src/resolve/resolved-llmnr.c - systemd-stable - Rivoreo Source Code Repositories

 /***
   This file is part of systemd.

   Copyright 2014 Tom Gundersen <teg@jklm.no>

   systemd is free software; you can redistribute it and/or modify it
   under the terms of the GNU Lesser General Public License as published by
   the Free Software Foundation; either version 2.1 of the License, or
   (at your option) any later version.

   systemd is distributed in the hope that it will be useful, but
   WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public License
   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  ***/

 #include <netinet/in.h>
 #include <resolv.h>

 #include "fd-util.h"
 #include "resolved-llmnr.h"
 #include "resolved-manager.h"

 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);
 }

 int manager_llmnr_start(Manager *m) {
         int r;

         assert(m);

         if (m->llmnr_support == RESOLVE_SUPPORT_NO)
                 return 0;

         r = manager_llmnr_ipv4_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;

         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("Another LLMNR responder prohibits binding the socket to the same port. Turning off LLMNR support.");
         m->llmnr_support = RESOLVE_SUPPORT_NO;
         manager_llmnr_stop(m);

         return 0;
 }

 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;

         assert(s);
         assert(fd >= 0);
         assert(m);

         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.");
         else if (dns_packet_validate_reply(p) > 0) {
                 log_debug("Got LLMNR UDP 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 LLMNR UDP query packet for id %u", DNS_PACKET_ID(p));

                 dns_scope_process_query(scope, NULL, p);
         } else
                 log_debug("Invalid LLMNR UDP packet, ignoring.");

         return 0;
 }

 int manager_llmnr_ipv4_udp_fd(Manager *m) {
         union sockaddr_union sa = {
                 .in.sin_family = AF_INET,
                 .in.sin_port = htobe16(LLMNR_PORT),
         };
         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 log_error_errno(errno, "LLMNR-IPv4(UDP): Failed to create socket: %m");

         /* 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 = log_error_errno(errno, "LLMNR-IPv4(UDP): Failed to set IP_TTL: %m");
                 goto fail;
         }

         r = setsockopt(m->llmnr_ipv4_udp_fd, IPPROTO_IP, IP_MULTICAST_TTL, &ttl, sizeof(ttl));
         if (r < 0) {
                 r = log_error_errno(errno, "LLMNR-IPv4(UDP): Failed to set IP_MULTICAST_TTL: %m");
                 goto fail;
         }

         r = setsockopt(m->llmnr_ipv4_udp_fd, IPPROTO_IP, IP_MULTICAST_LOOP, &one, sizeof(one));
         if (r < 0) {
                 r = log_error_errno(errno, "LLMNR-IPv4(UDP): Failed to set IP_MULTICAST_LOOP: %m");
                 goto fail;
         }

         r = setsockopt(m->llmnr_ipv4_udp_fd, IPPROTO_IP, IP_PKTINFO, &one, sizeof(one));
         if (r < 0) {
                 r = log_error_errno(errno, "LLMNR-IPv4(UDP): Failed to set IP_PKTINFO: %m");
                 goto fail;
         }

         r = setsockopt(m->llmnr_ipv4_udp_fd, IPPROTO_IP, IP_RECVTTL, &one, sizeof(one));
         if (r < 0) {
                 r = log_error_errno(errno, "LLMNR-IPv4(UDP): Failed to set IP_RECVTTL: %m");
                 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 = log_error_errno(errno, "LLMNR-IPv4(UDP): Failed to set IP_MTU_DISCOVER: %m");
                 goto fail;
         }

         /* first try to bind without SO_REUSEADDR to detect another LLMNR responder */
         r = bind(m->llmnr_ipv4_udp_fd, &sa.sa, sizeof(sa.in));
         if (r < 0) {
                 if (errno != EADDRINUSE) {
                         r = log_error_errno(errno, "LLMNR-IPv4(UDP): Failed to bind socket: %m");
                         goto fail;
                 }

                 log_warning("LLMNR-IPv4(UDP): There appears to be another LLMNR responder running, or previously systemd-resolved crashed with some outstanding transfers.");

                 /* try again with SO_REUSEADDR */
                 r = setsockopt(m->llmnr_ipv4_udp_fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
                 if (r < 0) {
                         r = log_error_errno(errno, "LLMNR-IPv4(UDP): Failed to set SO_REUSEADDR: %m");
                         goto fail;
                 }

                 r = bind(m->llmnr_ipv4_udp_fd, &sa.sa, sizeof(sa.in));
                 if (r < 0) {
                         r = log_error_errno(errno, "LLMNR-IPv4(UDP): Failed to bind socket: %m");
                         goto fail;
                 }
         } else {
                 /* enable SO_REUSEADDR for the case that the user really wants multiple LLMNR responders */
                 r = setsockopt(m->llmnr_ipv4_udp_fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
                 if (r < 0) {
                         r = log_error_errno(errno, "LLMNR-IPv4(UDP): Failed to set SO_REUSEADDR: %m");
                         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;

         (void) sd_event_source_set_description(m->llmnr_ipv4_udp_event_source, "llmnr-ipv4-udp");

         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(LLMNR_PORT),
         };
         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 log_error_errno(errno, "LLMNR-IPv6(UDP): Failed to create socket: %m");

         r = setsockopt(m->llmnr_ipv6_udp_fd, IPPROTO_IPV6, IPV6_UNICAST_HOPS, &ttl, sizeof(ttl));
         if (r < 0) {
                 r = log_error_errno(errno, "LLMNR-IPv6(UDP): Failed to set IPV6_UNICAST_HOPS: %m");
                 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 = log_error_errno(errno, "LLMNR-IPv6(UDP): Failed to set IPV6_MULTICAST_HOPS: %m");
                 goto fail;
         }

         r = setsockopt(m->llmnr_ipv6_udp_fd, IPPROTO_IPV6, IPV6_MULTICAST_LOOP, &one, sizeof(one));
         if (r < 0) {
                 r = log_error_errno(errno, "LLMNR-IPv6(UDP): Failed to set IPV6_MULTICAST_LOOP: %m");
                 goto fail;
         }

         r = setsockopt(m->llmnr_ipv6_udp_fd, IPPROTO_IPV6, IPV6_V6ONLY, &one, sizeof(one));
         if (r < 0) {
                 r = log_error_errno(errno, "LLMNR-IPv6(UDP): Failed to set IPV6_V6ONLY: %m");
                 goto fail;
         }

         r = setsockopt(m->llmnr_ipv6_udp_fd, IPPROTO_IPV6, IPV6_RECVPKTINFO, &one, sizeof(one));
         if (r < 0) {
                 r = log_error_errno(errno, "LLMNR-IPv6(UDP): Failed to set IPV6_RECVPKTINFO: %m");
                 goto fail;
         }

         r = setsockopt(m->llmnr_ipv6_udp_fd, IPPROTO_IPV6, IPV6_RECVHOPLIMIT, &one, sizeof(one));
         if (r < 0) {
                 r = log_error_errno(errno, "LLMNR-IPv6(UDP): Failed to set IPV6_RECVHOPLIMIT: %m");
                 goto fail;
         }

         /* first try to bind without SO_REUSEADDR to detect another LLMNR responder */
         r = bind(m->llmnr_ipv6_udp_fd, &sa.sa, sizeof(sa.in6));
         if (r < 0) {
                 if (errno != EADDRINUSE) {
                         r = log_error_errno(errno, "LLMNR-IPv6(UDP): Failed to bind socket: %m");
                         goto fail;
                 }

                 log_warning("LLMNR-IPv6(UDP): There appears to be another LLMNR responder running, or previously systemd-resolved crashed with some outstanding transfers.");

                 /* try again with SO_REUSEADDR */
                 r = setsockopt(m->llmnr_ipv6_udp_fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
                 if (r < 0) {
                         r = log_error_errno(errno, "LLMNR-IPv6(UDP): Failed to set SO_REUSEADDR: %m");
                         goto fail;
                 }

                 r = bind(m->llmnr_ipv6_udp_fd, &sa.sa, sizeof(sa.in6));
                 if (r < 0) {
                         r = log_error_errno(errno, "LLMNR-IPv6(UDP): Failed to bind socket: %m");
                         goto fail;
                 }
         } else {
                 /* enable SO_REUSEADDR for the case that the user really wants multiple LLMNR responders */
                 r = setsockopt(m->llmnr_ipv6_udp_fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
                 if (r < 0) {
                         r = log_error_errno(errno, "LLMNR-IPv6(UDP): Failed to set SO_REUSEADDR: %m");
                         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)
                 goto fail;

         (void) sd_event_source_set_description(m->llmnr_ipv6_udp_event_source, "llmnr-ipv6-udp");

         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);
         assert(s->read_packet);

         scope = manager_find_scope(s->manager, s->read_packet);
         if (!scope)
                 log_warning("Got LLMNR TCP packet on unknown scope. Ignoring.");
         else if (dns_packet_validate_query(s->read_packet) > 0) {
                 log_debug("Got LLMNR TCP query packet for id %u", DNS_PACKET_ID(s->read_packet));

                 dns_scope_process_query(scope, s, s->read_packet);
         } else
                 log_debug("Invalid LLMNR TCP packet, ignoring.");

         dns_stream_unref(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 (IN_SET(errno, EAGAIN, 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(LLMNR_PORT),
         };
         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 log_error_errno(errno, "LLMNR-IPv4(TCP): Failed to create socket: %m");

         /* 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 = log_error_errno(errno, "LLMNR-IPv4(TCP): Failed to set IP_TTL: %m");
                 goto fail;
         }

         r = setsockopt(m->llmnr_ipv4_tcp_fd, IPPROTO_IP, IP_PKTINFO, &one, sizeof(one));
         if (r < 0) {
                 r = log_error_errno(errno, "LLMNR-IPv4(TCP): Failed to set IP_PKTINFO: %m");
                 goto fail;
         }

         r = setsockopt(m->llmnr_ipv4_tcp_fd, IPPROTO_IP, IP_RECVTTL, &one, sizeof(one));
         if (r < 0) {
                 r = log_error_errno(errno, "LLMNR-IPv4(TCP): Failed to set IP_RECVTTL: %m");
                 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 = log_error_errno(errno, "LLMNR-IPv4(TCP): Failed to set IP_MTU_DISCOVER: %m");
                 goto fail;
         }

         /* first try to bind without SO_REUSEADDR to detect another LLMNR responder */
         r = bind(m->llmnr_ipv4_tcp_fd, &sa.sa, sizeof(sa.in));
         if (r < 0) {
                 if (errno != EADDRINUSE) {
                         r = log_error_errno(errno, "LLMNR-IPv4(TCP): Failed to bind socket: %m");
                         goto fail;
                 }

                 log_warning("LLMNR-IPv4(TCP): There appears to be another LLMNR responder running, or previously systemd-resolved crashed with some outstanding transfers.");

                 /* try again with SO_REUSEADDR */
                 r = setsockopt(m->llmnr_ipv4_tcp_fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
                 if (r < 0) {
                         r = log_error_errno(errno, "LLMNR-IPv4(TCP): Failed to set SO_REUSEADDR: %m");
                         goto fail;
                 }

                 r = bind(m->llmnr_ipv4_tcp_fd, &sa.sa, sizeof(sa.in));
                 if (r < 0) {
                         r = log_error_errno(errno, "LLMNR-IPv4(TCP): Failed to bind socket: %m");
                         goto fail;
                 }
         } else {
                 /* enable SO_REUSEADDR for the case that the user really wants multiple LLMNR responders */
                 r = setsockopt(m->llmnr_ipv4_tcp_fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
                 if (r < 0) {
                         r = log_error_errno(errno, "LLMNR-IPv4(TCP): Failed to set SO_REUSEADDR: %m");
                         goto fail;
                 }
         }

         r = listen(m->llmnr_ipv4_tcp_fd, SOMAXCONN);
         if (r < 0) {
                 r = log_error_errno(errno, "LLMNR-IPv4(TCP): Failed to listen the stream: %m");
                 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;

         (void) sd_event_source_set_description(m->llmnr_ipv4_tcp_event_source, "llmnr-ipv4-tcp");

         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(LLMNR_PORT),
         };
         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 log_error_errno(errno, "LLMNR-IPv6(TCP): Failed to create socket: %m");

         /* 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 = log_error_errno(errno, "LLMNR-IPv6(TCP): Failed to set IPV6_UNICAST_HOPS: %m");
                 goto fail;
         }

         r = setsockopt(m->llmnr_ipv6_tcp_fd, IPPROTO_IPV6, IPV6_V6ONLY, &one, sizeof(one));
         if (r < 0) {
                 r = log_error_errno(errno, "LLMNR-IPv6(TCP): Failed to set IPV6_V6ONLY: %m");
                 goto fail;
         }

         r = setsockopt(m->llmnr_ipv6_tcp_fd, IPPROTO_IPV6, IPV6_RECVPKTINFO, &one, sizeof(one));
         if (r < 0) {
                 r = log_error_errno(errno, "LLMNR-IPv6(TCP): Failed to set IPV6_RECVPKTINFO: %m");
                 goto fail;
         }

         r = setsockopt(m->llmnr_ipv6_tcp_fd, IPPROTO_IPV6, IPV6_RECVHOPLIMIT, &one, sizeof(one));
         if (r < 0) {
                 r = log_error_errno(errno, "LLMNR-IPv6(TCP): Failed to set IPV6_RECVHOPLIMIT: %m");
                 goto fail;
         }

         /* first try to bind without SO_REUSEADDR to detect another LLMNR responder */
         r = bind(m->llmnr_ipv6_tcp_fd, &sa.sa, sizeof(sa.in6));
         if (r < 0) {
                 if (errno != EADDRINUSE) {
                         r = log_error_errno(errno, "LLMNR-IPv6(TCP): Failed to bind socket: %m");
                         goto fail;
                 }

                 log_warning("LLMNR-IPv6(TCP): There appears to be another LLMNR responder running, or previously systemd-resolved crashed with some outstanding transfers.");

                 /* try again with SO_REUSEADDR */
                 r = setsockopt(m->llmnr_ipv6_tcp_fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
                 if (r < 0) {
                         r = log_error_errno(errno, "LLMNR-IPv6(TCP): Failed to set SO_REUSEADDR: %m");
                         goto fail;
                 }

                 r = bind(m->llmnr_ipv6_tcp_fd, &sa.sa, sizeof(sa.in6));
                 if (r < 0) {
                         r = log_error_errno(errno, "LLMNR-IPv6(TCP): Failed to bind socket: %m");
                         goto fail;
                 }
         } else {
                 /* enable SO_REUSEADDR for the case that the user really wants multiple LLMNR responders */
                 r = setsockopt(m->llmnr_ipv6_tcp_fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
                 if (r < 0) {
                         r = log_error_errno(errno, "LLMNR-IPv6(TCP): Failed to set SO_REUSEADDR: %m");
                         goto fail;
                 }
         }

         r = listen(m->llmnr_ipv6_tcp_fd, SOMAXCONN);
         if (r < 0) {
                 r = log_error_errno(errno, "LLMNR-IPv6(TCP): Failed to listen the stream: %m");
                 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)
                 goto fail;

         (void) sd_event_source_set_description(m->llmnr_ipv6_tcp_event_source, "llmnr-ipv6-tcp");

         return m->llmnr_ipv6_tcp_fd;

 fail:
         m->llmnr_ipv6_tcp_fd = safe_close(m->llmnr_ipv6_tcp_fd);
         return r;
 }
	/***
	This file is part of systemd.

	Copyright 2014 Tom Gundersen <teg@jklm.no>

	systemd is free software; you can redistribute it and/or modify it
	under the terms of the GNU Lesser General Public License as published by
	the Free Software Foundation; either version 2.1 of the License, or
	(at your option) any later version.

	systemd is distributed in the hope that it will be useful, but
	WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	Lesser General Public License for more details.

	You should have received a copy of the GNU Lesser General Public License
	along with systemd; If not, see <http://www.gnu.org/licenses/>.
	***/

	#include <netinet/in.h>
	#include <resolv.h>

	#include "fd-util.h"
	#include "resolved-llmnr.h"
	#include "resolved-manager.h"

	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);
	}

	int manager_llmnr_start(Manager *m) {
	int r;

	assert(m);

	if (m->llmnr_support == RESOLVE_SUPPORT_NO)
	return 0;

	r = manager_llmnr_ipv4_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;

	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("Another LLMNR responder prohibits binding the socket to the same port. Turning off LLMNR support.");
	m->llmnr_support = RESOLVE_SUPPORT_NO;
	manager_llmnr_stop(m);

	return 0;
	}

	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;

	assert(s);
	assert(fd >= 0);
	assert(m);

	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.");
	else if (dns_packet_validate_reply(p) > 0) {
	log_debug("Got LLMNR UDP 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 LLMNR UDP query packet for id %u", DNS_PACKET_ID(p));

	dns_scope_process_query(scope, NULL, p);
	} else
	log_debug("Invalid LLMNR UDP packet, ignoring.");

	return 0;
	}

	int manager_llmnr_ipv4_udp_fd(Manager *m) {
	union sockaddr_union sa = {
	.in.sin_family = AF_INET,
	.in.sin_port = htobe16(LLMNR_PORT),
	};
	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 log_error_errno(errno, "LLMNR-IPv4(UDP): Failed to create socket: %m");

	/* 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 = log_error_errno(errno, "LLMNR-IPv4(UDP): Failed to set IP_TTL: %m");
	goto fail;
	}

	r = setsockopt(m->llmnr_ipv4_udp_fd, IPPROTO_IP, IP_MULTICAST_TTL, &ttl, sizeof(ttl));
	if (r < 0) {
	r = log_error_errno(errno, "LLMNR-IPv4(UDP): Failed to set IP_MULTICAST_TTL: %m");
	goto fail;
	}

	r = setsockopt(m->llmnr_ipv4_udp_fd, IPPROTO_IP, IP_MULTICAST_LOOP, &one, sizeof(one));
	if (r < 0) {
	r = log_error_errno(errno, "LLMNR-IPv4(UDP): Failed to set IP_MULTICAST_LOOP: %m");
	goto fail;
	}

	r = setsockopt(m->llmnr_ipv4_udp_fd, IPPROTO_IP, IP_PKTINFO, &one, sizeof(one));
	if (r < 0) {
	r = log_error_errno(errno, "LLMNR-IPv4(UDP): Failed to set IP_PKTINFO: %m");
	goto fail;
	}

	r = setsockopt(m->llmnr_ipv4_udp_fd, IPPROTO_IP, IP_RECVTTL, &one, sizeof(one));
	if (r < 0) {
	r = log_error_errno(errno, "LLMNR-IPv4(UDP): Failed to set IP_RECVTTL: %m");
	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 = log_error_errno(errno, "LLMNR-IPv4(UDP): Failed to set IP_MTU_DISCOVER: %m");
	goto fail;
	}

	/* first try to bind without SO_REUSEADDR to detect another LLMNR responder */
	r = bind(m->llmnr_ipv4_udp_fd, &sa.sa, sizeof(sa.in));
	if (r < 0) {
	if (errno != EADDRINUSE) {
	r = log_error_errno(errno, "LLMNR-IPv4(UDP): Failed to bind socket: %m");
	goto fail;
	}

	log_warning("LLMNR-IPv4(UDP): There appears to be another LLMNR responder running, or previously systemd-resolved crashed with some outstanding transfers.");

	/* try again with SO_REUSEADDR */
	r = setsockopt(m->llmnr_ipv4_udp_fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
	if (r < 0) {
	r = log_error_errno(errno, "LLMNR-IPv4(UDP): Failed to set SO_REUSEADDR: %m");
	goto fail;
	}

	r = bind(m->llmnr_ipv4_udp_fd, &sa.sa, sizeof(sa.in));
	if (r < 0) {
	r = log_error_errno(errno, "LLMNR-IPv4(UDP): Failed to bind socket: %m");
	goto fail;
	}
	} else {
	/* enable SO_REUSEADDR for the case that the user really wants multiple LLMNR responders */
	r = setsockopt(m->llmnr_ipv4_udp_fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
	if (r < 0) {
	r = log_error_errno(errno, "LLMNR-IPv4(UDP): Failed to set SO_REUSEADDR: %m");
	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;

	(void) sd_event_source_set_description(m->llmnr_ipv4_udp_event_source, "llmnr-ipv4-udp");

	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(LLMNR_PORT),
	};
	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 log_error_errno(errno, "LLMNR-IPv6(UDP): Failed to create socket: %m");

	r = setsockopt(m->llmnr_ipv6_udp_fd, IPPROTO_IPV6, IPV6_UNICAST_HOPS, &ttl, sizeof(ttl));
	if (r < 0) {
	r = log_error_errno(errno, "LLMNR-IPv6(UDP): Failed to set IPV6_UNICAST_HOPS: %m");
	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 = log_error_errno(errno, "LLMNR-IPv6(UDP): Failed to set IPV6_MULTICAST_HOPS: %m");
	goto fail;
	}

	r = setsockopt(m->llmnr_ipv6_udp_fd, IPPROTO_IPV6, IPV6_MULTICAST_LOOP, &one, sizeof(one));
	if (r < 0) {
	r = log_error_errno(errno, "LLMNR-IPv6(UDP): Failed to set IPV6_MULTICAST_LOOP: %m");
	goto fail;
	}

	r = setsockopt(m->llmnr_ipv6_udp_fd, IPPROTO_IPV6, IPV6_V6ONLY, &one, sizeof(one));
	if (r < 0) {
	r = log_error_errno(errno, "LLMNR-IPv6(UDP): Failed to set IPV6_V6ONLY: %m");
	goto fail;
	}

	r = setsockopt(m->llmnr_ipv6_udp_fd, IPPROTO_IPV6, IPV6_RECVPKTINFO, &one, sizeof(one));
	if (r < 0) {
	r = log_error_errno(errno, "LLMNR-IPv6(UDP): Failed to set IPV6_RECVPKTINFO: %m");
	goto fail;
	}

	r = setsockopt(m->llmnr_ipv6_udp_fd, IPPROTO_IPV6, IPV6_RECVHOPLIMIT, &one, sizeof(one));
	if (r < 0) {
	r = log_error_errno(errno, "LLMNR-IPv6(UDP): Failed to set IPV6_RECVHOPLIMIT: %m");
	goto fail;
	}

	/* first try to bind without SO_REUSEADDR to detect another LLMNR responder */
	r = bind(m->llmnr_ipv6_udp_fd, &sa.sa, sizeof(sa.in6));
	if (r < 0) {
	if (errno != EADDRINUSE) {
	r = log_error_errno(errno, "LLMNR-IPv6(UDP): Failed to bind socket: %m");
	goto fail;
	}

	log_warning("LLMNR-IPv6(UDP): There appears to be another LLMNR responder running, or previously systemd-resolved crashed with some outstanding transfers.");

	/* try again with SO_REUSEADDR */
	r = setsockopt(m->llmnr_ipv6_udp_fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
	if (r < 0) {
	r = log_error_errno(errno, "LLMNR-IPv6(UDP): Failed to set SO_REUSEADDR: %m");
	goto fail;
	}

	r = bind(m->llmnr_ipv6_udp_fd, &sa.sa, sizeof(sa.in6));
	if (r < 0) {
	r = log_error_errno(errno, "LLMNR-IPv6(UDP): Failed to bind socket: %m");
	goto fail;
	}
	} else {
	/* enable SO_REUSEADDR for the case that the user really wants multiple LLMNR responders */
	r = setsockopt(m->llmnr_ipv6_udp_fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
	if (r < 0) {
	r = log_error_errno(errno, "LLMNR-IPv6(UDP): Failed to set SO_REUSEADDR: %m");
	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)
	goto fail;

	(void) sd_event_source_set_description(m->llmnr_ipv6_udp_event_source, "llmnr-ipv6-udp");

	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);
	assert(s->read_packet);

	scope = manager_find_scope(s->manager, s->read_packet);
	if (!scope)
	log_warning("Got LLMNR TCP packet on unknown scope. Ignoring.");
	else if (dns_packet_validate_query(s->read_packet) > 0) {
	log_debug("Got LLMNR TCP query packet for id %u", DNS_PACKET_ID(s->read_packet));

	dns_scope_process_query(scope, s, s->read_packet);
	} else
	log_debug("Invalid LLMNR TCP packet, ignoring.");

	dns_stream_unref(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 (IN_SET(errno, EAGAIN, 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(LLMNR_PORT),
	};
	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 log_error_errno(errno, "LLMNR-IPv4(TCP): Failed to create socket: %m");

	/* 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 = log_error_errno(errno, "LLMNR-IPv4(TCP): Failed to set IP_TTL: %m");
	goto fail;
	}

	r = setsockopt(m->llmnr_ipv4_tcp_fd, IPPROTO_IP, IP_PKTINFO, &one, sizeof(one));
	if (r < 0) {
	r = log_error_errno(errno, "LLMNR-IPv4(TCP): Failed to set IP_PKTINFO: %m");
	goto fail;
	}

	r = setsockopt(m->llmnr_ipv4_tcp_fd, IPPROTO_IP, IP_RECVTTL, &one, sizeof(one));
	if (r < 0) {
	r = log_error_errno(errno, "LLMNR-IPv4(TCP): Failed to set IP_RECVTTL: %m");
	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 = log_error_errno(errno, "LLMNR-IPv4(TCP): Failed to set IP_MTU_DISCOVER: %m");
	goto fail;
	}

	/* first try to bind without SO_REUSEADDR to detect another LLMNR responder */
	r = bind(m->llmnr_ipv4_tcp_fd, &sa.sa, sizeof(sa.in));
	if (r < 0) {
	if (errno != EADDRINUSE) {
	r = log_error_errno(errno, "LLMNR-IPv4(TCP): Failed to bind socket: %m");
	goto fail;
	}

	log_warning("LLMNR-IPv4(TCP): There appears to be another LLMNR responder running, or previously systemd-resolved crashed with some outstanding transfers.");

	/* try again with SO_REUSEADDR */
	r = setsockopt(m->llmnr_ipv4_tcp_fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
	if (r < 0) {
	r = log_error_errno(errno, "LLMNR-IPv4(TCP): Failed to set SO_REUSEADDR: %m");
	goto fail;
	}

	r = bind(m->llmnr_ipv4_tcp_fd, &sa.sa, sizeof(sa.in));
	if (r < 0) {
	r = log_error_errno(errno, "LLMNR-IPv4(TCP): Failed to bind socket: %m");
	goto fail;
	}
	} else {
	/* enable SO_REUSEADDR for the case that the user really wants multiple LLMNR responders */
	r = setsockopt(m->llmnr_ipv4_tcp_fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
	if (r < 0) {
	r = log_error_errno(errno, "LLMNR-IPv4(TCP): Failed to set SO_REUSEADDR: %m");
	goto fail;
	}
	}

	r = listen(m->llmnr_ipv4_tcp_fd, SOMAXCONN);
	if (r < 0) {
	r = log_error_errno(errno, "LLMNR-IPv4(TCP): Failed to listen the stream: %m");
	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;

	(void) sd_event_source_set_description(m->llmnr_ipv4_tcp_event_source, "llmnr-ipv4-tcp");

	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(LLMNR_PORT),
	};
	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 log_error_errno(errno, "LLMNR-IPv6(TCP): Failed to create socket: %m");

	/* 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 = log_error_errno(errno, "LLMNR-IPv6(TCP): Failed to set IPV6_UNICAST_HOPS: %m");
	goto fail;
	}

	r = setsockopt(m->llmnr_ipv6_tcp_fd, IPPROTO_IPV6, IPV6_V6ONLY, &one, sizeof(one));
	if (r < 0) {
	r = log_error_errno(errno, "LLMNR-IPv6(TCP): Failed to set IPV6_V6ONLY: %m");
	goto fail;
	}

	r = setsockopt(m->llmnr_ipv6_tcp_fd, IPPROTO_IPV6, IPV6_RECVPKTINFO, &one, sizeof(one));
	if (r < 0) {
	r = log_error_errno(errno, "LLMNR-IPv6(TCP): Failed to set IPV6_RECVPKTINFO: %m");
	goto fail;
	}

	r = setsockopt(m->llmnr_ipv6_tcp_fd, IPPROTO_IPV6, IPV6_RECVHOPLIMIT, &one, sizeof(one));
	if (r < 0) {
	r = log_error_errno(errno, "LLMNR-IPv6(TCP): Failed to set IPV6_RECVHOPLIMIT: %m");
	goto fail;
	}

	/* first try to bind without SO_REUSEADDR to detect another LLMNR responder */
	r = bind(m->llmnr_ipv6_tcp_fd, &sa.sa, sizeof(sa.in6));
	if (r < 0) {
	if (errno != EADDRINUSE) {
	r = log_error_errno(errno, "LLMNR-IPv6(TCP): Failed to bind socket: %m");
	goto fail;
	}

	log_warning("LLMNR-IPv6(TCP): There appears to be another LLMNR responder running, or previously systemd-resolved crashed with some outstanding transfers.");

	/* try again with SO_REUSEADDR */
	r = setsockopt(m->llmnr_ipv6_tcp_fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
	if (r < 0) {
	r = log_error_errno(errno, "LLMNR-IPv6(TCP): Failed to set SO_REUSEADDR: %m");
	goto fail;
	}

	r = bind(m->llmnr_ipv6_tcp_fd, &sa.sa, sizeof(sa.in6));
	if (r < 0) {
	r = log_error_errno(errno, "LLMNR-IPv6(TCP): Failed to bind socket: %m");
	goto fail;
	}
	} else {
	/* enable SO_REUSEADDR for the case that the user really wants multiple LLMNR responders */
	r = setsockopt(m->llmnr_ipv6_tcp_fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
	if (r < 0) {
	r = log_error_errno(errno, "LLMNR-IPv6(TCP): Failed to set SO_REUSEADDR: %m");
	goto fail;
	}
	}

	r = listen(m->llmnr_ipv6_tcp_fd, SOMAXCONN);
	if (r < 0) {
	r = log_error_errno(errno, "LLMNR-IPv6(TCP): Failed to listen the stream: %m");
	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)
	goto fail;

	(void) sd_event_source_set_description(m->llmnr_ipv6_tcp_event_source, "llmnr-ipv6-tcp");

	return m->llmnr_ipv6_tcp_fd;

	fail:
	m->llmnr_ipv6_tcp_fd = safe_close(m->llmnr_ipv6_tcp_fd);
	return r;
	}