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

/* SPDX-License-Identifier: LGPL-2.1+ */

#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),
        };
        _cleanup_close_ int s = -1;
        int r;

        assert(m);

        if (m->llmnr_ipv4_udp_fd >= 0)
                return m->llmnr_ipv4_udp_fd;

        s = socket(AF_INET, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
        if (s < 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_int(s, IPPROTO_IP, IP_TTL, 255);
        if (r < 0)
                return log_error_errno(r, "LLMNR-IPv4(UDP): Failed to set IP_TTL: %m");

        r = setsockopt_int(s, IPPROTO_IP, IP_MULTICAST_TTL, 255);
        if (r < 0)
                return log_error_errno(r, "LLMNR-IPv4(UDP): Failed to set IP_MULTICAST_TTL: %m");

        r = setsockopt_int(s, IPPROTO_IP, IP_MULTICAST_LOOP, true);
        if (r < 0)
                return log_error_errno(r, "LLMNR-IPv4(UDP): Failed to set IP_MULTICAST_LOOP: %m");

        r = setsockopt_int(s, IPPROTO_IP, IP_PKTINFO, true);
        if (r < 0)
                return log_error_errno(r, "LLMNR-IPv4(UDP): Failed to set IP_PKTINFO: %m");

        r = setsockopt_int(s, IPPROTO_IP, IP_RECVTTL, true);
        if (r < 0)
                return log_error_errno(r, "LLMNR-IPv4(UDP): Failed to set IP_RECVTTL: %m");

        /* Disable Don't-Fragment bit in the IP header */
        r = setsockopt_int(s, IPPROTO_IP, IP_MTU_DISCOVER, IP_PMTUDISC_DONT);
        if (r < 0)
                return log_error_errno(r, "LLMNR-IPv4(UDP): Failed to set IP_MTU_DISCOVER: %m");

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

                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_int(s, SOL_SOCKET, SO_REUSEADDR, true);
                if (r < 0)
                        return log_error_errno(r, "LLMNR-IPv4(UDP): Failed to set SO_REUSEADDR: %m");

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

        r = sd_event_add_io(m->event, &m->llmnr_ipv4_udp_event_source, s, EPOLLIN, on_llmnr_packet, m);
        if (r < 0)
                return log_error_errno(r, "LLMNR-IPv4(UDP): Failed to create event source: %m");

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

        return m->llmnr_ipv4_udp_fd = TAKE_FD(s);
}

int manager_llmnr_ipv6_udp_fd(Manager *m) {
        union sockaddr_union sa = {
                .in6.sin6_family = AF_INET6,
                .in6.sin6_port = htobe16(LLMNR_PORT),
        };
        _cleanup_close_ int s = -1;
        int r;

        assert(m);

        if (m->llmnr_ipv6_udp_fd >= 0)
                return m->llmnr_ipv6_udp_fd;

        s = socket(AF_INET6, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
        if (s < 0)
                return log_error_errno(errno, "LLMNR-IPv6(UDP): Failed to create socket: %m");

        r = setsockopt_int(s, IPPROTO_IPV6, IPV6_UNICAST_HOPS, 255);
        if (r < 0)
                return log_error_errno(r, "LLMNR-IPv6(UDP): Failed to set IPV6_UNICAST_HOPS: %m");

        /* RFC 4795, section 2.5 recommends setting the TTL of UDP packets to 255. */
        r = setsockopt_int(s, IPPROTO_IPV6, IPV6_MULTICAST_HOPS, 255);
        if (r < 0)
                return log_error_errno(r, "LLMNR-IPv6(UDP): Failed to set IPV6_MULTICAST_HOPS: %m");

        r = setsockopt_int(s, IPPROTO_IPV6, IPV6_MULTICAST_LOOP, true);
        if (r < 0)
                return log_error_errno(r, "LLMNR-IPv6(UDP): Failed to set IPV6_MULTICAST_LOOP: %m");

        r = setsockopt_int(s, IPPROTO_IPV6, IPV6_V6ONLY, true);
        if (r < 0)
                return log_error_errno(r, "LLMNR-IPv6(UDP): Failed to set IPV6_V6ONLY: %m");

        r = setsockopt_int(s, IPPROTO_IPV6, IPV6_RECVPKTINFO, true);
        if (r < 0)
                return log_error_errno(r, "LLMNR-IPv6(UDP): Failed to set IPV6_RECVPKTINFO: %m");

        r = setsockopt_int(s, IPPROTO_IPV6, IPV6_RECVHOPLIMIT, true);
        if (r < 0)
                return log_error_errno(r, "LLMNR-IPv6(UDP): Failed to set IPV6_RECVHOPLIMIT: %m");

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

                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_int(s, SOL_SOCKET, SO_REUSEADDR, true);
                if (r < 0)
                        return log_error_errno(r, "LLMNR-IPv6(UDP): Failed to set SO_REUSEADDR: %m");

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

        r = sd_event_add_io(m->event, &m->llmnr_ipv6_udp_event_source, s, EPOLLIN, on_llmnr_packet, m);
        if (r < 0)
                return log_error_errno(r, "LLMNR-IPv6(UDP): Failed to create event source: %m");

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

        return m->llmnr_ipv6_udp_fd = TAKE_FD(s);
}

static int on_llmnr_stream_packet(DnsStream *s) {
        _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL;
        DnsScope *scope;

        assert(s);

        p = dns_stream_take_read_packet(s);
        assert(p);

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

                dns_scope_process_query(scope, s, p);
        } 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),
        };
        _cleanup_close_ int s = -1;
        int r;

        assert(m);

        if (m->llmnr_ipv4_tcp_fd >= 0)
                return m->llmnr_ipv4_tcp_fd;

        s = socket(AF_INET, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
        if (s < 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_int(s, IPPROTO_IP, IP_TTL, true);
        if (r < 0)
                return log_error_errno(r, "LLMNR-IPv4(TCP): Failed to set IP_TTL: %m");

        r = setsockopt_int(s, IPPROTO_IP, IP_PKTINFO, true);
        if (r < 0)
                return log_error_errno(r, "LLMNR-IPv4(TCP): Failed to set IP_PKTINFO: %m");

        r = setsockopt_int(s, IPPROTO_IP, IP_RECVTTL, true);
        if (r < 0)
                return log_error_errno(r, "LLMNR-IPv4(TCP): Failed to set IP_RECVTTL: %m");

        /* Disable Don't-Fragment bit in the IP header */
        r = setsockopt_int(s, IPPROTO_IP, IP_MTU_DISCOVER, IP_PMTUDISC_DONT);
        if (r < 0)
                return log_error_errno(r, "LLMNR-IPv4(TCP): Failed to set IP_MTU_DISCOVER: %m");

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

                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_int(s, SOL_SOCKET, SO_REUSEADDR, true);
                if (r < 0)
                        return log_error_errno(r, "LLMNR-IPv4(TCP): Failed to set SO_REUSEADDR: %m");

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

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

        r = sd_event_add_io(m->event, &m->llmnr_ipv4_tcp_event_source, s, EPOLLIN, on_llmnr_stream, m);
        if (r < 0)
                return log_error_errno(r, "LLMNR-IPv4(TCP): Failed to create event source: %m");

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

        return m->llmnr_ipv4_tcp_fd = TAKE_FD(s);
}

int manager_llmnr_ipv6_tcp_fd(Manager *m) {
        union sockaddr_union sa = {
                .in6.sin6_family = AF_INET6,
                .in6.sin6_port = htobe16(LLMNR_PORT),
        };
        _cleanup_close_ int s = -1;
        int r;

        assert(m);

        if (m->llmnr_ipv6_tcp_fd >= 0)
                return m->llmnr_ipv6_tcp_fd;

        s = socket(AF_INET6, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
        if (s < 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_int(s, IPPROTO_IPV6, IPV6_UNICAST_HOPS, true);
        if (r < 0)
                return log_error_errno(r, "LLMNR-IPv6(TCP): Failed to set IPV6_UNICAST_HOPS: %m");

        r = setsockopt_int(s, IPPROTO_IPV6, IPV6_V6ONLY, true);
        if (r < 0)
                return log_error_errno(r, "LLMNR-IPv6(TCP): Failed to set IPV6_V6ONLY: %m");

        r = setsockopt_int(s, IPPROTO_IPV6, IPV6_RECVPKTINFO, true);
        if (r < 0)
                return log_error_errno(r, "LLMNR-IPv6(TCP): Failed to set IPV6_RECVPKTINFO: %m");

        r = setsockopt_int(s, IPPROTO_IPV6, IPV6_RECVHOPLIMIT, true);
        if (r < 0)
                return log_error_errno(r, "LLMNR-IPv6(TCP): Failed to set IPV6_RECVHOPLIMIT: %m");

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

                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_int(s, SOL_SOCKET, SO_REUSEADDR, true);
                if (r < 0)
                        return log_error_errno(r, "LLMNR-IPv6(TCP): Failed to set SO_REUSEADDR: %m");

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

        r = listen(s, SOMAXCONN);
        if (r < 0)
                return log_error_errno(errno, "LLMNR-IPv6(TCP): Failed to listen the stream: %m");

        r = sd_event_add_io(m->event, &m->llmnr_ipv6_tcp_event_source, s, EPOLLIN, on_llmnr_stream, m);
        if (r < 0)
                return log_error_errno(r, "LLMNR-IPv6(TCP): Failed to create event source: %m");

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

        return m->llmnr_ipv6_tcp_fd = TAKE_FD(s);
}
Commit	Line	Data
53e1b683	1	/* SPDX-License-Identifier: LGPL-2.1+ */
5f402ae8	2
5f402ae8	3	#include <netinet/in.h>
cf0fbc49	4	#include <resolv.h>
5f402ae8	5
3ffd4af2	6	#include "fd-util.h"
5f402ae8	7	#include "resolved-llmnr.h"
3ffd4af2	8	#include "resolved-manager.h"
5f402ae8 DM	9
	10	void manager_llmnr_stop(Manager *m) {
	11	assert(m);
	12
	13	m->llmnr_ipv4_udp_event_source = sd_event_source_unref(m->llmnr_ipv4_udp_event_source);
	14	m->llmnr_ipv4_udp_fd = safe_close(m->llmnr_ipv4_udp_fd);
	15
	16	m->llmnr_ipv6_udp_event_source = sd_event_source_unref(m->llmnr_ipv6_udp_event_source);
	17	m->llmnr_ipv6_udp_fd = safe_close(m->llmnr_ipv6_udp_fd);
	18
	19	m->llmnr_ipv4_tcp_event_source = sd_event_source_unref(m->llmnr_ipv4_tcp_event_source);
	20	m->llmnr_ipv4_tcp_fd = safe_close(m->llmnr_ipv4_tcp_fd);
	21
	22	m->llmnr_ipv6_tcp_event_source = sd_event_source_unref(m->llmnr_ipv6_tcp_event_source);
	23	m->llmnr_ipv6_tcp_fd = safe_close(m->llmnr_ipv6_tcp_fd);
	24	}
	25
	26	int manager_llmnr_start(Manager *m) {
	27	int r;
	28
	29	assert(m);
	30
af49ca27	31	if (m->llmnr_support == RESOLVE_SUPPORT_NO)
5f402ae8 DM	32	return 0;
	33
	34	r = manager_llmnr_ipv4_udp_fd(m);
	35	if (r == -EADDRINUSE)
	36	goto eaddrinuse;
	37	if (r < 0)
	38	return r;
	39
	40	r = manager_llmnr_ipv4_tcp_fd(m);
	41	if (r == -EADDRINUSE)
	42	goto eaddrinuse;
	43	if (r < 0)
	44	return r;
	45
	46	if (socket_ipv6_is_supported()) {
	47	r = manager_llmnr_ipv6_udp_fd(m);
	48	if (r == -EADDRINUSE)
	49	goto eaddrinuse;
	50	if (r < 0)
	51	return r;
	52
	53	r = manager_llmnr_ipv6_tcp_fd(m);
	54	if (r == -EADDRINUSE)
	55	goto eaddrinuse;
	56	if (r < 0)
	57	return r;
	58	}
	59
	60	return 0;
	61
	62	eaddrinuse:
007ef0a2	63	log_warning("Another LLMNR responder prohibits binding the socket to the same port. Turning off LLMNR support.");
af49ca27	64	m->llmnr_support = RESOLVE_SUPPORT_NO;
5f402ae8 DM	65	manager_llmnr_stop(m);
	66
	67	return 0;
	68	}
	69
	70	static int on_llmnr_packet(sd_event_source s, int fd, uint32_t revents, void userdata) {
	71	_cleanup_(dns_packet_unrefp) DnsPacket *p = NULL;
	72	DnsTransaction *t = NULL;
	73	Manager *m = userdata;
	74	DnsScope *scope;
	75	int r;
	76
b30bf55d LP	77	assert(s);
	78	assert(fd >= 0);
	79	assert(m);
	80
5f402ae8 DM	81	r = manager_recv(m, fd, DNS_PROTOCOL_LLMNR, &p);
	82	if (r <= 0)
	83	return r;
	84
6cae1ebe LP	85	if (manager_our_packet(m, p))
	86	return 0;
	87
5f402ae8	88	scope = manager_find_scope(m, p);
f1b1a5c4 LP	89	if (!scope) {
	90	log_debug("Got LLMNR UDP packet on unknown scope. Ignoring.");
	91	return 0;
	92	}
	93
	94	if (dns_packet_validate_reply(p) > 0) {
b30bf55d	95	log_debug("Got LLMNR UDP reply packet for id %u", DNS_PACKET_ID(p));
5f402ae8 DM	96
	97	dns_scope_check_conflicts(scope, p);
	98
	99	t = hashmap_get(m->dns_transactions, UINT_TO_PTR(DNS_PACKET_ID(p)));
	100	if (t)
	101	dns_transaction_process_reply(t, p);
	102
	103	} else if (dns_packet_validate_query(p) > 0) {
b30bf55d	104	log_debug("Got LLMNR UDP query packet for id %u", DNS_PACKET_ID(p));
5f402ae8 DM	105
	106	dns_scope_process_query(scope, NULL, p);
	107	} else
2c6bf498	108	log_debug("Invalid LLMNR UDP packet, ignoring.");
5f402ae8 DM	109
	110	return 0;
	111	}
	112
	113	int manager_llmnr_ipv4_udp_fd(Manager *m) {
	114	union sockaddr_union sa = {
	115	.in.sin_family = AF_INET,
22a37591	116	.in.sin_port = htobe16(LLMNR_PORT),
5f402ae8	117	};
3f548fff	118	_cleanup_close_ int s = -1;
5f402ae8 DM	119	int r;
	120
	121	assert(m);
	122
	123	if (m->llmnr_ipv4_udp_fd >= 0)
	124	return m->llmnr_ipv4_udp_fd;
	125
3f548fff YW	126	s = socket(AF_INET, SOCK_DGRAM\|SOCK_CLOEXEC\|SOCK_NONBLOCK, 0);
3f548fff YW	127	if (s < 0)
007ef0a2	128	return log_error_errno(errno, "LLMNR-IPv4(UDP): Failed to create socket: %m");
5f402ae8 DM	129
5f402ae8 DM	130	/* RFC 4795, section 2.5 recommends setting the TTL of UDP packets to 255. */
3f548fff YW	131	r = setsockopt_int(s, IPPROTO_IP, IP_TTL, 255);
	132	if (r < 0)
	133	return log_error_errno(r, "LLMNR-IPv4(UDP): Failed to set IP_TTL: %m");
5f402ae8	134
3f548fff YW	135	r = setsockopt_int(s, IPPROTO_IP, IP_MULTICAST_TTL, 255);
	136	if (r < 0)
	137	return log_error_errno(r, "LLMNR-IPv4(UDP): Failed to set IP_MULTICAST_TTL: %m");
5f402ae8	138
3f548fff YW	139	r = setsockopt_int(s, IPPROTO_IP, IP_MULTICAST_LOOP, true);
	140	if (r < 0)
	141	return log_error_errno(r, "LLMNR-IPv4(UDP): Failed to set IP_MULTICAST_LOOP: %m");
5f402ae8	142
3f548fff YW	143	r = setsockopt_int(s, IPPROTO_IP, IP_PKTINFO, true);
	144	if (r < 0)
	145	return log_error_errno(r, "LLMNR-IPv4(UDP): Failed to set IP_PKTINFO: %m");
5f402ae8	146
3f548fff YW	147	r = setsockopt_int(s, IPPROTO_IP, IP_RECVTTL, true);
	148	if (r < 0)
	149	return log_error_errno(r, "LLMNR-IPv4(UDP): Failed to set IP_RECVTTL: %m");
5f402ae8 DM	150
5f402ae8 DM	151	/* Disable Don't-Fragment bit in the IP header */
3f548fff YW	152	r = setsockopt_int(s, IPPROTO_IP, IP_MTU_DISCOVER, IP_PMTUDISC_DONT);
	153	if (r < 0)
	154	return log_error_errno(r, "LLMNR-IPv4(UDP): Failed to set IP_MTU_DISCOVER: %m");
5f402ae8	155
007ef0a2	156	/* first try to bind without SO_REUSEADDR to detect another LLMNR responder */
3f548fff	157	r = bind(s, &sa.sa, sizeof(sa.in));
5f402ae8	158	if (r < 0) {
3f548fff YW	159	if (errno != EADDRINUSE)
3f548fff YW	160	return log_error_errno(errno, "LLMNR-IPv4(UDP): Failed to bind socket: %m");
007ef0a2 YW	161
	162	log_warning("LLMNR-IPv4(UDP): There appears to be another LLMNR responder running, or previously systemd-resolved crashed with some outstanding transfers.");
	163
	164	/* try again with SO_REUSEADDR */
3f548fff YW	165	r = setsockopt_int(s, SOL_SOCKET, SO_REUSEADDR, true);
	166	if (r < 0)
	167	return log_error_errno(r, "LLMNR-IPv4(UDP): Failed to set SO_REUSEADDR: %m");
	168
	169	r = bind(s, &sa.sa, sizeof(sa.in));
	170	if (r < 0)
	171	return log_error_errno(errno, "LLMNR-IPv4(UDP): Failed to bind socket: %m");
007ef0a2 YW	172	} else {
007ef0a2 YW	173	/* enable SO_REUSEADDR for the case that the user really wants multiple LLMNR responders */
3f548fff YW	174	r = setsockopt_int(s, SOL_SOCKET, SO_REUSEADDR, true);
	175	if (r < 0)
	176	return log_error_errno(r, "LLMNR-IPv4(UDP): Failed to set SO_REUSEADDR: %m");
5f402ae8 DM	177	}
5f402ae8 DM	178
3f548fff	179	r = sd_event_add_io(m->event, &m->llmnr_ipv4_udp_event_source, s, EPOLLIN, on_llmnr_packet, m);
5f402ae8	180	if (r < 0)
3f548fff	181	return log_error_errno(r, "LLMNR-IPv4(UDP): Failed to create event source: %m");
5f402ae8	182
aa4a9deb LP	183	(void) sd_event_source_set_description(m->llmnr_ipv4_udp_event_source, "llmnr-ipv4-udp");
aa4a9deb LP	184
3f548fff	185	return m->llmnr_ipv4_udp_fd = TAKE_FD(s);
5f402ae8 DM	186	}
	187
	188	int manager_llmnr_ipv6_udp_fd(Manager *m) {
	189	union sockaddr_union sa = {
	190	.in6.sin6_family = AF_INET6,
22a37591	191	.in6.sin6_port = htobe16(LLMNR_PORT),
5f402ae8	192	};
3f548fff	193	_cleanup_close_ int s = -1;
5f402ae8 DM	194	int r;
	195
	196	assert(m);
	197
	198	if (m->llmnr_ipv6_udp_fd >= 0)
	199	return m->llmnr_ipv6_udp_fd;
	200
3f548fff YW	201	s = socket(AF_INET6, SOCK_DGRAM\|SOCK_CLOEXEC\|SOCK_NONBLOCK, 0);
3f548fff YW	202	if (s < 0)
007ef0a2	203	return log_error_errno(errno, "LLMNR-IPv6(UDP): Failed to create socket: %m");
5f402ae8	204
3f548fff YW	205	r = setsockopt_int(s, IPPROTO_IPV6, IPV6_UNICAST_HOPS, 255);
	206	if (r < 0)
	207	return log_error_errno(r, "LLMNR-IPv6(UDP): Failed to set IPV6_UNICAST_HOPS: %m");
5f402ae8 DM	208
5f402ae8 DM	209	/* RFC 4795, section 2.5 recommends setting the TTL of UDP packets to 255. */
3f548fff YW	210	r = setsockopt_int(s, IPPROTO_IPV6, IPV6_MULTICAST_HOPS, 255);
	211	if (r < 0)
	212	return log_error_errno(r, "LLMNR-IPv6(UDP): Failed to set IPV6_MULTICAST_HOPS: %m");
5f402ae8	213
3f548fff YW	214	r = setsockopt_int(s, IPPROTO_IPV6, IPV6_MULTICAST_LOOP, true);
	215	if (r < 0)
	216	return log_error_errno(r, "LLMNR-IPv6(UDP): Failed to set IPV6_MULTICAST_LOOP: %m");
5f402ae8	217
3f548fff YW	218	r = setsockopt_int(s, IPPROTO_IPV6, IPV6_V6ONLY, true);
	219	if (r < 0)
	220	return log_error_errno(r, "LLMNR-IPv6(UDP): Failed to set IPV6_V6ONLY: %m");
5f402ae8	221
3f548fff YW	222	r = setsockopt_int(s, IPPROTO_IPV6, IPV6_RECVPKTINFO, true);
	223	if (r < 0)
	224	return log_error_errno(r, "LLMNR-IPv6(UDP): Failed to set IPV6_RECVPKTINFO: %m");
5f402ae8	225
3f548fff YW	226	r = setsockopt_int(s, IPPROTO_IPV6, IPV6_RECVHOPLIMIT, true);
	227	if (r < 0)
	228	return log_error_errno(r, "LLMNR-IPv6(UDP): Failed to set IPV6_RECVHOPLIMIT: %m");
5f402ae8	229
007ef0a2	230	/* first try to bind without SO_REUSEADDR to detect another LLMNR responder */
3f548fff	231	r = bind(s, &sa.sa, sizeof(sa.in6));
5f402ae8	232	if (r < 0) {
3f548fff YW	233	if (errno != EADDRINUSE)
3f548fff YW	234	return log_error_errno(errno, "LLMNR-IPv6(UDP): Failed to bind socket: %m");
007ef0a2 YW	235
	236	log_warning("LLMNR-IPv6(UDP): There appears to be another LLMNR responder running, or previously systemd-resolved crashed with some outstanding transfers.");
	237
	238	/* try again with SO_REUSEADDR */
3f548fff YW	239	r = setsockopt_int(s, SOL_SOCKET, SO_REUSEADDR, true);
	240	if (r < 0)
	241	return log_error_errno(r, "LLMNR-IPv6(UDP): Failed to set SO_REUSEADDR: %m");
	242
	243	r = bind(s, &sa.sa, sizeof(sa.in6));
	244	if (r < 0)
	245	return log_error_errno(errno, "LLMNR-IPv6(UDP): Failed to bind socket: %m");
007ef0a2 YW	246	} else {
007ef0a2 YW	247	/* enable SO_REUSEADDR for the case that the user really wants multiple LLMNR responders */
3f548fff YW	248	r = setsockopt_int(s, SOL_SOCKET, SO_REUSEADDR, true);
	249	if (r < 0)
	250	return log_error_errno(r, "LLMNR-IPv6(UDP): Failed to set SO_REUSEADDR: %m");
5f402ae8 DM	251	}
5f402ae8 DM	252
3f548fff	253	r = sd_event_add_io(m->event, &m->llmnr_ipv6_udp_event_source, s, EPOLLIN, on_llmnr_packet, m);
35908b98	254	if (r < 0)
3f548fff	255	return log_error_errno(r, "LLMNR-IPv6(UDP): Failed to create event source: %m");
5f402ae8	256
aa4a9deb LP	257	(void) sd_event_source_set_description(m->llmnr_ipv6_udp_event_source, "llmnr-ipv6-udp");
aa4a9deb LP	258
3f548fff	259	return m->llmnr_ipv6_udp_fd = TAKE_FD(s);
5f402ae8 DM	260	}
	261
	262	static int on_llmnr_stream_packet(DnsStream *s) {
aa337a5e	263	_cleanup_(dns_packet_unrefp) DnsPacket *p = NULL;
5f402ae8 DM	264	DnsScope *scope;
	265
	266	assert(s);
	267
aa337a5e LP	268	p = dns_stream_take_read_packet(s);
	269	assert(p);
	270
	271	scope = manager_find_scope(s->manager, p);
b30bf55d	272	if (!scope)
f1b1a5c4	273	log_debug("Got LLMNR TCP packet on unknown scope. Ignoring.");
aa337a5e LP	274	else if (dns_packet_validate_query(p) > 0) {
aa337a5e LP	275	log_debug("Got LLMNR TCP query packet for id %u", DNS_PACKET_ID(p));
5f402ae8	276
aa337a5e	277	dns_scope_process_query(scope, s, p);
5f402ae8	278	} else
b30bf55d	279	log_debug("Invalid LLMNR TCP packet, ignoring.");
5f402ae8	280
b30bf55d	281	dns_stream_unref(s);
5f402ae8 DM	282	return 0;
	283	}
	284
	285	static int on_llmnr_stream(sd_event_source s, int fd, uint32_t revents, void userdata) {
	286	DnsStream *stream;
	287	Manager *m = userdata;
	288	int cfd, r;
	289
	290	cfd = accept4(fd, NULL, NULL, SOCK_NONBLOCK\|SOCK_CLOEXEC);
	291	if (cfd < 0) {
3742095b	292	if (IN_SET(errno, EAGAIN, EINTR))
5f402ae8 DM	293	return 0;
	294
	295	return -errno;
	296	}
	297
91ccab1e	298	r = dns_stream_new(m, &stream, DNS_PROTOCOL_LLMNR, cfd, NULL);
5f402ae8 DM	299	if (r < 0) {
	300	safe_close(cfd);
	301	return r;
	302	}
	303
	304	stream->on_packet = on_llmnr_stream_packet;
	305	return 0;
	306	}
	307
	308	int manager_llmnr_ipv4_tcp_fd(Manager *m) {
	309	union sockaddr_union sa = {
	310	.in.sin_family = AF_INET,
22a37591	311	.in.sin_port = htobe16(LLMNR_PORT),
5f402ae8	312	};
3f548fff	313	_cleanup_close_ int s = -1;
5f402ae8 DM	314	int r;
	315
	316	assert(m);
	317
	318	if (m->llmnr_ipv4_tcp_fd >= 0)
	319	return m->llmnr_ipv4_tcp_fd;
	320
3f548fff YW	321	s = socket(AF_INET, SOCK_STREAM\|SOCK_CLOEXEC\|SOCK_NONBLOCK, 0);
3f548fff YW	322	if (s < 0)
007ef0a2	323	return log_error_errno(errno, "LLMNR-IPv4(TCP): Failed to create socket: %m");
5f402ae8 DM	324
5f402ae8 DM	325	/* RFC 4795, section 2.5. requires setting the TTL of TCP streams to 1 */
3f548fff YW	326	r = setsockopt_int(s, IPPROTO_IP, IP_TTL, true);
	327	if (r < 0)
	328	return log_error_errno(r, "LLMNR-IPv4(TCP): Failed to set IP_TTL: %m");
5f402ae8	329
3f548fff YW	330	r = setsockopt_int(s, IPPROTO_IP, IP_PKTINFO, true);
	331	if (r < 0)
	332	return log_error_errno(r, "LLMNR-IPv4(TCP): Failed to set IP_PKTINFO: %m");
5f402ae8	333
3f548fff YW	334	r = setsockopt_int(s, IPPROTO_IP, IP_RECVTTL, true);
	335	if (r < 0)
	336	return log_error_errno(r, "LLMNR-IPv4(TCP): Failed to set IP_RECVTTL: %m");
5f402ae8 DM	337
5f402ae8 DM	338	/* Disable Don't-Fragment bit in the IP header */
3f548fff YW	339	r = setsockopt_int(s, IPPROTO_IP, IP_MTU_DISCOVER, IP_PMTUDISC_DONT);
	340	if (r < 0)
	341	return log_error_errno(r, "LLMNR-IPv4(TCP): Failed to set IP_MTU_DISCOVER: %m");
5f402ae8	342
007ef0a2	343	/* first try to bind without SO_REUSEADDR to detect another LLMNR responder */
3f548fff	344	r = bind(s, &sa.sa, sizeof(sa.in));
5f402ae8	345	if (r < 0) {
3f548fff YW	346	if (errno != EADDRINUSE)
3f548fff YW	347	return log_error_errno(errno, "LLMNR-IPv4(TCP): Failed to bind socket: %m");
007ef0a2 YW	348
	349	log_warning("LLMNR-IPv4(TCP): There appears to be another LLMNR responder running, or previously systemd-resolved crashed with some outstanding transfers.");
	350
	351	/* try again with SO_REUSEADDR */
3f548fff YW	352	r = setsockopt_int(s, SOL_SOCKET, SO_REUSEADDR, true);
	353	if (r < 0)
	354	return log_error_errno(r, "LLMNR-IPv4(TCP): Failed to set SO_REUSEADDR: %m");
	355
	356	r = bind(s, &sa.sa, sizeof(sa.in));
	357	if (r < 0)
	358	return log_error_errno(errno, "LLMNR-IPv4(TCP): Failed to bind socket: %m");
007ef0a2 YW	359	} else {
007ef0a2 YW	360	/* enable SO_REUSEADDR for the case that the user really wants multiple LLMNR responders */
3f548fff YW	361	r = setsockopt_int(s, SOL_SOCKET, SO_REUSEADDR, true);
	362	if (r < 0)
	363	return log_error_errno(r, "LLMNR-IPv4(TCP): Failed to set SO_REUSEADDR: %m");
5f402ae8 DM	364	}
5f402ae8 DM	365
3f548fff YW	366	r = listen(s, SOMAXCONN);
	367	if (r < 0)
	368	return log_error_errno(errno, "LLMNR-IPv4(TCP): Failed to listen the stream: %m");
5f402ae8	369
3f548fff	370	r = sd_event_add_io(m->event, &m->llmnr_ipv4_tcp_event_source, s, EPOLLIN, on_llmnr_stream, m);
5f402ae8	371	if (r < 0)
3f548fff	372	return log_error_errno(r, "LLMNR-IPv4(TCP): Failed to create event source: %m");
5f402ae8	373
aa4a9deb LP	374	(void) sd_event_source_set_description(m->llmnr_ipv4_tcp_event_source, "llmnr-ipv4-tcp");
aa4a9deb LP	375
3f548fff	376	return m->llmnr_ipv4_tcp_fd = TAKE_FD(s);
5f402ae8 DM	377	}
	378
	379	int manager_llmnr_ipv6_tcp_fd(Manager *m) {
	380	union sockaddr_union sa = {
	381	.in6.sin6_family = AF_INET6,
22a37591	382	.in6.sin6_port = htobe16(LLMNR_PORT),
5f402ae8	383	};
3f548fff	384	_cleanup_close_ int s = -1;
5f402ae8 DM	385	int r;
	386
	387	assert(m);
	388
	389	if (m->llmnr_ipv6_tcp_fd >= 0)
	390	return m->llmnr_ipv6_tcp_fd;
	391
3f548fff YW	392	s = socket(AF_INET6, SOCK_STREAM\|SOCK_CLOEXEC\|SOCK_NONBLOCK, 0);
3f548fff YW	393	if (s < 0)
007ef0a2	394	return log_error_errno(errno, "LLMNR-IPv6(TCP): Failed to create socket: %m");
5f402ae8 DM	395
5f402ae8 DM	396	/* RFC 4795, section 2.5. requires setting the TTL of TCP streams to 1 */
3f548fff YW	397	r = setsockopt_int(s, IPPROTO_IPV6, IPV6_UNICAST_HOPS, true);
	398	if (r < 0)
	399	return log_error_errno(r, "LLMNR-IPv6(TCP): Failed to set IPV6_UNICAST_HOPS: %m");
5f402ae8	400
3f548fff YW	401	r = setsockopt_int(s, IPPROTO_IPV6, IPV6_V6ONLY, true);
	402	if (r < 0)
	403	return log_error_errno(r, "LLMNR-IPv6(TCP): Failed to set IPV6_V6ONLY: %m");
5f402ae8	404
3f548fff YW	405	r = setsockopt_int(s, IPPROTO_IPV6, IPV6_RECVPKTINFO, true);
	406	if (r < 0)
	407	return log_error_errno(r, "LLMNR-IPv6(TCP): Failed to set IPV6_RECVPKTINFO: %m");
5f402ae8	408
3f548fff YW	409	r = setsockopt_int(s, IPPROTO_IPV6, IPV6_RECVHOPLIMIT, true);
	410	if (r < 0)
	411	return log_error_errno(r, "LLMNR-IPv6(TCP): Failed to set IPV6_RECVHOPLIMIT: %m");
5f402ae8	412
007ef0a2	413	/* first try to bind without SO_REUSEADDR to detect another LLMNR responder */
3f548fff	414	r = bind(s, &sa.sa, sizeof(sa.in6));
5f402ae8	415	if (r < 0) {
3f548fff YW	416	if (errno != EADDRINUSE)
3f548fff YW	417	return log_error_errno(errno, "LLMNR-IPv6(TCP): Failed to bind socket: %m");
007ef0a2 YW	418
	419	log_warning("LLMNR-IPv6(TCP): There appears to be another LLMNR responder running, or previously systemd-resolved crashed with some outstanding transfers.");
	420
	421	/* try again with SO_REUSEADDR */
3f548fff YW	422	r = setsockopt_int(s, SOL_SOCKET, SO_REUSEADDR, true);
	423	if (r < 0)
	424	return log_error_errno(r, "LLMNR-IPv6(TCP): Failed to set SO_REUSEADDR: %m");
	425
	426	r = bind(s, &sa.sa, sizeof(sa.in6));
	427	if (r < 0)
	428	return log_error_errno(errno, "LLMNR-IPv6(TCP): Failed to bind socket: %m");
007ef0a2 YW	429	} else {
007ef0a2 YW	430	/* enable SO_REUSEADDR for the case that the user really wants multiple LLMNR responders */
3f548fff YW	431	r = setsockopt_int(s, SOL_SOCKET, SO_REUSEADDR, true);
	432	if (r < 0)
	433	return log_error_errno(r, "LLMNR-IPv6(TCP): Failed to set SO_REUSEADDR: %m");
5f402ae8 DM	434	}
5f402ae8 DM	435
3f548fff YW	436	r = listen(s, SOMAXCONN);
	437	if (r < 0)
	438	return log_error_errno(errno, "LLMNR-IPv6(TCP): Failed to listen the stream: %m");
5f402ae8	439
3f548fff	440	r = sd_event_add_io(m->event, &m->llmnr_ipv6_tcp_event_source, s, EPOLLIN, on_llmnr_stream, m);
ee8d9305	441	if (r < 0)
3f548fff	442	return log_error_errno(r, "LLMNR-IPv6(TCP): Failed to create event source: %m");
5f402ae8	443
aa4a9deb LP	444	(void) sd_event_source_set_description(m->llmnr_ipv6_tcp_event_source, "llmnr-ipv6-tcp");
aa4a9deb LP	445
3f548fff	446	return m->llmnr_ipv6_tcp_fd = TAKE_FD(s);
5f402ae8	447	}