| /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ |
| |
| /*** |
| 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 <resolv.h> |
| #include <netinet/in.h> |
| |
| #include "resolved-manager.h" |
| #include "resolved-llmnr.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 == 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("There appears to be another LLMNR responder running. Turning off LLMNR support."); |
| m->llmnr_support = 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; |
| |
| r = manager_recv(m, fd, DNS_PROTOCOL_LLMNR, &p); |
| if (r <= 0) |
| return r; |
| |
| scope = manager_find_scope(m, p); |
| if (!scope) { |
| log_warning("Got LLMNR UDP packet on unknown scope. Ignoring."); |
| return 0; |
| } |
| |
| if (dns_packet_validate_reply(p) > 0) { |
| log_debug("Got LLMNR 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 query packet for id %u", DNS_PACKET_ID(p)); |
| |
| dns_scope_process_query(scope, NULL, p); |
| } else |
| log_debug("Invalid LLMNR UDP packet."); |
| |
| return 0; |
| } |
| |
| int manager_llmnr_ipv4_udp_fd(Manager *m) { |
| union sockaddr_union sa = { |
| .in.sin_family = AF_INET, |
| .in.sin_port = htobe16(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 -errno; |
| |
| /* RFC 4795, section 2.5 recommends setting the TTL of UDP packets to 255. */ |
| r = setsockopt(m->llmnr_ipv4_udp_fd, IPPROTO_IP, IP_TTL, &ttl, sizeof(ttl)); |
| if (r < 0) { |
| r = -errno; |
| goto fail; |
| } |
| |
| r = setsockopt(m->llmnr_ipv4_udp_fd, IPPROTO_IP, IP_MULTICAST_TTL, &ttl, sizeof(ttl)); |
| if (r < 0) { |
| r = -errno; |
| goto fail; |
| } |
| |
| r = setsockopt(m->llmnr_ipv4_udp_fd, IPPROTO_IP, IP_MULTICAST_LOOP, &one, sizeof(one)); |
| if (r < 0) { |
| r = -errno; |
| goto fail; |
| } |
| |
| r = setsockopt(m->llmnr_ipv4_udp_fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one)); |
| if (r < 0) { |
| r = -errno; |
| goto fail; |
| } |
| |
| r = setsockopt(m->llmnr_ipv4_udp_fd, IPPROTO_IP, IP_PKTINFO, &one, sizeof(one)); |
| if (r < 0) { |
| r = -errno; |
| goto fail; |
| } |
| |
| r = setsockopt(m->llmnr_ipv4_udp_fd, IPPROTO_IP, IP_RECVTTL, &one, sizeof(one)); |
| if (r < 0) { |
| r = -errno; |
| goto fail; |
| } |
| |
| /* Disable Don't-Fragment bit in the IP header */ |
| r = setsockopt(m->llmnr_ipv4_udp_fd, IPPROTO_IP, IP_MTU_DISCOVER, &pmtu, sizeof(pmtu)); |
| if (r < 0) { |
| r = -errno; |
| goto fail; |
| } |
| |
| r = bind(m->llmnr_ipv4_udp_fd, &sa.sa, sizeof(sa.in)); |
| if (r < 0) { |
| r = -errno; |
| goto fail; |
| } |
| |
| r = sd_event_add_io(m->event, &m->llmnr_ipv4_udp_event_source, m->llmnr_ipv4_udp_fd, EPOLLIN, on_llmnr_packet, m); |
| if (r < 0) |
| goto fail; |
| |
| return m->llmnr_ipv4_udp_fd; |
| |
| fail: |
| m->llmnr_ipv4_udp_fd = safe_close(m->llmnr_ipv4_udp_fd); |
| return r; |
| } |
| |
| int manager_llmnr_ipv6_udp_fd(Manager *m) { |
| union sockaddr_union sa = { |
| .in6.sin6_family = AF_INET6, |
| .in6.sin6_port = htobe16(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 -errno; |
| |
| r = setsockopt(m->llmnr_ipv6_udp_fd, IPPROTO_IPV6, IPV6_UNICAST_HOPS, &ttl, sizeof(ttl)); |
| if (r < 0) { |
| r = -errno; |
| goto fail; |
| } |
| |
| /* RFC 4795, section 2.5 recommends setting the TTL of UDP packets to 255. */ |
| r = setsockopt(m->llmnr_ipv6_udp_fd, IPPROTO_IPV6, IPV6_MULTICAST_HOPS, &ttl, sizeof(ttl)); |
| if (r < 0) { |
| r = -errno; |
| goto fail; |
| } |
| |
| r = setsockopt(m->llmnr_ipv6_udp_fd, IPPROTO_IPV6, IPV6_MULTICAST_LOOP, &one, sizeof(one)); |
| if (r < 0) { |
| r = -errno; |
| goto fail; |
| } |
| |
| r = setsockopt(m->llmnr_ipv6_udp_fd, IPPROTO_IPV6, IPV6_V6ONLY, &one, sizeof(one)); |
| if (r < 0) { |
| r = -errno; |
| goto fail; |
| } |
| |
| r = setsockopt(m->llmnr_ipv6_udp_fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one)); |
| if (r < 0) { |
| r = -errno; |
| goto fail; |
| } |
| |
| r = setsockopt(m->llmnr_ipv6_udp_fd, IPPROTO_IPV6, IPV6_RECVPKTINFO, &one, sizeof(one)); |
| if (r < 0) { |
| r = -errno; |
| goto fail; |
| } |
| |
| r = setsockopt(m->llmnr_ipv6_udp_fd, IPPROTO_IPV6, IPV6_RECVHOPLIMIT, &one, sizeof(one)); |
| if (r < 0) { |
| r = -errno; |
| goto fail; |
| } |
| |
| r = bind(m->llmnr_ipv6_udp_fd, &sa.sa, sizeof(sa.in6)); |
| if (r < 0) { |
| r = -errno; |
| goto fail; |
| } |
| |
| r = sd_event_add_io(m->event, &m->llmnr_ipv6_udp_event_source, m->llmnr_ipv6_udp_fd, EPOLLIN, on_llmnr_packet, m); |
| if (r < 0) { |
| r = -errno; |
| goto fail; |
| } |
| |
| return m->llmnr_ipv6_udp_fd; |
| |
| fail: |
| m->llmnr_ipv6_udp_fd = safe_close(m->llmnr_ipv6_udp_fd); |
| return r; |
| } |
| |
| static int on_llmnr_stream_packet(DnsStream *s) { |
| DnsScope *scope; |
| |
| assert(s); |
| |
| scope = manager_find_scope(s->manager, s->read_packet); |
| if (!scope) { |
| log_warning("Got LLMNR TCP packet on unknown scope. Ignroing."); |
| return 0; |
| } |
| |
| if (dns_packet_validate_query(s->read_packet) > 0) { |
| log_debug("Got query packet for id %u", DNS_PACKET_ID(s->read_packet)); |
| |
| dns_scope_process_query(scope, s, s->read_packet); |
| |
| /* If no reply packet was set, we free the stream */ |
| if (s->write_packet) |
| return 0; |
| } else |
| log_debug("Invalid LLMNR TCP packet."); |
| |
| dns_stream_free(s); |
| return 0; |
| } |
| |
| static int on_llmnr_stream(sd_event_source *s, int fd, uint32_t revents, void *userdata) { |
| DnsStream *stream; |
| Manager *m = userdata; |
| int cfd, r; |
| |
| cfd = accept4(fd, NULL, NULL, SOCK_NONBLOCK|SOCK_CLOEXEC); |
| if (cfd < 0) { |
| if (errno == EAGAIN || errno == EINTR) |
| return 0; |
| |
| return -errno; |
| } |
| |
| r = dns_stream_new(m, &stream, DNS_PROTOCOL_LLMNR, cfd); |
| if (r < 0) { |
| safe_close(cfd); |
| return r; |
| } |
| |
| stream->on_packet = on_llmnr_stream_packet; |
| return 0; |
| } |
| |
| int manager_llmnr_ipv4_tcp_fd(Manager *m) { |
| union sockaddr_union sa = { |
| .in.sin_family = AF_INET, |
| .in.sin_port = htobe16(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 -errno; |
| |
| /* RFC 4795, section 2.5. requires setting the TTL of TCP streams to 1 */ |
| r = setsockopt(m->llmnr_ipv4_tcp_fd, IPPROTO_IP, IP_TTL, &one, sizeof(one)); |
| if (r < 0) { |
| r = -errno; |
| goto fail; |
| } |
| |
| r = setsockopt(m->llmnr_ipv4_tcp_fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one)); |
| if (r < 0) { |
| r = -errno; |
| goto fail; |
| } |
| |
| r = setsockopt(m->llmnr_ipv4_tcp_fd, IPPROTO_IP, IP_PKTINFO, &one, sizeof(one)); |
| if (r < 0) { |
| r = -errno; |
| goto fail; |
| } |
| |
| r = setsockopt(m->llmnr_ipv4_tcp_fd, IPPROTO_IP, IP_RECVTTL, &one, sizeof(one)); |
| if (r < 0) { |
| r = -errno; |
| goto fail; |
| } |
| |
| /* Disable Don't-Fragment bit in the IP header */ |
| r = setsockopt(m->llmnr_ipv4_tcp_fd, IPPROTO_IP, IP_MTU_DISCOVER, &pmtu, sizeof(pmtu)); |
| if (r < 0) { |
| r = -errno; |
| goto fail; |
| } |
| |
| r = bind(m->llmnr_ipv4_tcp_fd, &sa.sa, sizeof(sa.in)); |
| if (r < 0) { |
| r = -errno; |
| goto fail; |
| } |
| |
| r = listen(m->llmnr_ipv4_tcp_fd, SOMAXCONN); |
| if (r < 0) { |
| r = -errno; |
| goto fail; |
| } |
| |
| r = sd_event_add_io(m->event, &m->llmnr_ipv4_tcp_event_source, m->llmnr_ipv4_tcp_fd, EPOLLIN, on_llmnr_stream, m); |
| if (r < 0) |
| goto fail; |
| |
| return m->llmnr_ipv4_tcp_fd; |
| |
| fail: |
| m->llmnr_ipv4_tcp_fd = safe_close(m->llmnr_ipv4_tcp_fd); |
| return r; |
| } |
| |
| int manager_llmnr_ipv6_tcp_fd(Manager *m) { |
| union sockaddr_union sa = { |
| .in6.sin6_family = AF_INET6, |
| .in6.sin6_port = htobe16(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 -errno; |
| |
| /* RFC 4795, section 2.5. requires setting the TTL of TCP streams to 1 */ |
| r = setsockopt(m->llmnr_ipv6_tcp_fd, IPPROTO_IPV6, IPV6_UNICAST_HOPS, &one, sizeof(one)); |
| if (r < 0) { |
| r = -errno; |
| goto fail; |
| } |
| |
| r = setsockopt(m->llmnr_ipv6_tcp_fd, IPPROTO_IPV6, IPV6_V6ONLY, &one, sizeof(one)); |
| if (r < 0) { |
| r = -errno; |
| goto fail; |
| } |
| |
| r = setsockopt(m->llmnr_ipv6_tcp_fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one)); |
| if (r < 0) { |
| r = -errno; |
| goto fail; |
| } |
| |
| r = setsockopt(m->llmnr_ipv6_tcp_fd, IPPROTO_IPV6, IPV6_RECVPKTINFO, &one, sizeof(one)); |
| if (r < 0) { |
| r = -errno; |
| goto fail; |
| } |
| |
| r = setsockopt(m->llmnr_ipv6_tcp_fd, IPPROTO_IPV6, IPV6_RECVHOPLIMIT, &one, sizeof(one)); |
| if (r < 0) { |
| r = -errno; |
| goto fail; |
| } |
| |
| r = bind(m->llmnr_ipv6_tcp_fd, &sa.sa, sizeof(sa.in6)); |
| if (r < 0) { |
| r = -errno; |
| goto fail; |
| } |
| |
| r = listen(m->llmnr_ipv6_tcp_fd, SOMAXCONN); |
| if (r < 0) { |
| r = -errno; |
| goto fail; |
| } |
| |
| r = sd_event_add_io(m->event, &m->llmnr_ipv6_tcp_event_source, m->llmnr_ipv6_tcp_fd, EPOLLIN, on_llmnr_stream, m); |
| if (r < 0) { |
| r = -errno; |
| goto fail; |
| } |
| |
| return m->llmnr_ipv6_tcp_fd; |
| |
| fail: |
| m->llmnr_ipv6_tcp_fd = safe_close(m->llmnr_ipv6_tcp_fd); |
| return r; |
| } |