[thirdparty/systemd.git] / src / resolve / resolved-llmnr.c

/* SPDX-License-Identifier: LGPL-2.1+ */
/***
  Copyright © 2014 Tom Gundersen <teg@jklm.no>
 ***/

#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;

        if (manager_our_packet(m, p))
                return 0;

        scope = manager_find_scope(m, p);
        if (!scope) {
                log_debug("Got LLMNR UDP packet on unknown scope. Ignoring.");
                return 0;
        }

        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_debug("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, NULL);
        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;
}
Commit	Line	Data
53e1b683	1	/* SPDX-License-Identifier: LGPL-2.1+ */
5f402ae8	2	/***
96b2fb93	3	Copyright © 2014 Tom Gundersen <teg@jklm.no>
5f402ae8 DM	4	***/
5f402ae8 DM	5
5f402ae8	6	#include <netinet/in.h>
cf0fbc49	7	#include <resolv.h>
5f402ae8	8
3ffd4af2	9	#include "fd-util.h"
5f402ae8	10	#include "resolved-llmnr.h"
3ffd4af2	11	#include "resolved-manager.h"
5f402ae8 DM	12
	13	void manager_llmnr_stop(Manager *m) {
	14	assert(m);
	15
	16	m->llmnr_ipv4_udp_event_source = sd_event_source_unref(m->llmnr_ipv4_udp_event_source);
	17	m->llmnr_ipv4_udp_fd = safe_close(m->llmnr_ipv4_udp_fd);
	18
	19	m->llmnr_ipv6_udp_event_source = sd_event_source_unref(m->llmnr_ipv6_udp_event_source);
	20	m->llmnr_ipv6_udp_fd = safe_close(m->llmnr_ipv6_udp_fd);
	21
	22	m->llmnr_ipv4_tcp_event_source = sd_event_source_unref(m->llmnr_ipv4_tcp_event_source);
	23	m->llmnr_ipv4_tcp_fd = safe_close(m->llmnr_ipv4_tcp_fd);
	24
	25	m->llmnr_ipv6_tcp_event_source = sd_event_source_unref(m->llmnr_ipv6_tcp_event_source);
	26	m->llmnr_ipv6_tcp_fd = safe_close(m->llmnr_ipv6_tcp_fd);
	27	}
	28
	29	int manager_llmnr_start(Manager *m) {
	30	int r;
	31
	32	assert(m);
	33
af49ca27	34	if (m->llmnr_support == RESOLVE_SUPPORT_NO)
5f402ae8 DM	35	return 0;
	36
	37	r = manager_llmnr_ipv4_udp_fd(m);
	38	if (r == -EADDRINUSE)
	39	goto eaddrinuse;
	40	if (r < 0)
	41	return r;
	42
	43	r = manager_llmnr_ipv4_tcp_fd(m);
	44	if (r == -EADDRINUSE)
	45	goto eaddrinuse;
	46	if (r < 0)
	47	return r;
	48
	49	if (socket_ipv6_is_supported()) {
	50	r = manager_llmnr_ipv6_udp_fd(m);
	51	if (r == -EADDRINUSE)
	52	goto eaddrinuse;
	53	if (r < 0)
	54	return r;
	55
	56	r = manager_llmnr_ipv6_tcp_fd(m);
	57	if (r == -EADDRINUSE)
	58	goto eaddrinuse;
	59	if (r < 0)
	60	return r;
	61	}
	62
	63	return 0;
	64
	65	eaddrinuse:
007ef0a2	66	log_warning("Another LLMNR responder prohibits binding the socket to the same port. Turning off LLMNR support.");
af49ca27	67	m->llmnr_support = RESOLVE_SUPPORT_NO;
5f402ae8 DM	68	manager_llmnr_stop(m);
	69
	70	return 0;
	71	}
	72
	73	static int on_llmnr_packet(sd_event_source s, int fd, uint32_t revents, void userdata) {
	74	_cleanup_(dns_packet_unrefp) DnsPacket *p = NULL;
	75	DnsTransaction *t = NULL;
	76	Manager *m = userdata;
	77	DnsScope *scope;
	78	int r;
	79
b30bf55d LP	80	assert(s);
	81	assert(fd >= 0);
	82	assert(m);
	83
5f402ae8 DM	84	r = manager_recv(m, fd, DNS_PROTOCOL_LLMNR, &p);
	85	if (r <= 0)
	86	return r;
	87
6cae1ebe LP	88	if (manager_our_packet(m, p))
	89	return 0;
	90
5f402ae8	91	scope = manager_find_scope(m, p);
f1b1a5c4 LP	92	if (!scope) {
	93	log_debug("Got LLMNR UDP packet on unknown scope. Ignoring.");
	94	return 0;
	95	}
	96
	97	if (dns_packet_validate_reply(p) > 0) {
b30bf55d	98	log_debug("Got LLMNR UDP reply packet for id %u", DNS_PACKET_ID(p));
5f402ae8 DM	99
	100	dns_scope_check_conflicts(scope, p);
	101
	102	t = hashmap_get(m->dns_transactions, UINT_TO_PTR(DNS_PACKET_ID(p)));
	103	if (t)
	104	dns_transaction_process_reply(t, p);
	105
	106	} else if (dns_packet_validate_query(p) > 0) {
b30bf55d	107	log_debug("Got LLMNR UDP query packet for id %u", DNS_PACKET_ID(p));
5f402ae8 DM	108
	109	dns_scope_process_query(scope, NULL, p);
	110	} else
2c6bf498	111	log_debug("Invalid LLMNR UDP packet, ignoring.");
5f402ae8 DM	112
	113	return 0;
	114	}
	115
	116	int manager_llmnr_ipv4_udp_fd(Manager *m) {
	117	union sockaddr_union sa = {
	118	.in.sin_family = AF_INET,
22a37591	119	.in.sin_port = htobe16(LLMNR_PORT),
5f402ae8 DM	120	};
	121	static const int one = 1, pmtu = IP_PMTUDISC_DONT, ttl = 255;
	122	int r;
	123
	124	assert(m);
	125
	126	if (m->llmnr_ipv4_udp_fd >= 0)
	127	return m->llmnr_ipv4_udp_fd;
	128
	129	m->llmnr_ipv4_udp_fd = socket(AF_INET, SOCK_DGRAM\|SOCK_CLOEXEC\|SOCK_NONBLOCK, 0);
	130	if (m->llmnr_ipv4_udp_fd < 0)
007ef0a2	131	return log_error_errno(errno, "LLMNR-IPv4(UDP): Failed to create socket: %m");
5f402ae8 DM	132
	133	/* RFC 4795, section 2.5 recommends setting the TTL of UDP packets to 255. */
	134	r = setsockopt(m->llmnr_ipv4_udp_fd, IPPROTO_IP, IP_TTL, &ttl, sizeof(ttl));
	135	if (r < 0) {
007ef0a2	136	r = log_error_errno(errno, "LLMNR-IPv4(UDP): Failed to set IP_TTL: %m");
5f402ae8 DM	137	goto fail;
	138	}
	139
	140	r = setsockopt(m->llmnr_ipv4_udp_fd, IPPROTO_IP, IP_MULTICAST_TTL, &ttl, sizeof(ttl));
	141	if (r < 0) {
007ef0a2	142	r = log_error_errno(errno, "LLMNR-IPv4(UDP): Failed to set IP_MULTICAST_TTL: %m");
5f402ae8 DM	143	goto fail;
	144	}
	145
	146	r = setsockopt(m->llmnr_ipv4_udp_fd, IPPROTO_IP, IP_MULTICAST_LOOP, &one, sizeof(one));
	147	if (r < 0) {
007ef0a2	148	r = log_error_errno(errno, "LLMNR-IPv4(UDP): Failed to set IP_MULTICAST_LOOP: %m");
5f402ae8 DM	149	goto fail;
	150	}
	151
	152	r = setsockopt(m->llmnr_ipv4_udp_fd, IPPROTO_IP, IP_PKTINFO, &one, sizeof(one));
	153	if (r < 0) {
007ef0a2	154	r = log_error_errno(errno, "LLMNR-IPv4(UDP): Failed to set IP_PKTINFO: %m");
5f402ae8 DM	155	goto fail;
	156	}
	157
	158	r = setsockopt(m->llmnr_ipv4_udp_fd, IPPROTO_IP, IP_RECVTTL, &one, sizeof(one));
	159	if (r < 0) {
007ef0a2	160	r = log_error_errno(errno, "LLMNR-IPv4(UDP): Failed to set IP_RECVTTL: %m");
5f402ae8 DM	161	goto fail;
	162	}
	163
	164	/* Disable Don't-Fragment bit in the IP header */
	165	r = setsockopt(m->llmnr_ipv4_udp_fd, IPPROTO_IP, IP_MTU_DISCOVER, &pmtu, sizeof(pmtu));
	166	if (r < 0) {
007ef0a2	167	r = log_error_errno(errno, "LLMNR-IPv4(UDP): Failed to set IP_MTU_DISCOVER: %m");
5f402ae8 DM	168	goto fail;
	169	}
	170
007ef0a2	171	/* first try to bind without SO_REUSEADDR to detect another LLMNR responder */
5f402ae8 DM	172	r = bind(m->llmnr_ipv4_udp_fd, &sa.sa, sizeof(sa.in));
5f402ae8 DM	173	if (r < 0) {
007ef0a2 YW	174	if (errno != EADDRINUSE) {
	175	r = log_error_errno(errno, "LLMNR-IPv4(UDP): Failed to bind socket: %m");
	176	goto fail;
	177	}
	178
	179	log_warning("LLMNR-IPv4(UDP): There appears to be another LLMNR responder running, or previously systemd-resolved crashed with some outstanding transfers.");
	180
	181	/* try again with SO_REUSEADDR */
	182	r = setsockopt(m->llmnr_ipv4_udp_fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
	183	if (r < 0) {
	184	r = log_error_errno(errno, "LLMNR-IPv4(UDP): Failed to set SO_REUSEADDR: %m");
	185	goto fail;
	186	}
	187
	188	r = bind(m->llmnr_ipv4_udp_fd, &sa.sa, sizeof(sa.in));
	189	if (r < 0) {
	190	r = log_error_errno(errno, "LLMNR-IPv4(UDP): Failed to bind socket: %m");
	191	goto fail;
	192	}
	193	} else {
	194	/* enable SO_REUSEADDR for the case that the user really wants multiple LLMNR responders */
	195	r = setsockopt(m->llmnr_ipv4_udp_fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
	196	if (r < 0) {
	197	r = log_error_errno(errno, "LLMNR-IPv4(UDP): Failed to set SO_REUSEADDR: %m");
	198	goto fail;
	199	}
5f402ae8 DM	200	}
	201
	202	r = sd_event_add_io(m->event, &m->llmnr_ipv4_udp_event_source, m->llmnr_ipv4_udp_fd, EPOLLIN, on_llmnr_packet, m);
	203	if (r < 0)
	204	goto fail;
	205
aa4a9deb LP	206	(void) sd_event_source_set_description(m->llmnr_ipv4_udp_event_source, "llmnr-ipv4-udp");
aa4a9deb LP	207
5f402ae8 DM	208	return m->llmnr_ipv4_udp_fd;
	209
	210	fail:
	211	m->llmnr_ipv4_udp_fd = safe_close(m->llmnr_ipv4_udp_fd);
	212	return r;
	213	}
	214
	215	int manager_llmnr_ipv6_udp_fd(Manager *m) {
	216	union sockaddr_union sa = {
	217	.in6.sin6_family = AF_INET6,
22a37591	218	.in6.sin6_port = htobe16(LLMNR_PORT),
5f402ae8 DM	219	};
	220	static const int one = 1, ttl = 255;
	221	int r;
	222
	223	assert(m);
	224
	225	if (m->llmnr_ipv6_udp_fd >= 0)
	226	return m->llmnr_ipv6_udp_fd;
	227
	228	m->llmnr_ipv6_udp_fd = socket(AF_INET6, SOCK_DGRAM\|SOCK_CLOEXEC\|SOCK_NONBLOCK, 0);
	229	if (m->llmnr_ipv6_udp_fd < 0)
007ef0a2	230	return log_error_errno(errno, "LLMNR-IPv6(UDP): Failed to create socket: %m");
5f402ae8 DM	231
	232	r = setsockopt(m->llmnr_ipv6_udp_fd, IPPROTO_IPV6, IPV6_UNICAST_HOPS, &ttl, sizeof(ttl));
	233	if (r < 0) {
007ef0a2	234	r = log_error_errno(errno, "LLMNR-IPv6(UDP): Failed to set IPV6_UNICAST_HOPS: %m");
5f402ae8 DM	235	goto fail;
	236	}
	237
	238	/* RFC 4795, section 2.5 recommends setting the TTL of UDP packets to 255. */
	239	r = setsockopt(m->llmnr_ipv6_udp_fd, IPPROTO_IPV6, IPV6_MULTICAST_HOPS, &ttl, sizeof(ttl));
	240	if (r < 0) {
007ef0a2	241	r = log_error_errno(errno, "LLMNR-IPv6(UDP): Failed to set IPV6_MULTICAST_HOPS: %m");
5f402ae8 DM	242	goto fail;
	243	}
	244
	245	r = setsockopt(m->llmnr_ipv6_udp_fd, IPPROTO_IPV6, IPV6_MULTICAST_LOOP, &one, sizeof(one));
	246	if (r < 0) {
007ef0a2	247	r = log_error_errno(errno, "LLMNR-IPv6(UDP): Failed to set IPV6_MULTICAST_LOOP: %m");
5f402ae8 DM	248	goto fail;
	249	}
	250
	251	r = setsockopt(m->llmnr_ipv6_udp_fd, IPPROTO_IPV6, IPV6_V6ONLY, &one, sizeof(one));
	252	if (r < 0) {
007ef0a2	253	r = log_error_errno(errno, "LLMNR-IPv6(UDP): Failed to set IPV6_V6ONLY: %m");
5f402ae8 DM	254	goto fail;
	255	}
	256
	257	r = setsockopt(m->llmnr_ipv6_udp_fd, IPPROTO_IPV6, IPV6_RECVPKTINFO, &one, sizeof(one));
	258	if (r < 0) {
007ef0a2	259	r = log_error_errno(errno, "LLMNR-IPv6(UDP): Failed to set IPV6_RECVPKTINFO: %m");
5f402ae8 DM	260	goto fail;
	261	}
	262
	263	r = setsockopt(m->llmnr_ipv6_udp_fd, IPPROTO_IPV6, IPV6_RECVHOPLIMIT, &one, sizeof(one));
	264	if (r < 0) {
007ef0a2	265	r = log_error_errno(errno, "LLMNR-IPv6(UDP): Failed to set IPV6_RECVHOPLIMIT: %m");
5f402ae8 DM	266	goto fail;
	267	}
	268
007ef0a2	269	/* first try to bind without SO_REUSEADDR to detect another LLMNR responder */
5f402ae8 DM	270	r = bind(m->llmnr_ipv6_udp_fd, &sa.sa, sizeof(sa.in6));
5f402ae8 DM	271	if (r < 0) {
007ef0a2 YW	272	if (errno != EADDRINUSE) {
	273	r = log_error_errno(errno, "LLMNR-IPv6(UDP): Failed to bind socket: %m");
	274	goto fail;
	275	}
	276
	277	log_warning("LLMNR-IPv6(UDP): There appears to be another LLMNR responder running, or previously systemd-resolved crashed with some outstanding transfers.");
	278
	279	/* try again with SO_REUSEADDR */
	280	r = setsockopt(m->llmnr_ipv6_udp_fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
	281	if (r < 0) {
	282	r = log_error_errno(errno, "LLMNR-IPv6(UDP): Failed to set SO_REUSEADDR: %m");
	283	goto fail;
	284	}
	285
	286	r = bind(m->llmnr_ipv6_udp_fd, &sa.sa, sizeof(sa.in6));
	287	if (r < 0) {
	288	r = log_error_errno(errno, "LLMNR-IPv6(UDP): Failed to bind socket: %m");
	289	goto fail;
	290	}
	291	} else {
	292	/* enable SO_REUSEADDR for the case that the user really wants multiple LLMNR responders */
	293	r = setsockopt(m->llmnr_ipv6_udp_fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
	294	if (r < 0) {
	295	r = log_error_errno(errno, "LLMNR-IPv6(UDP): Failed to set SO_REUSEADDR: %m");
	296	goto fail;
	297	}
5f402ae8 DM	298	}
	299
	300	r = sd_event_add_io(m->event, &m->llmnr_ipv6_udp_event_source, m->llmnr_ipv6_udp_fd, EPOLLIN, on_llmnr_packet, m);
35908b98	301	if (r < 0)
5f402ae8	302	goto fail;
5f402ae8	303
aa4a9deb LP	304	(void) sd_event_source_set_description(m->llmnr_ipv6_udp_event_source, "llmnr-ipv6-udp");
aa4a9deb LP	305
5f402ae8 DM	306	return m->llmnr_ipv6_udp_fd;
	307
	308	fail:
	309	m->llmnr_ipv6_udp_fd = safe_close(m->llmnr_ipv6_udp_fd);
	310	return r;
	311	}
	312
	313	static int on_llmnr_stream_packet(DnsStream *s) {
	314	DnsScope *scope;
	315
	316	assert(s);
b30bf55d	317	assert(s->read_packet);
5f402ae8 DM	318
5f402ae8 DM	319	scope = manager_find_scope(s->manager, s->read_packet);
b30bf55d	320	if (!scope)
f1b1a5c4	321	log_debug("Got LLMNR TCP packet on unknown scope. Ignoring.");
b30bf55d LP	322	else if (dns_packet_validate_query(s->read_packet) > 0) {
b30bf55d LP	323	log_debug("Got LLMNR TCP query packet for id %u", DNS_PACKET_ID(s->read_packet));
5f402ae8 DM	324
5f402ae8 DM	325	dns_scope_process_query(scope, s, s->read_packet);
5f402ae8	326	} else
b30bf55d	327	log_debug("Invalid LLMNR TCP packet, ignoring.");
5f402ae8	328
b30bf55d	329	dns_stream_unref(s);
5f402ae8 DM	330	return 0;
	331	}
	332
	333	static int on_llmnr_stream(sd_event_source s, int fd, uint32_t revents, void userdata) {
	334	DnsStream *stream;
	335	Manager *m = userdata;
	336	int cfd, r;
	337
	338	cfd = accept4(fd, NULL, NULL, SOCK_NONBLOCK\|SOCK_CLOEXEC);
	339	if (cfd < 0) {
3742095b	340	if (IN_SET(errno, EAGAIN, EINTR))
5f402ae8 DM	341	return 0;
	342
	343	return -errno;
	344	}
	345
91ccab1e	346	r = dns_stream_new(m, &stream, DNS_PROTOCOL_LLMNR, cfd, NULL);
5f402ae8 DM	347	if (r < 0) {
	348	safe_close(cfd);
	349	return r;
	350	}
	351
	352	stream->on_packet = on_llmnr_stream_packet;
	353	return 0;
	354	}
	355
	356	int manager_llmnr_ipv4_tcp_fd(Manager *m) {
	357	union sockaddr_union sa = {
	358	.in.sin_family = AF_INET,
22a37591	359	.in.sin_port = htobe16(LLMNR_PORT),
5f402ae8 DM	360	};
	361	static const int one = 1, pmtu = IP_PMTUDISC_DONT;
	362	int r;
	363
	364	assert(m);
	365
	366	if (m->llmnr_ipv4_tcp_fd >= 0)
	367	return m->llmnr_ipv4_tcp_fd;
	368
	369	m->llmnr_ipv4_tcp_fd = socket(AF_INET, SOCK_STREAM\|SOCK_CLOEXEC\|SOCK_NONBLOCK, 0);
	370	if (m->llmnr_ipv4_tcp_fd < 0)
007ef0a2	371	return log_error_errno(errno, "LLMNR-IPv4(TCP): Failed to create socket: %m");
5f402ae8 DM	372
	373	/* RFC 4795, section 2.5. requires setting the TTL of TCP streams to 1 */
	374	r = setsockopt(m->llmnr_ipv4_tcp_fd, IPPROTO_IP, IP_TTL, &one, sizeof(one));
	375	if (r < 0) {
007ef0a2	376	r = log_error_errno(errno, "LLMNR-IPv4(TCP): Failed to set IP_TTL: %m");
5f402ae8 DM	377	goto fail;
	378	}
	379
	380	r = setsockopt(m->llmnr_ipv4_tcp_fd, IPPROTO_IP, IP_PKTINFO, &one, sizeof(one));
	381	if (r < 0) {
007ef0a2	382	r = log_error_errno(errno, "LLMNR-IPv4(TCP): Failed to set IP_PKTINFO: %m");
5f402ae8 DM	383	goto fail;
	384	}
	385
	386	r = setsockopt(m->llmnr_ipv4_tcp_fd, IPPROTO_IP, IP_RECVTTL, &one, sizeof(one));
	387	if (r < 0) {
007ef0a2	388	r = log_error_errno(errno, "LLMNR-IPv4(TCP): Failed to set IP_RECVTTL: %m");
5f402ae8 DM	389	goto fail;
	390	}
	391
	392	/* Disable Don't-Fragment bit in the IP header */
	393	r = setsockopt(m->llmnr_ipv4_tcp_fd, IPPROTO_IP, IP_MTU_DISCOVER, &pmtu, sizeof(pmtu));
	394	if (r < 0) {
007ef0a2	395	r = log_error_errno(errno, "LLMNR-IPv4(TCP): Failed to set IP_MTU_DISCOVER: %m");
5f402ae8 DM	396	goto fail;
	397	}
	398
007ef0a2	399	/* first try to bind without SO_REUSEADDR to detect another LLMNR responder */
5f402ae8 DM	400	r = bind(m->llmnr_ipv4_tcp_fd, &sa.sa, sizeof(sa.in));
5f402ae8 DM	401	if (r < 0) {
007ef0a2 YW	402	if (errno != EADDRINUSE) {
	403	r = log_error_errno(errno, "LLMNR-IPv4(TCP): Failed to bind socket: %m");
	404	goto fail;
	405	}
	406
	407	log_warning("LLMNR-IPv4(TCP): There appears to be another LLMNR responder running, or previously systemd-resolved crashed with some outstanding transfers.");
	408
	409	/* try again with SO_REUSEADDR */
	410	r = setsockopt(m->llmnr_ipv4_tcp_fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
	411	if (r < 0) {
	412	r = log_error_errno(errno, "LLMNR-IPv4(TCP): Failed to set SO_REUSEADDR: %m");
	413	goto fail;
	414	}
	415
	416	r = bind(m->llmnr_ipv4_tcp_fd, &sa.sa, sizeof(sa.in));
	417	if (r < 0) {
	418	r = log_error_errno(errno, "LLMNR-IPv4(TCP): Failed to bind socket: %m");
	419	goto fail;
	420	}
	421	} else {
	422	/* enable SO_REUSEADDR for the case that the user really wants multiple LLMNR responders */
	423	r = setsockopt(m->llmnr_ipv4_tcp_fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
	424	if (r < 0) {
	425	r = log_error_errno(errno, "LLMNR-IPv4(TCP): Failed to set SO_REUSEADDR: %m");
	426	goto fail;
	427	}
5f402ae8 DM	428	}
	429
	430	r = listen(m->llmnr_ipv4_tcp_fd, SOMAXCONN);
	431	if (r < 0) {
007ef0a2	432	r = log_error_errno(errno, "LLMNR-IPv4(TCP): Failed to listen the stream: %m");
5f402ae8 DM	433	goto fail;
	434	}
	435
	436	r = sd_event_add_io(m->event, &m->llmnr_ipv4_tcp_event_source, m->llmnr_ipv4_tcp_fd, EPOLLIN, on_llmnr_stream, m);
	437	if (r < 0)
	438	goto fail;
	439
aa4a9deb LP	440	(void) sd_event_source_set_description(m->llmnr_ipv4_tcp_event_source, "llmnr-ipv4-tcp");
aa4a9deb LP	441
5f402ae8 DM	442	return m->llmnr_ipv4_tcp_fd;
	443
	444	fail:
	445	m->llmnr_ipv4_tcp_fd = safe_close(m->llmnr_ipv4_tcp_fd);
	446	return r;
	447	}
	448
	449	int manager_llmnr_ipv6_tcp_fd(Manager *m) {
	450	union sockaddr_union sa = {
	451	.in6.sin6_family = AF_INET6,
22a37591	452	.in6.sin6_port = htobe16(LLMNR_PORT),
5f402ae8 DM	453	};
	454	static const int one = 1;
	455	int r;
	456
	457	assert(m);
	458
	459	if (m->llmnr_ipv6_tcp_fd >= 0)
	460	return m->llmnr_ipv6_tcp_fd;
	461
	462	m->llmnr_ipv6_tcp_fd = socket(AF_INET6, SOCK_STREAM\|SOCK_CLOEXEC\|SOCK_NONBLOCK, 0);
	463	if (m->llmnr_ipv6_tcp_fd < 0)
007ef0a2	464	return log_error_errno(errno, "LLMNR-IPv6(TCP): Failed to create socket: %m");
5f402ae8 DM	465
	466	/* RFC 4795, section 2.5. requires setting the TTL of TCP streams to 1 */
	467	r = setsockopt(m->llmnr_ipv6_tcp_fd, IPPROTO_IPV6, IPV6_UNICAST_HOPS, &one, sizeof(one));
	468	if (r < 0) {
007ef0a2	469	r = log_error_errno(errno, "LLMNR-IPv6(TCP): Failed to set IPV6_UNICAST_HOPS: %m");
5f402ae8 DM	470	goto fail;
	471	}
	472
	473	r = setsockopt(m->llmnr_ipv6_tcp_fd, IPPROTO_IPV6, IPV6_V6ONLY, &one, sizeof(one));
	474	if (r < 0) {
007ef0a2	475	r = log_error_errno(errno, "LLMNR-IPv6(TCP): Failed to set IPV6_V6ONLY: %m");
5f402ae8 DM	476	goto fail;
	477	}
	478
	479	r = setsockopt(m->llmnr_ipv6_tcp_fd, IPPROTO_IPV6, IPV6_RECVPKTINFO, &one, sizeof(one));
	480	if (r < 0) {
007ef0a2	481	r = log_error_errno(errno, "LLMNR-IPv6(TCP): Failed to set IPV6_RECVPKTINFO: %m");
5f402ae8 DM	482	goto fail;
	483	}
	484
	485	r = setsockopt(m->llmnr_ipv6_tcp_fd, IPPROTO_IPV6, IPV6_RECVHOPLIMIT, &one, sizeof(one));
	486	if (r < 0) {
007ef0a2	487	r = log_error_errno(errno, "LLMNR-IPv6(TCP): Failed to set IPV6_RECVHOPLIMIT: %m");
5f402ae8 DM	488	goto fail;
	489	}
	490
007ef0a2	491	/* first try to bind without SO_REUSEADDR to detect another LLMNR responder */
5f402ae8 DM	492	r = bind(m->llmnr_ipv6_tcp_fd, &sa.sa, sizeof(sa.in6));
5f402ae8 DM	493	if (r < 0) {
007ef0a2 YW	494	if (errno != EADDRINUSE) {
	495	r = log_error_errno(errno, "LLMNR-IPv6(TCP): Failed to bind socket: %m");
	496	goto fail;
	497	}
	498
	499	log_warning("LLMNR-IPv6(TCP): There appears to be another LLMNR responder running, or previously systemd-resolved crashed with some outstanding transfers.");
	500
	501	/* try again with SO_REUSEADDR */
	502	r = setsockopt(m->llmnr_ipv6_tcp_fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
	503	if (r < 0) {
	504	r = log_error_errno(errno, "LLMNR-IPv6(TCP): Failed to set SO_REUSEADDR: %m");
	505	goto fail;
	506	}
	507
	508	r = bind(m->llmnr_ipv6_tcp_fd, &sa.sa, sizeof(sa.in6));
	509	if (r < 0) {
	510	r = log_error_errno(errno, "LLMNR-IPv6(TCP): Failed to bind socket: %m");
	511	goto fail;
	512	}
	513	} else {
	514	/* enable SO_REUSEADDR for the case that the user really wants multiple LLMNR responders */
	515	r = setsockopt(m->llmnr_ipv6_tcp_fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
	516	if (r < 0) {
	517	r = log_error_errno(errno, "LLMNR-IPv6(TCP): Failed to set SO_REUSEADDR: %m");
	518	goto fail;
	519	}
5f402ae8 DM	520	}
	521
	522	r = listen(m->llmnr_ipv6_tcp_fd, SOMAXCONN);
	523	if (r < 0) {
007ef0a2	524	r = log_error_errno(errno, "LLMNR-IPv6(TCP): Failed to listen the stream: %m");
5f402ae8 DM	525	goto fail;
	526	}
	527
	528	r = sd_event_add_io(m->event, &m->llmnr_ipv6_tcp_event_source, m->llmnr_ipv6_tcp_fd, EPOLLIN, on_llmnr_stream, m);
ee8d9305	529	if (r < 0)
5f402ae8	530	goto fail;
5f402ae8	531
aa4a9deb LP	532	(void) sd_event_source_set_description(m->llmnr_ipv6_tcp_event_source, "llmnr-ipv6-tcp");
aa4a9deb LP	533
5f402ae8 DM	534	return m->llmnr_ipv6_tcp_fd;
	535
	536	fail:
	537	m->llmnr_ipv6_tcp_fd = safe_close(m->llmnr_ipv6_tcp_fd);
	538	return r;
	539	}