]> git.ipfire.org Git - thirdparty/systemd.git/blobdiff - src/resolve/resolved-manager.c
Bug #944: Deletion of unnecessary checks before calls of the function "free"
[thirdparty/systemd.git] / src / resolve / resolved-manager.c
index a2de2edb48f5a76d2398dc3abbd2ca03bcea352a..5be01d3cb8a7ae079d56e3ad59476e0099d579e0 100644 (file)
   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  ***/
 
-#include <arpa/inet.h>
 #include <resolv.h>
-#include <net/if.h>
 #include <sys/ioctl.h>
-#include <sys/poll.h>
+#include <poll.h>
 #include <netinet/in.h>
 
-#include "rtnl-util.h"
-#include "event-util.h"
-#include "network-util.h"
+#include "netlink-util.h"
 #include "network-internal.h"
-#include "conf-parser.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 "resolved-dns-domain.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_rtnl *rtnl, sd_rtnl_message *mm, void *userdata) {
+static int manager_process_link(sd_netlink *rtnl, sd_netlink_message *mm, void *userdata) {
         Manager *m = userdata;
         uint16_t type;
         Link *l;
@@ -52,7 +52,7 @@ static int manager_process_link(sd_rtnl *rtnl, sd_rtnl_message *mm, void *userda
         assert(m);
         assert(mm);
 
-        r = sd_rtnl_message_get_type(mm, &type);
+        r = sd_netlink_message_get_type(mm, &type);
         if (r < 0)
                 goto fail;
 
@@ -99,11 +99,11 @@ static int manager_process_link(sd_rtnl *rtnl, sd_rtnl_message *mm, void *userda
         return 0;
 
 fail:
-        log_warning("Failed to process RTNL link message: %s", strerror(-r));
+        log_warning_errno(r, "Failed to process RTNL link message: %m");
         return 0;
 }
 
-static int manager_process_address(sd_rtnl *rtnl, sd_rtnl_message *mm, void *userdata) {
+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;
@@ -115,7 +115,7 @@ static int manager_process_address(sd_rtnl *rtnl, sd_rtnl_message *mm, void *use
         assert(mm);
         assert(m);
 
-        r = sd_rtnl_message_get_type(mm, &type);
+        r = sd_netlink_message_get_type(mm, &type);
         if (r < 0)
                 goto fail;
 
@@ -134,9 +134,9 @@ static int manager_process_address(sd_rtnl *rtnl, sd_rtnl_message *mm, void *use
         switch (family) {
 
         case AF_INET:
-                r = sd_rtnl_message_read_in_addr(mm, IFA_LOCAL, &address.in);
+                r = sd_netlink_message_read_in_addr(mm, IFA_LOCAL, &address.in);
                 if (r < 0) {
-                        r = sd_rtnl_message_read_in_addr(mm, IFA_ADDRESS, &address.in);
+                        r = sd_netlink_message_read_in_addr(mm, IFA_ADDRESS, &address.in);
                         if (r < 0)
                                 goto fail;
                 }
@@ -144,9 +144,9 @@ static int manager_process_address(sd_rtnl *rtnl, sd_rtnl_message *mm, void *use
                 break;
 
         case AF_INET6:
-                r = sd_rtnl_message_read_in6_addr(mm, IFA_LOCAL, &address.in6);
+                r = sd_netlink_message_read_in6_addr(mm, IFA_LOCAL, &address.in6);
                 if (r < 0) {
-                        r = sd_rtnl_message_read_in6_addr(mm, IFA_ADDRESS, &address.in6);
+                        r = sd_netlink_message_read_in6_addr(mm, IFA_ADDRESS, &address.in6);
                         if (r < 0)
                                 goto fail;
                 }
@@ -184,39 +184,39 @@ static int manager_process_address(sd_rtnl *rtnl, sd_rtnl_message *mm, void *use
         return 0;
 
 fail:
-        log_warning("Failed to process RTNL address message: %s", strerror(-r));
+        log_warning_errno(r, "Failed to process RTNL address message: %m");
         return 0;
 }
 
 static int manager_rtnl_listen(Manager *m) {
-        _cleanup_rtnl_message_unref_ sd_rtnl_message *req = NULL, *reply = NULL;
-        sd_rtnl_message *i;
+        _cleanup_netlink_message_unref_ sd_netlink_message *req = NULL, *reply = NULL;
+        sd_netlink_message *i;
         int r;
 
         assert(m);
 
-        /* First, subscibe to interfaces coming and going */
-        r = sd_rtnl_open(&m->rtnl, 3, RTNLGRP_LINK, RTNLGRP_IPV4_IFADDR, RTNLGRP_IPV6_IFADDR);
+        /* First, subscribe to interfaces coming and going */
+        r = sd_netlink_open(&m->rtnl);
         if (r < 0)
                 return r;
 
-        r = sd_rtnl_attach_event(m->rtnl, m->event, 0);
+        r = sd_netlink_attach_event(m->rtnl, m->event, 0);
         if (r < 0)
                 return r;
 
-        r = sd_rtnl_add_match(m->rtnl, RTM_NEWLINK, manager_process_link, m);
+        r = sd_netlink_add_match(m->rtnl, RTM_NEWLINK, manager_process_link, m);
         if (r < 0)
                 return r;
 
-        r = sd_rtnl_add_match(m->rtnl, RTM_DELLINK, manager_process_link, m);
+        r = sd_netlink_add_match(m->rtnl, RTM_DELLINK, manager_process_link, m);
         if (r < 0)
                 return r;
 
-        r = sd_rtnl_add_match(m->rtnl, RTM_NEWADDR, manager_process_address, m);
+        r = sd_netlink_add_match(m->rtnl, RTM_NEWADDR, manager_process_address, m);
         if (r < 0)
                 return r;
 
-        r = sd_rtnl_add_match(m->rtnl, RTM_DELADDR, manager_process_address, m);
+        r = sd_netlink_add_match(m->rtnl, RTM_DELADDR, manager_process_address, m);
         if (r < 0)
                 return r;
 
@@ -225,37 +225,37 @@ static int manager_rtnl_listen(Manager *m) {
         if (r < 0)
                 return r;
 
-        r = sd_rtnl_message_request_dump(req, true);
+        r = sd_netlink_message_request_dump(req, true);
         if (r < 0)
                 return r;
 
-        r = sd_rtnl_call(m->rtnl, req, 0, &reply);
+        r = sd_netlink_call(m->rtnl, req, 0, &reply);
         if (r < 0)
                 return r;
 
-        for (i = reply; i; i = sd_rtnl_message_next(i)) {
+        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_rtnl_message_unref(req);
-        reply = sd_rtnl_message_unref(reply);
+        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_rtnl_message_request_dump(req, true);
+        r = sd_netlink_message_request_dump(req, true);
         if (r < 0)
                 return r;
 
-        r = sd_rtnl_call(m->rtnl, req, 0, &reply);
+        r = sd_netlink_call(m->rtnl, req, 0, &reply);
         if (r < 0)
                 return r;
 
-        for (i = reply; i; i = sd_rtnl_message_next(i)) {
+        for (i = reply; i; i = sd_netlink_message_next(i)) {
                 r = manager_process_address(m->rtnl, i, m);
                 if (r < 0)
                         return r;
@@ -277,12 +277,12 @@ static int on_network_event(sd_event_source *s, int fd, uint32_t revents, void *
         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));
+                        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("Could not update resolv.conf: %s", strerror(-r));
+                log_warning_errno(r, "Could not update resolv.conf: %m");
 
         return 0;
 }
@@ -369,7 +369,7 @@ static int manager_watch_hostname(Manager *m) {
 
         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");
+                log_warning_errno(errno, "Failed to watch hostname: %m");
                 return 0;
         }
 
@@ -378,10 +378,8 @@ static int manager_watch_hostname(Manager *m) {
                 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;
-                }
+                else
+                        return log_error_errno(r, "Failed to add hostname event source: %m");
         }
 
         r = determine_hostname(&m->hostname);
@@ -396,63 +394,6 @@ static int manager_watch_hostname(Manager *m) {
         return 0;
 }
 
-static void manager_llmnr_stop(Manager *m) {
-        assert(m);
-
-        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);
-
-        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_llmnr_start(Manager *m) {
-        int r;
-
-        assert(m);
-
-        if (m->llmnr_support == SUPPORT_NO)
-                return 0;
-
-        r = manager_llmnr_ipv4_udp_fd(m);
-        if (r == -EADDRINUSE)
-                goto eaddrinuse;
-        if (r < 0)
-                return r;
-
-        r = manager_llmnr_ipv6_udp_fd(m);
-        if (r == -EADDRINUSE)
-                goto eaddrinuse;
-        if (r < 0)
-                return r;
-
-        r = manager_llmnr_ipv4_tcp_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 respondering running. Turning off LLMNR support.");
-        m->llmnr_support = SUPPORT_NO;
-        manager_llmnr_stop(m);
-        return 0;
-}
-
 int manager_new(Manager **ret) {
         _cleanup_(manager_freep) Manager *m = NULL;
         int r;
@@ -463,7 +404,6 @@ int manager_new(Manager **ret) {
         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;
@@ -534,22 +474,17 @@ Manager *manager_free(Manager *m) {
         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);
 
+        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);
 
-        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);
@@ -589,7 +524,7 @@ int manager_read_resolv_conf(Manager *m) {
         r = stat("/etc/resolv.conf", &st);
         if (r < 0) {
                 if (errno != ENOENT)
-                        log_warning("Failed to open /etc/resolv.conf: %m");
+                        log_warning_errno(errno, "Failed to open /etc/resolv.conf: %m");
                 r = -errno;
                 goto clear;
         }
@@ -612,13 +547,13 @@ int manager_read_resolv_conf(Manager *m) {
         f = fopen("/etc/resolv.conf", "re");
         if (!f) {
                 if (errno != ENOENT)
-                        log_warning("Failed to open /etc/resolv.conf: %m");
+                        log_warning_errno(errno, "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");
+                log_error_errno(errno, "Failed to stat open file: %m");
                 r = -errno;
                 goto clear;
         }
@@ -662,19 +597,35 @@ int manager_read_resolv_conf(Manager *m) {
         }
 
         LIST_FOREACH_SAFE(servers, s, nx, m->dns_servers)
-                if (s->marked)
-                        dns_server_free(s);
+                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)
-                dns_server_free(m->dns_servers);
+        while (m->dns_servers) {
+                s = m->dns_servers;
+
+                LIST_REMOVE(servers, m->dns_servers, s);
+                dns_server_unref(s);
+        }
 
         return r;
 }
 
-static void write_resolve_conf_server(DnsServer *s, FILE *f, unsigned *count) {
+static void write_resolv_conf_server(DnsServer *s, FILE *f, unsigned *count) {
         _cleanup_free_ char *t  = NULL;
         int r;
 
@@ -684,7 +635,7 @@ static void write_resolve_conf_server(DnsServer *s, FILE *f, unsigned *count) {
 
         r = in_addr_to_string(s->family, &s->address, &t);
         if (r < 0) {
-                log_warning("Invalid DNS address. Ignoring: %s", strerror(-r));
+                log_warning_errno(r, "Invalid DNS address. Ignoring: %m");
                 return;
         }
 
@@ -695,12 +646,68 @@ static void write_resolve_conf_server(DnsServer *s, FILE *f, unsigned *count) {
         (*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_set_free_ Set *dns = NULL;
-        unsigned count = 0;
+        _cleanup_ordered_set_free_ OrderedSet *dns = NULL, *domains = NULL;
         DnsServer *s;
         Iterator i;
         Link *l;
@@ -712,33 +719,51 @@ int manager_write_resolv_conf(Manager *m) {
         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);
+        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 = set_put(dns, s);
+                r = ordered_set_put(dns, s);
                 if (r == -EEXIST)
                         continue;
                 if (r < 0)
                         return r;
         }
 
-        /* Then, add the per-link servers */
-        HASHMAP_FOREACH(l, m->links, i)
+        /* 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);
+                        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 (set_isempty(dns)) {
+        if (ordered_set_isempty(dns)) {
                 LIST_FOREACH(servers, s, m->fallback_dns_servers) {
-                        r = set_put(dns, s);
+                        r = ordered_set_put(dns, s);
                         if (r == -EEXIST)
                                 continue;
                         if (r < 0)
@@ -746,26 +771,13 @@ int manager_write_resolv_conf(Manager *m) {
                 }
         }
 
-        r = fopen_temporary(path, &f, &temp_path);
+        r = fopen_temporary_label(path, 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_resolve_conf_server(s, f, &count);
-        }
-
-        r = fflush_and_check(f);
+        r = write_resolv_conf_contents(f, dns, domains);
         if (r < 0)
                 goto fail;
 
@@ -777,8 +789,8 @@ int manager_write_resolv_conf(Manager *m) {
         return 0;
 
 fail:
-        unlink(path);
-        unlink(temp_path);
+        (void) unlink(path);
+        (void) unlink(temp_path);
         return r;
 }
 
@@ -786,7 +798,7 @@ 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(MAX(sizeof(struct in_pktinfo), sizeof(struct in6_pktinfo)))
+                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;
@@ -849,7 +861,7 @@ int manager_recv(Manager *m, int fd, DnsProtocol protocol, DnsPacket **ret) {
         } else
                 return -EAFNOSUPPORT;
 
-        for (cmsg = CMSG_FIRSTHDR(&mh); cmsg; cmsg = CMSG_NXTHDR(&mh, cmsg)) {
+        CMSG_FOREACH(cmsg, &mh) {
 
                 if (cmsg->cmsg_level == IPPROTO_IPV6) {
                         assert(p->family == AF_INET6);
@@ -897,13 +909,15 @@ int manager_recv(Manager *m, int fd, DnsProtocol protocol, DnsPacket **ret) {
          * 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)
+        if (p->ifindex == LOOPBACK_IFINDEX)
                 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);
+        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;
@@ -911,97 +925,38 @@ int manager_recv(Manager *m, int fd, DnsProtocol protocol, DnsPacket **ret) {
         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;
+static int sendmsg_loop(int fd, struct msghdr *mh, int flags) {
         int r;
 
-        r = manager_recv(m, fd, DNS_PROTOCOL_DNS, &p);
-        if (r <= 0)
-                return r;
+        assert(fd >= 0);
+        assert(mh);
 
-        if (dns_packet_validate_reply(p) > 0) {
-                t = hashmap_get(m->dns_transactions, UINT_TO_PTR(DNS_PACKET_ID(p)));
-                if (!t)
+        for (;;) {
+                if (sendmsg(fd, mh, flags) >= 0)
                         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;
+                if (errno == EINTR)
+                        continue;
 
-        m->dns_ipv6_fd = socket(AF_INET6, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
-        if (m->dns_ipv6_fd < 0)
-                return -errno;
+                if (errno != EAGAIN)
+                        return -errno;
 
-        r = setsockopt(m->dns_ipv6_fd, IPPROTO_IPV6, IPV6_RECVPKTINFO, &one, sizeof(one));
-        if (r < 0) {
-                r = -errno;
-                goto fail;
+                r = fd_wait_for_event(fd, POLLOUT, SEND_TIMEOUT_USEC);
+                if (r < 0)
+                        return r;
+                if (r == 0)
+                        return -ETIMEDOUT;
         }
-
-        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) {
+static int write_loop(int fd, void *message, size_t length) {
         int r;
 
         assert(fd >= 0);
-        assert(mh);
+        assert(message);
 
         for (;;) {
-                if (sendmsg(fd, mh, flags) >= 0)
+                if (write(fd, message, length) >= 0)
                         return 0;
 
                 if (errno == EINTR)
@@ -1018,6 +973,18 @@ static int sendmsg_loop(int fd, struct msghdr *mh, int flags) {
         }
 }
 
+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,
@@ -1245,407 +1212,6 @@ uint32_t manager_find_mtu(Manager *m) {
         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;
-}
-
-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->flags & IFF_LOOPBACK)
-                return 1;
-
-        return 0;
-}
-
 int manager_find_ifindex(Manager *m, int family, const union in_addr_union *in_addr) {
         LinkAddress *a;
 
@@ -1770,15 +1336,25 @@ void manager_verify_all(Manager *m) {
 }
 
 void manager_flush_dns_servers(Manager *m, DnsServerType t) {
+        DnsServer *s;
+
         assert(m);
 
         if (t == DNS_SERVER_SYSTEM)
-                while (m->dns_servers)
-                        dns_server_free(m->dns_servers);
+                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)
-                        dns_server_free(m->fallback_dns_servers);
+                while (m->fallback_dns_servers) {
+                        s = m->fallback_dns_servers;
+
+                        LIST_REMOVE(servers, m->fallback_dns_servers, s);
+                        dns_server_unref(s);
+                }
 }
 
 static const char* const support_table[_SUPPORT_MAX] = {