOCAL, &address.in6);
+                if (r < 0) {
+                        r = sd_rtnl_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:
+                if (a)
+                        link_address_free(a);
+                break;
         }
 
-        set_fallback_dns(m, rvalue);
+        return 0;
 
+fail:
+        log_warning("Failed to process RTNL address message: %s", strerror(-r));
         return 0;
 }
 
-static int manager_parse_config_file(Manager *m) {
-        static const char fn[] = "/etc/systemd/resolved.conf";
-        _cleanup_fclose_ FILE *f = NULL;
+static int manager_rtnl_listen(Manager *m) {
+        _cleanup_rtnl_message_unref_ sd_rtnl_message *req = NULL, *reply = NULL;
+        sd_rtnl_message *i;
         int r;
 
         assert(m);
 
-        f = fopen(fn, "re");
-        if (!f) {
-                if (errno == ENOENT)
-                        return 0;
+        /* First, subscibe to interfaces coming and going */
+        r = sd_rtnl_open(&m->rtnl, 3, RTNLGRP_LINK, RTNLGRP_IPV4_IFADDR, RTNLGRP_IPV6_IFADDR);
+        if (r < 0)
+                return r;
 
-                log_warning("Failed to open configuration file %s: %m", fn);
-                return -errno;
-        }
+        r = sd_rtnl_attach_event(m->rtnl, m->event, 0);
+        if (r < 0)
+                return r;
 
-        r = config_parse(NULL, fn, f, "Resolve\0", config_item_perf_lookup,
-                         (void*) resolved_gperf_lookup, false, false, m);
+        r = sd_rtnl_add_match(m->rtnl, RTM_NEWLINK, manager_process_link, m);
         if (r < 0)
-                log_warning("Failed to parse configuration file: %s", strerror(-r));
+                return r;
 
-        return r;
-}
+        r = sd_rtnl_add_match(m->rtnl, RTM_DELLINK, manager_process_link, m);
+        if (r < 0)
+                return r;
 
-int manager_new(Manager **ret) {
-        _cleanup_manager_free_ Manager *m = NULL;
-        int r;
+        r = sd_rtnl_add_match(m->rtnl, RTM_NEWADDR, manager_process_address, m);
+        if (r < 0)
+                return r;
 
-        m = new0(Manager, 1);
-        if (!m)
-                return -ENOMEM;
+        r = sd_rtnl_add_match(m->rtnl, RTM_DELADDR, manager_process_address, m);
+        if (r < 0)
+                return r;
 
-        r = set_fallback_dns(m, DNS_SERVERS);
+        /* Then, enumerate all links */
+        r = sd_rtnl_message_new_link(m->rtnl, &req, RTM_GETLINK, 0);
         if (r < 0)
                 return r;
 
-        r = manager_parse_config_file(m);
+        r = sd_rtnl_message_request_dump(req, true);
         if (r < 0)
                 return r;
 
-        r = sd_event_default(&m->event);
+        r = sd_rtnl_call(m->rtnl, req, 0, &reply);
         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);
+        for (i = reply; i; i = sd_rtnl_message_next(i)) {
+                r = manager_process_link(m->rtnl, i, m);
+                if (r < 0)
+                        return r;
+        }
 
-        sd_event_set_watchdog(m->event, true);
+        req = sd_rtnl_message_unref(req);
+        reply = sd_rtnl_message_unref(reply);
 
-        *ret = m;
-        m = NULL;
+        /* Finally, enumerate all addresses, too */
+        r = sd_rtnl_message_new_addr(m->rtnl, &req, RTM_GETADDR, 0, AF_UNSPEC);
+        if (r < 0)
+                return r;
 
-        return 0;
+        r = sd_rtnl_message_request_dump(req, true);
+        if (r < 0)
+                return r;
+
+        r = sd_rtnl_call(m->rtnl, req, 0, &reply);
+        if (r < 0)
+                return r;
+
+        for (i = reply; i; i = sd_rtnl_message_next(i)) {
+                r = manager_process_address(m->rtnl, i, m);
+                if (r < 0)
+                        return r;
+        }
+
+        return r;
 }
 
-void manager_free(Manager *m) {
-        Address *address;
+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;
 
-        if (!m)
-                return;
+        assert(m);
 
-        sd_event_unref(m->event);
+        sd_network_monitor_flush(m->network_monitor);
 
-        while ((address = m->fallback_dns)) {
-                LIST_REMOVE(addresses, m->fallback_dns, address);
-                free(address);
+        HASHMAP_FOREACH(l, m->links, i) {
+                r = link_update_monitor(l);
+                if (r < 0)
+                        log_warning("Failed to update monitor information for %i: %s", l->ifindex, strerror(-r));
         }
 
-        free(m);
+        r = manager_write_resolv_conf(m);
+        if (r < 0)
+                log_warning("Could not update resolv.conf: %s", strerror(-r));
+
+        return 0;
 }
 
-static void append_dns(FILE *f, void *dns, unsigned char family, unsigned *count) {
-        char buf[INET6_ADDRSTRLEN];
-        const char *address;
+static int manager_network_monitor_listen(Manager *m) {
+        int r, fd, events;
 
-        assert(f);
-        assert(dns);
-        assert(count);
+        assert(m);
 
-        address = inet_ntop(family, dns, buf, INET6_ADDRSTRLEN);
-        if (!address) {
-                log_warning("Invalid DNS address. Ignoring.");
-                return;
+        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 **ret) {
+        _cleanup_free_ char *h = NULL, *n = NULL;
+        int r;
+
+        assert(ret);
+
+        h = gethostname_malloc();
+        if (!h)
+                return log_oom();
+
+        if (!utf8_is_valid(h)) {
+                log_error("System hostname is not UTF-8 clean.");
+                return -EINVAL;
         }
 
-        if (*count == MAXNS)
-                fputs("# Too many DNS servers configured, the following entries "
-                      "may be ignored\n", f);
+        r = dns_name_normalize(h, &n);
+        if (r < 0) {
+                log_error("System hostname '%s' cannot be normalized.", h);
+                return r;
+        }
 
-        fprintf(f, "nameserver %s\n", address);
+        *ret = n;
+        n = NULL;
 
-        (*count) ++;
+        return 0;
 }
 
-int manager_update_resolv_conf(Manager *m) {
-        _cleanup_free_ char *temp_path = NULL;
-        _cleanup_fclose_ FILE *f = NULL;
-         _cleanup_free_ unsigned *indices = NULL;
-        Address *address;
-        unsigned count = 0;
-        int n, r, i;
+static int on_hostname_change(sd_event_source *es, int fd, uint32_t revents, void *userdata) {
+        _cleanup_free_ char *h = NULL;
+        Manager *m = userdata;
+        int r;
 
         assert(m);
 
-        r = fopen_temporary("/run/systemd/network/resolv.conf", &f, &temp_path);
+        r = determine_hostname(&h);
         if (r < 0)
-                return r;
+                return 0; /* ignore invalid hostnames */
 
-        fchmod(fileno(f), 0644);
-
-        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 (streq(h, m->hostname))
+                return 0;
 
-        n = sd_network_get_ifindices(&indices);
-        if (n < 0)
-                n = 0;
-
-        for (i = 0; i < n; i++) {
-                _cleanup_dhcp_lease_unref_ sd_dhcp_lease *lease = NULL;
-                struct in_addr *nameservers;
-                struct in6_addr *nameservers6;
-                size_t nameservers_size;
-
-                r = sd_network_dhcp_use_dns(indices[i]);
-                if (r > 0) {
-                        r = sd_network_get_dhcp_lease(indices[i], &lease);
-                        if (r >= 0) {
-                                r = sd_dhcp_lease_get_dns(lease, &nameservers, &nameservers_size);
-                                if (r >= 0) {
-                                        unsigned j;
-
-                                        for (j = 0; j < nameservers_size; j++)
-                                                append_dns(f, &nameservers[j], AF_INET, &count);
-                                }
-                        }
-                }
+        log_info("System hostname changed to '%s'.", h);
+        free(m->hostname);
+        m->hostname = h;
+        h = NULL;
 
-                r = sd_network_get_dns(indices[i], &nameservers, &nameservers_size);
-                if (r >= 0) {
-                        unsigned j;
+        manager_refresh_rrs(m);
 
-                        for (j = 0; j < nameservers_size; j++)
-                                append_dns(f, &nameservers[j], AF_INET, &count);
+        return 0;
+}
 
-                        free(nameservers);
-                }
+static int manager_watch_hostname(Manager *m) {
+        int r;
 
-                r = sd_network_get_dns6(indices[i], &nameservers6, &nameservers_size);
-                if (r >= 0) {
-                        unsigned j;
+        assert(m);
 
-                        for (j = 0; j < nameservers_size; j++)
-                                append_dns(f, &nameservers6[j], AF_INET6, &count);
+        m->hostname_fd = open("/proc/sys/kernel/hostname", O_RDONLY|O_CLOEXEC|O_NDELAY|O_NOCTTY);
+        if (m->hostname_fd < 0) {
+                log_warning("Failed to watch hostname: %m");
+                return 0;
+        }
 
-                        free(nameservers6);
+        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 {
+                        log_error("Failed to add hostname event source: %s", strerror(-r));
+                        return r;
                 }
         }
 
-        LIST_FOREACH(addresses, address, m->fallback_dns)
-                append_dns(f, &address->in_addr, address->family, &count);
+        r = determine_hostname(&m->hostname);
+        if (r < 0) {
+                log_info("Defaulting to hostname 'linux'.");
+                m->hostname = strdup("linux");
+                if (!m->hostname)
+                        return log_oom();
+        } else
+                log_info("Using system hostname '%s'.", m->hostname);
+
+        return 0;
+}
 
-        fflush(f);
+static void manager_llmnr_stop(Manager *m) {
+        assert(m);
 
-        if (ferror(f) || rename(temp_path, "/run/systemd/network/resolv.conf") < 0) {
-                r = -errno;
-                unlink("/run/systemd/network/resolv.conf");
-                unlink(temp_path);
-                return r;
-        }
+        m->llmnr_ipv4_udp_event_source = sd_event_source_unref(m->llmnr_ipv4_udp_event_source);
+        m->llmnr_ipv4_udp_fd = safe_close(m->llmnr_ipv4_udp_fd);
 
-        return 0;
+        m->llmnr_ipv6_udp_event_source = sd_event_source_unref(m->llmnr_ipv6_udp_event_source);
+        m->llmnr_ipv6_udp_fd = safe_close(m->llmnr_ipv6_udp_fd);
+
+        m->llmnr_ipv4_tcp_event_source = sd_event_source_unref(m->llmnr_ipv4_tcp_event_source);
+        m->llmnr_ipv4_tcp_fd = safe_close(m->llmnr_ipv4_tcp_fd);
+
+        m->llmnr_ipv6_tcp_event_source = sd_event_source_unref(m->llmnr_ipv6_tcp_event_source);
+        m->llmnr_ipv6_tcp_fd = safe_close(m->llmnr_ipv6_tcp_fd);
 }
 
-static int manager_network_event_handler(sd_event_source *s, int fd, uint32_t revents,
-                                         void *userdata) {
-        Manager *m = userdata;
+static int manager_llmnr_start(Manager *m) {
         int r;
 
         assert(m);
 
-        r = manager_update_resolv_conf(m);
+        if (m->llmnr_support == SUPPORT_NO)
+                return 0;
+
+        r = manager_llmnr_ipv4_udp_fd(m);
+        if (r == -EADDRINUSE)
+                goto eaddrinuse;
         if (r < 0)
-                log_warning("Could not update resolv.conf: %s", strerror(-r));
+                return r;
 
-        sd_network_monitor_flush(m->network_monitor);
+        r = manager_llmnr_ipv4_tcp_fd(m);
+        if (r == -EADDRINUSE)
+                goto eaddrinuse;
+        if (r < 0)
+                return r;
+
+        if (socket_ipv6_is_supported()) {
+                r = manager_llmnr_ipv6_udp_fd(m);
+                if (r == -EADDRINUSE)
+                        goto eaddrinuse;
+                if (r < 0)
+                        return r;
+
+                r = manager_llmnr_ipv6_tcp_fd(m);
+                if (r == -EADDRINUSE)
+                        goto eaddrinuse;
+                if (r < 0)
+                        return r;
+        }
+
+        return 0;
+
+eaddrinuse:
+        log_warning("There appears to be another LLMNR responder running. Turning off LLMNR support.");
+        m->llmnr_support = SUPPORT_NO;
+        manager_llmnr_stop(m);
 
         return 0;
 }
 
-int manager_network_monitor_listen(Manager *m) {
-        _cleanup_event_source_unref_ sd_event_source *event_source = NULL;
-        _cleanup_network_monitor_unref_ sd_network_monitor *monitor = NULL;
-        int r, fd, events;
+int manager_new(Manager **ret) {
+        _cleanup_(manager_freep) Manager *m = NULL;
+        int r;
 
-        r = sd_network_monitor_new(NULL, &monitor);
+        assert(ret);
+
+        m = new0(Manager, 1);
+        if (!m)
+                return -ENOMEM;
+
+        m->dns_ipv4_fd = m->dns_ipv6_fd = -1;
+        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;
 
-        fd = sd_network_monitor_get_fd(monitor);
-        if (fd < 0)
-                return fd;
+        r = sd_event_default(&m->event);
+        if (r < 0)
+                return r;
 
-        events = sd_network_monitor_get_events(monitor);
-        if (events < 0)
-                return events;
+        sd_event_add_signal(m->event, NULL, SIGTERM, NULL,  NULL);
+        sd_event_add_signal(m->event, NULL, SIGINT, NULL, NULL);
 
-        r = sd_event_add_io(m->event, &event_source, fd, events,
-                            &manager_network_event_handler, m);
+        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;
 
-        m->network_monitor = monitor;
-        m->network_event_source = event_source;
-        monitor = NULL;
-        event_source = NULL;
+        r = manager_rtnl_listen(m);
+        if (r < 0)
+                return r;
+
+        r = manager_connect_bus(m);
+        if (r < 0)
+                return r;
+
+        *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);
+
+        dns_scope_free(m->unicast_scope);
+
+        manager_flush_dns_servers(m, DNS_SERVER_SYSTEM);
+        manager_flush_dns_servers(m, DNS_SERVER_FALLBACK);
+
+        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_event_source_unref(m->dns_ipv4_event_source);
+        sd_event_source_unref(m->dns_ipv6_event_source);
+        safe_close(m->dns_ipv4_fd);
+        safe_close(m->dns_ipv6_fd);
+
+        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_unref(m->event);
+
+        dns_resource_key_unref(m->host_ipv4_key);
+        dns_resource_key_unref(m->host_ipv6_key);
+
+        safe_close(m->hostname_fd);
+        sd_event_source_unref(m->hostname_event_source);
+        free(m->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("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("Failed to open /etc/resolv.conf: %m");
+                r = -errno;
+                goto clear;
+        }
+
+        if (fstat(fileno(f), &st) < 0) {
+                log_error("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)
+                        dns_server_free(s);
+
+        return 0;
+
+clear:
+        while (m->dns_servers)
+                dns_server_free(m->dns_servers);
+
+        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("Invalid DNS address. Ignoring: %s", strerror(-r));
+                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) ++;
+}
+
+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_set_free_ Set *dns = NULL, *domains = NULL;
+        unsigned count = 0;
+        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 = set_new(dns_server_hash_func, dns_server_compare_func);
+        if (!dns)
+                return -ENOMEM;
+
+        domains = set_new(dns_name_hash_func, dns_name_compare_func);
+        if (!domains)
+                return -ENOMEM;
+
+        /* First add the system-wide servers */
+        LIST_FOREACH(servers, s, m->dns_servers) {
+                r = 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 = 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 = set_put(domains, *domain);
+                        if (r == -EEXIST)
+                                continue;
+                        if (r < 0)
+                                return r;
+                }
+        }
+
+        /* If we found nothing, add the fallback servers */
+        if (set_isempty(dns)) {
+                LIST_FOREACH(servers, s, m->fallback_dns_servers) {
+                        r = set_put(dns, s);
+                        if (r == -EEXIST)
+                                continue;
+                        if (r < 0)
+                                return r;
+                }
+        }
+
+        r = fopen_temporary(path, &f, &temp_path);
+        if (r < 0)
+                return r;
+
+        fchmod(fileno(f), 0644);
+
+        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 (set_isempty(dns))
+                fputs("# No DNS servers known.\n", f);
+        else {
+                SET_FOREACH(s, dns, i)
+                        write_resolv_conf_server(s, f, &count);
+        }
+
+        if (!set_isempty(domains)) {
+                unsigned length = 0;
+                char *domain;
+
+                count = 0;
+
+                fputs("search", f);
+                SET_FOREACH(domain, domains, i)
+                        write_resolv_conf_search(domain, f, &count, &length);
+                fputs("\n", f);
+        }
+
+        r = fflush_and_check(f);
+        if (r < 0)
+                goto fail;
+
+        if (rename(temp_path, path) < 0) {
+                r = -errno;
+                goto fail;
+        }
+
+        return 0;
+
+fail:
+        unlink(path);
+        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;
+
+        for (cmsg = CMSG_FIRSTHDR(&mh); cmsg; cmsg = CMSG_NXTHDR(&mh, cmsg)) {
+
+                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 > 0 && manager_ifindex_is_loopback(m, p->ifindex) != 0)
+                p->ifindex = 0;
+
+        /* 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 on_dns_packet(sd_event_source *s, int fd, uint32_t revents, void *userdata) {
+        _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL;
+        DnsTransaction *t = NULL;
+        Manager *m = userdata;
+        int r;
+
+        r = manager_recv(m, fd, DNS_PROTOCOL_DNS, &p);
+        if (r <= 0)
+                return r;
+
+        if (dns_packet_validate_reply(p) > 0) {
+                t = hashmap_get(m->dns_transactions, UINT_TO_PTR(DNS_PACKET_ID(p)));
+                if (!t)
+                        return 0;
+
+                dns_transaction_process_reply(t, p);
+
+        } else
+                log_debug("Invalid DNS packet.");
+
+        return 0;
+}
+
+int manager_dns_ipv4_fd(Manager *m) {
+        const int one = 1;
+        int r;
+
+        assert(m);
+
+        if (m->dns_ipv4_fd >= 0)
+                return m->dns_ipv4_fd;
+
+        m->dns_ipv4_fd = socket(AF_INET, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
+        if (m->dns_ipv4_fd < 0)
+                return -errno;
+
+        r = setsockopt(m->dns_ipv4_fd, IPPROTO_IP, IP_PKTINFO, &one, sizeof(one));
+        if (r < 0) {
+                r = -errno;
+                goto fail;
+        }
+
+        r = sd_event_add_io(m->event, &m->dns_ipv4_event_source, m->dns_ipv4_fd, EPOLLIN, on_dns_packet, m);
+        if (r < 0)
+                goto fail;
+
+        return m->dns_ipv4_fd;
+
+fail:
+        m->dns_ipv4_fd = safe_close(m->dns_ipv4_fd);
+        return r;
+}
+
+int manager_dns_ipv6_fd(Manager *m) {
+        const int one = 1;
+        int r;
+
+        assert(m);
+
+        if (m->dns_ipv6_fd >= 0)
+                return m->dns_ipv6_fd;
+
+        m->dns_ipv6_fd = socket(AF_INET6, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
+        if (m->dns_ipv6_fd < 0)
+                return -errno;
+
+        r = setsockopt(m->dns_ipv6_fd, IPPROTO_IPV6, IPV6_RECVPKTINFO, &one, sizeof(one));
+        if (r < 0) {
+                r = -errno;
+                goto fail;
+        }
+
+        r = sd_event_add_io(m->event, &m->dns_ipv6_event_source, m->dns_ipv6_fd, EPOLLIN, on_dns_packet, m);
+        if (r < 0)
+                goto fail;
+
+        return m->dns_ipv6_fd;
+
+fail:
+        m->dns_ipv6_fd = safe_close(m->dns_ipv6_fd);
+        return r;
+}
+
+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 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;
+}
+
+static int on_llmnr_packet(sd_event_source *s, int fd, uint32_t revents, void *userdata) {
+        _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL;
+        DnsTransaction *t = NULL;
+        Manager *m = userdata;
+        DnsScope *scope;
+        int r;
+
+        r = manager_recv(m, fd, DNS_PROTOCOL_LLMNR, &p);
+        if (r <= 0)
+                return r;
+
+        scope = manager_find_scope(m, p);
+        if (!scope) {
+                log_warning("Got LLMNR UDP packet on unknown scope. Ignoring.");
+                return 0;
+        }
+
+        if (dns_packet_validate_reply(p) > 0) {
+                log_debug("Got reply packet for id %u", DNS_PACKET_ID(p));
+
+                dns_scope_check_conflicts(scope, p);
+
+                t = hashmap_get(m->dns_transactions, UINT_TO_PTR(DNS_PACKET_ID(p)));
+                if (t)
+                        dns_transaction_process_reply(t, p);
+
+        } else if (dns_packet_validate_query(p) > 0)  {
+                log_debug("Got query packet for id %u", DNS_PACKET_ID(p));
+
+                dns_scope_process_query(scope, NULL, p);
+        } else
+                log_debug("Invalid LLMNR UDP packet.");
+
+        return 0;
+}
+
+int manager_llmnr_ipv4_udp_fd(Manager *m) {
+        union sockaddr_union sa = {
+                .in.sin_family = AF_INET,
+                .in.sin_port = htobe16(5355),
+        };
+        static const int one = 1, pmtu = IP_PMTUDISC_DONT, ttl = 255;
+        int r;
+
+        assert(m);
+
+        if (m->llmnr_ipv4_udp_fd >= 0)
+                return m->llmnr_ipv4_udp_fd;
+
+        m->llmnr_ipv4_udp_fd = socket(AF_INET, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
+        if (m->llmnr_ipv4_udp_fd < 0)
+                return -errno;
+
+        /* RFC 4795, section 2.5 recommends setting the TTL of UDP packets to 255. */
+        r = setsockopt(m->llmnr_ipv4_udp_fd, IPPROTO_IP, IP_TTL, &ttl, sizeof(ttl));
+        if (r < 0) {
+                r = -errno;
+                goto fail;
+        }
+
+        r = setsockopt(m->llmnr_ipv4_udp_fd, IPPROTO_IP, IP_MULTICAST_TTL, &ttl, sizeof(ttl));
+        if (r < 0) {
+                r = -errno;
+                goto fail;
+        }
+
+        r = setsockopt(m->llmnr_ipv4_udp_fd, IPPROTO_IP, IP_MULTICAST_LOOP, &one, sizeof(one));
+        if (r < 0) {
+                r = -errno;
+                goto fail;
+        }
+
+        r = setsockopt(m->llmnr_ipv4_udp_fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
+        if (r < 0) {
+                r = -errno;
+                goto fail;
+        }
+
+        r = setsockopt(m->llmnr_ipv4_udp_fd, IPPROTO_IP, IP_PKTINFO, &one, sizeof(one));
+        if (r < 0) {
+                r = -errno;
+                goto fail;
+        }
+
+        r = setsockopt(m->llmnr_ipv4_udp_fd, IPPROTO_IP, IP_RECVTTL, &one, sizeof(one));
+        if (r < 0) {
+                r = -errno;
+                goto fail;
+        }
+
+        /* Disable Don't-Fragment bit in the IP header */
+        r = setsockopt(m->llmnr_ipv4_udp_fd, IPPROTO_IP, IP_MTU_DISCOVER, &pmtu, sizeof(pmtu));
+        if (r < 0) {
+                r = -errno;
+                goto fail;
+        }
+
+        r = bind(m->llmnr_ipv4_udp_fd, &sa.sa, sizeof(sa.in));
+        if (r < 0) {
+                r = -errno;
+                goto fail;
+        }
+
+        r = sd_event_add_io(m->event, &m->llmnr_ipv4_udp_event_source, m->llmnr_ipv4_udp_fd, EPOLLIN, on_llmnr_packet, m);
+        if (r < 0)
+                goto fail;
+
+        return m->llmnr_ipv4_udp_fd;
+
+fail:
+        m->llmnr_ipv4_udp_fd = safe_close(m->llmnr_ipv4_udp_fd);
+        return r;
+}
+
+int manager_llmnr_ipv6_udp_fd(Manager *m) {
+        union sockaddr_union sa = {
+                .in6.sin6_family = AF_INET6,
+                .in6.sin6_port = htobe16(5355),
+        };
+        static const int one = 1, ttl = 255;
+        int r;
+
+        assert(m);
+
+        if (m->llmnr_ipv6_udp_fd >= 0)
+                return m->llmnr_ipv6_udp_fd;
+
+        m->llmnr_ipv6_udp_fd = socket(AF_INET6, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
+        if (m->llmnr_ipv6_udp_fd < 0)
+                return -errno;
+
+        r = setsockopt(m->llmnr_ipv6_udp_fd, IPPROTO_IPV6, IPV6_UNICAST_HOPS, &ttl, sizeof(ttl));
+        if (r < 0) {
+                r = -errno;
+                goto fail;
+        }
+
+        /* RFC 4795, section 2.5 recommends setting the TTL of UDP packets to 255. */
+        r = setsockopt(m->llmnr_ipv6_udp_fd, IPPROTO_IPV6, IPV6_MULTICAST_HOPS, &ttl, sizeof(ttl));
+        if (r < 0) {
+                r = -errno;
+                goto fail;
+        }
+
+        r = setsockopt(m->llmnr_ipv6_udp_fd, IPPROTO_IPV6, IPV6_MULTICAST_LOOP, &one, sizeof(one));
+        if (r < 0) {
+                r = -errno;
+                goto fail;
+        }
+
+        r = setsockopt(m->llmnr_ipv6_udp_fd, IPPROTO_IPV6, IPV6_V6ONLY, &one, sizeof(one));
+        if (r < 0) {
+                r = -errno;
+                goto fail;
+        }
+
+        r = setsockopt(m->llmnr_ipv6_udp_fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
+        if (r < 0) {
+                r = -errno;
+                goto fail;
+        }
+
+        r = setsockopt(m->llmnr_ipv6_udp_fd, IPPROTO_IPV6, IPV6_RECVPKTINFO, &one, sizeof(one));
+        if (r < 0) {
+                r = -errno;
+                goto fail;
+        }
+
+        r = setsockopt(m->llmnr_ipv6_udp_fd, IPPROTO_IPV6, IPV6_RECVHOPLIMIT, &one, sizeof(one));
+        if (r < 0) {
+                r = -errno;
+                goto fail;
+        }
+
+        r = bind(m->llmnr_ipv6_udp_fd, &sa.sa, sizeof(sa.in6));
+        if (r < 0) {
+                r = -errno;
+                goto fail;
+        }
+
+        r = sd_event_add_io(m->event, &m->llmnr_ipv6_udp_event_source, m->llmnr_ipv6_udp_fd, EPOLLIN, on_llmnr_packet, m);
+        if (r < 0)  {
+                r = -errno;
+                goto fail;
+        }
+
+        return m->llmnr_ipv6_udp_fd;
+
+fail:
+        m->llmnr_ipv6_udp_fd = safe_close(m->llmnr_ipv6_udp_fd);
+        return r;
+}
+
+static int on_llmnr_stream_packet(DnsStream *s) {
+        DnsScope *scope;
+
+        assert(s);
+
+        scope = manager_find_scope(s->manager, s->read_packet);
+        if (!scope) {
+                log_warning("Got LLMNR TCP packet on unknown scope. Ignroing.");
+                return 0;
+        }
+
+        if (dns_packet_validate_query(s->read_packet) > 0) {
+                log_debug("Got query packet for id %u", DNS_PACKET_ID(s->read_packet));
+
+                dns_scope_process_query(scope, s, s->read_packet);
+
+                /* If no reply packet was set, we free the stream */
+                if (s->write_packet)
+                        return 0;
+        } else
+                log_debug("Invalid LLMNR TCP packet.");
+
+        dns_stream_free(s);
+        return 0;
+}
+
+static int on_llmnr_stream(sd_event_source *s, int fd, uint32_t revents, void *userdata) {
+        DnsStream *stream;
+        Manager *m = userdata;
+        int cfd, r;
+
+        cfd = accept4(fd, NULL, NULL, SOCK_NONBLOCK|SOCK_CLOEXEC);
+        if (cfd < 0) {
+                if (errno == EAGAIN || errno == EINTR)
+                        return 0;
+
+                return -errno;
+        }
+
+        r = dns_stream_new(m, &stream, DNS_PROTOCOL_LLMNR, cfd);
+        if (r < 0) {
+                safe_close(cfd);
+                return r;
+        }
+
+        stream->on_packet = on_llmnr_stream_packet;
+        return 0;
+}
+
+int manager_llmnr_ipv4_tcp_fd(Manager *m) {
+        union sockaddr_union sa = {
+                .in.sin_family = AF_INET,
+                .in.sin_port = htobe16(5355),
+        };
+        static const int one = 1, pmtu = IP_PMTUDISC_DONT;
+        int r;
+
+        assert(m);
+
+        if (m->llmnr_ipv4_tcp_fd >= 0)
+                return m->llmnr_ipv4_tcp_fd;
+
+        m->llmnr_ipv4_tcp_fd = socket(AF_INET, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
+        if (m->llmnr_ipv4_tcp_fd < 0)
+                return -errno;
+
+        /* RFC 4795, section 2.5. requires setting the TTL of TCP streams to 1 */
+        r = setsockopt(m->llmnr_ipv4_tcp_fd, IPPROTO_IP, IP_TTL, &one, sizeof(one));
+        if (r < 0) {
+                r = -errno;
+                goto fail;
+        }
+
+        r = setsockopt(m->llmnr_ipv4_tcp_fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
+        if (r < 0) {
+                r = -errno;
+                goto fail;
+        }
+
+        r = setsockopt(m->llmnr_ipv4_tcp_fd, IPPROTO_IP, IP_PKTINFO, &one, sizeof(one));
+        if (r < 0) {
+                r = -errno;
+                goto fail;
+        }
+
+        r = setsockopt(m->llmnr_ipv4_tcp_fd, IPPROTO_IP, IP_RECVTTL, &one, sizeof(one));
+        if (r < 0) {
+                r = -errno;
+                goto fail;
+        }
+
+        /* Disable Don't-Fragment bit in the IP header */
+        r = setsockopt(m->llmnr_ipv4_tcp_fd, IPPROTO_IP, IP_MTU_DISCOVER, &pmtu, sizeof(pmtu));
+        if (r < 0) {
+                r = -errno;
+                goto fail;
+        }
+
+        r = bind(m->llmnr_ipv4_tcp_fd, &sa.sa, sizeof(sa.in));
+        if (r < 0) {
+                r = -errno;
+                goto fail;
+        }
+
+        r = listen(m->llmnr_ipv4_tcp_fd, SOMAXCONN);
+        if (r < 0) {
+                r = -errno;
+                goto fail;
+        }
+
+        r = sd_event_add_io(m->event, &m->llmnr_ipv4_tcp_event_source, m->llmnr_ipv4_tcp_fd, EPOLLIN, on_llmnr_stream, m);
+        if (r < 0)
+                goto fail;
+
+        return m->llmnr_ipv4_tcp_fd;
+
+fail:
+        m->llmnr_ipv4_tcp_fd = safe_close(m->llmnr_ipv4_tcp_fd);
+        return r;
+}
+
+int manager_llmnr_ipv6_tcp_fd(Manager *m) {
+        union sockaddr_union sa = {
+                .in6.sin6_family = AF_INET6,
+                .in6.sin6_port = htobe16(5355),
+        };
+        static const int one = 1;
+        int r;
+
+        assert(m);
+
+        if (m->llmnr_ipv6_tcp_fd >= 0)
+                return m->llmnr_ipv6_tcp_fd;
+
+        m->llmnr_ipv6_tcp_fd = socket(AF_INET6, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
+        if (m->llmnr_ipv6_tcp_fd < 0)
+                return -errno;
+
+        /* RFC 4795, section 2.5. requires setting the TTL of TCP streams to 1 */
+        r = setsockopt(m->llmnr_ipv6_tcp_fd, IPPROTO_IPV6, IPV6_UNICAST_HOPS, &one, sizeof(one));
+        if (r < 0) {
+                r = -errno;
+                goto fail;
+        }
+
+        r = setsockopt(m->llmnr_ipv6_tcp_fd, IPPROTO_IPV6, IPV6_V6ONLY, &one, sizeof(one));
+        if (r < 0) {
+                r = -errno;
+                goto fail;
+        }
+
+        r = setsockopt(m->llmnr_ipv6_tcp_fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
+        if (r < 0) {
+                r = -errno;
+                goto fail;
+        }
+
+        r = setsockopt(m->llmnr_ipv6_tcp_fd, IPPROTO_IPV6, IPV6_RECVPKTINFO, &one, sizeof(one));
+        if (r < 0) {
+                r = -errno;
+                goto fail;
+        }
+
+        r = setsockopt(m->llmnr_ipv6_tcp_fd, IPPROTO_IPV6, IPV6_RECVHOPLIMIT, &one, sizeof(one));
+        if (r < 0) {
+                r = -errno;
+                goto fail;
+        }
+
+        r = bind(m->llmnr_ipv6_tcp_fd, &sa.sa, sizeof(sa.in6));
+        if (r < 0) {
+                r = -errno;
+                goto fail;
+        }
+
+        r = listen(m->llmnr_ipv6_tcp_fd, SOMAXCONN);
+        if (r < 0) {
+                r = -errno;
+                goto fail;
+        }
+
+        r = sd_event_add_io(m->event, &m->llmnr_ipv6_tcp_event_source, m->llmnr_ipv6_tcp_fd, EPOLLIN, on_llmnr_stream, m);
+        if (r < 0)  {
+                r = -errno;
+                goto fail;
+        }
+
+        return m->llmnr_ipv6_tcp_fd;
+
+fail:
+        m->llmnr_ipv6_tcp_fd = safe_close(m->llmnr_ipv6_tcp_fd);
+        return r;
+}
+
+/* lo having ifindex 1 is hardcoded in the kernel */
+#define LOOPBACK_IFINDEX 1
+
+int manager_ifindex_is_loopback(Manager *m, int ifindex) {
+        Link *l;
+        assert(m);
+
+        if (ifindex <= 0)
+                return -EINVAL;
+
+        l = hashmap_get(m->links, INT_TO_PTR(ifindex));
+        if (!l)
+                /* in case we don't yet track the link, rely on the hardcoded value */
+                return ifindex == LOOPBACK_IFINDEX;
+        else if (l->flags & IFF_LOOPBACK)
+                return 1;
+
+        return 0;
+}
+
+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->host_ipv4_key = dns_resource_key_unref(m->host_ipv4_key);
+        m->host_ipv6_key = dns_resource_key_unref(m->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;
+
+        assert(m);
+
+        p = strchr(m->hostname, 0);
+        assert(p);
+
+        while (p > m->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->hostname), m->hostname, u) < 0)
+                return -ENOMEM;
+
+        log_info("Hostname conflict, changing published hostname from '%s' to '%s'.", m->hostname, h);
+
+        free(m->hostname);
+        m->hostname = h;
+
+        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) {
+        assert(m);
+
+        if (t == DNS_SERVER_SYSTEM)
+                while (m->dns_servers)
+                        dns_server_free(m->dns_servers);
+
+        if (t == DNS_SERVER_FALLBACK)
+                while (m->fallback_dns_servers)
+                        dns_server_free(m->fallback_dns_servers);
+}
+
+static const char* const support_table[_SUPPORT_MAX] = {
+        [SUPPORT_NO] = "no",
+        [SUPPORT_YES] = "yes",
+        [SUPPORT_RESOLVE] = "resolve",
+};
+DEFINE_STRING_TABLE_LOOKUP(support, Support);