resolved: move LLMNR related functions into separate file

1 files changed, 473 insertions, 0 deletions

diff --git a/src/resolve/resolved-llmnr.c b/src/resolve/resolved-llmnr.c
new file mode 100644
index 0000000000..ee9a416372
--- /dev/null
+++ b/src/resolve/resolved-llmnr.c
@@ -0,0 +1,473 @@
+/*-*- 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(5355),
+        };
+        static const int one = 1, pmtu = IP_PMTUDISC_DONT, ttl = 255;
+        int r;
+
+        assert(m);
+
+        if (m->llmnr_ipv4_udp_fd >= 0)
+                return m->llmnr_ipv4_udp_fd;
+
+        m->llmnr_ipv4_udp_fd = socket(AF_INET, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
+        if (m->llmnr_ipv4_udp_fd < 0)
+                return -errno;
+
+        /* RFC 4795, section 2.5 recommends setting the TTL of UDP packets to 255. */
+        r = setsockopt(m->llmnr_ipv4_udp_fd, IPPROTO_IP, IP_TTL, &ttl, sizeof(ttl));
+        if (r < 0) {
+                r = -errno;
+                goto fail;
+        }
+
+        r = setsockopt(m->llmnr_ipv4_udp_fd, IPPROTO_IP, IP_MULTICAST_TTL, &ttl, sizeof(ttl));
+        if (r < 0) {
+                r = -errno;
+                goto fail;
+        }
+
+        r = setsockopt(m->llmnr_ipv4_udp_fd, IPPROTO_IP, IP_MULTICAST_LOOP, &one, sizeof(one));
+        if (r < 0) {
+                r = -errno;
+                goto fail;
+        }
+
+        r = setsockopt(m->llmnr_ipv4_udp_fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
+        if (r < 0) {
+                r = -errno;
+                goto fail;
+        }
+
+        r = setsockopt(m->llmnr_ipv4_udp_fd, IPPROTO_IP, IP_PKTINFO, &one, sizeof(one));
+        if (r < 0) {
+                r = -errno;
+                goto fail;
+        }
+
+        r = setsockopt(m->llmnr_ipv4_udp_fd, IPPROTO_IP, IP_RECVTTL, &one, sizeof(one));
+        if (r < 0) {
+                r = -errno;
+                goto fail;
+        }
+
+        /* Disable Don't-Fragment bit in the IP header */
+        r = setsockopt(m->llmnr_ipv4_udp_fd, IPPROTO_IP, IP_MTU_DISCOVER, &pmtu, sizeof(pmtu));
+        if (r < 0) {
+                r = -errno;
+                goto fail;
+        }
+
+        r = bind(m->llmnr_ipv4_udp_fd, &sa.sa, sizeof(sa.in));
+        if (r < 0) {
+                r = -errno;
+                goto fail;
+        }
+
+        r = sd_event_add_io(m->event, &m->llmnr_ipv4_udp_event_source, m->llmnr_ipv4_udp_fd, EPOLLIN, on_llmnr_packet, m);
+        if (r < 0)
+                goto fail;
+
+        return m->llmnr_ipv4_udp_fd;
+
+fail:
+        m->llmnr_ipv4_udp_fd = safe_close(m->llmnr_ipv4_udp_fd);
+        return r;
+}
+
+int manager_llmnr_ipv6_udp_fd(Manager *m) {
+        union sockaddr_union sa = {
+                .in6.sin6_family = AF_INET6,
+                .in6.sin6_port = htobe16(5355),
+        };
+        static const int one = 1, ttl = 255;
+        int r;
+
+        assert(m);
+
+        if (m->llmnr_ipv6_udp_fd >= 0)
+                return m->llmnr_ipv6_udp_fd;
+
+        m->llmnr_ipv6_udp_fd = socket(AF_INET6, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
+        if (m->llmnr_ipv6_udp_fd < 0)
+                return -errno;
+
+        r = setsockopt(m->llmnr_ipv6_udp_fd, IPPROTO_IPV6, IPV6_UNICAST_HOPS, &ttl, sizeof(ttl));
+        if (r < 0) {
+                r = -errno;
+                goto fail;
+        }
+
+        /* RFC 4795, section 2.5 recommends setting the TTL of UDP packets to 255. */
+        r = setsockopt(m->llmnr_ipv6_udp_fd, IPPROTO_IPV6, IPV6_MULTICAST_HOPS, &ttl, sizeof(ttl));
+        if (r < 0) {
+                r = -errno;
+                goto fail;
+        }
+
+        r = setsockopt(m->llmnr_ipv6_udp_fd, IPPROTO_IPV6, IPV6_MULTICAST_LOOP, &one, sizeof(one));
+        if (r < 0) {
+                r = -errno;
+                goto fail;
+        }
+
+        r = setsockopt(m->llmnr_ipv6_udp_fd, IPPROTO_IPV6, IPV6_V6ONLY, &one, sizeof(one));
+        if (r < 0) {
+                r = -errno;
+                goto fail;
+        }
+
+        r = setsockopt(m->llmnr_ipv6_udp_fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
+        if (r < 0) {
+                r = -errno;
+                goto fail;
+        }
+
+        r = setsockopt(m->llmnr_ipv6_udp_fd, IPPROTO_IPV6, IPV6_RECVPKTINFO, &one, sizeof(one));
+        if (r < 0) {
+                r = -errno;
+                goto fail;
+        }
+
+        r = setsockopt(m->llmnr_ipv6_udp_fd, IPPROTO_IPV6, IPV6_RECVHOPLIMIT, &one, sizeof(one));
+        if (r < 0) {
+                r = -errno;
+                goto fail;
+        }
+
+        r = bind(m->llmnr_ipv6_udp_fd, &sa.sa, sizeof(sa.in6));
+        if (r < 0) {
+                r = -errno;
+                goto fail;
+        }
+
+        r = sd_event_add_io(m->event, &m->llmnr_ipv6_udp_event_source, m->llmnr_ipv6_udp_fd, EPOLLIN, on_llmnr_packet, m);
+        if (r < 0)  {
+                r = -errno;
+                goto fail;
+        }
+
+        return m->llmnr_ipv6_udp_fd;
+
+fail:
+        m->llmnr_ipv6_udp_fd = safe_close(m->llmnr_ipv6_udp_fd);
+        return r;
+}
+
+static int on_llmnr_stream_packet(DnsStream *s) {
+        DnsScope *scope;
+
+        assert(s);
+
+        scope = manager_find_scope(s->manager, s->read_packet);
+        if (!scope) {
+                log_warning("Got LLMNR TCP packet on unknown scope. Ignroing.");
+                return 0;
+        }
+
+        if (dns_packet_validate_query(s->read_packet) > 0) {
+                log_debug("Got query packet for id %u", DNS_PACKET_ID(s->read_packet));
+
+                dns_scope_process_query(scope, s, s->read_packet);
+
+                /* If no reply packet was set, we free the stream */
+                if (s->write_packet)
+                        return 0;
+        } else
+                log_debug("Invalid LLMNR TCP packet.");
+
+        dns_stream_free(s);
+        return 0;
+}
+
+static int on_llmnr_stream(sd_event_source *s, int fd, uint32_t revents, void *userdata) {
+        DnsStream *stream;
+        Manager *m = userdata;
+        int cfd, r;
+
+        cfd = accept4(fd, NULL, NULL, SOCK_NONBLOCK|SOCK_CLOEXEC);
+        if (cfd < 0) {
+                if (errno == EAGAIN || errno == EINTR)
+                        return 0;
+
+                return -errno;
+        }
+
+        r = dns_stream_new(m, &stream, DNS_PROTOCOL_LLMNR, cfd);
+        if (r < 0) {
+                safe_close(cfd);
+                return r;
+        }
+
+        stream->on_packet = on_llmnr_stream_packet;
+        return 0;
+}
+
+int manager_llmnr_ipv4_tcp_fd(Manager *m) {
+        union sockaddr_union sa = {
+                .in.sin_family = AF_INET,
+                .in.sin_port = htobe16(5355),
+        };
+        static const int one = 1, pmtu = IP_PMTUDISC_DONT;
+        int r;
+
+        assert(m);
+
+        if (m->llmnr_ipv4_tcp_fd >= 0)
+                return m->llmnr_ipv4_tcp_fd;
+
+        m->llmnr_ipv4_tcp_fd = socket(AF_INET, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
+        if (m->llmnr_ipv4_tcp_fd < 0)
+                return -errno;
+
+        /* RFC 4795, section 2.5. requires setting the TTL of TCP streams to 1 */
+        r = setsockopt(m->llmnr_ipv4_tcp_fd, IPPROTO_IP, IP_TTL, &one, sizeof(one));
+        if (r < 0) {
+                r = -errno;
+                goto fail;
+        }
+
+        r = setsockopt(m->llmnr_ipv4_tcp_fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
+        if (r < 0) {
+                r = -errno;
+                goto fail;
+        }
+
+        r = setsockopt(m->llmnr_ipv4_tcp_fd, IPPROTO_IP, IP_PKTINFO, &one, sizeof(one));
+        if (r < 0) {
+                r = -errno;
+                goto fail;
+        }
+
+        r = setsockopt(m->llmnr_ipv4_tcp_fd, IPPROTO_IP, IP_RECVTTL, &one, sizeof(one));
+        if (r < 0) {
+                r = -errno;
+                goto fail;
+        }
+
+        /* Disable Don't-Fragment bit in the IP header */
+        r = setsockopt(m->llmnr_ipv4_tcp_fd, IPPROTO_IP, IP_MTU_DISCOVER, &pmtu, sizeof(pmtu));
+        if (r < 0) {
+                r = -errno;
+                goto fail;
+        }
+
+        r = bind(m->llmnr_ipv4_tcp_fd, &sa.sa, sizeof(sa.in));
+        if (r < 0) {
+                r = -errno;
+                goto fail;
+        }
+
+        r = listen(m->llmnr_ipv4_tcp_fd, SOMAXCONN);
+        if (r < 0) {
+                r = -errno;
+                goto fail;
+        }
+
+        r = sd_event_add_io(m->event, &m->llmnr_ipv4_tcp_event_source, m->llmnr_ipv4_tcp_fd, EPOLLIN, on_llmnr_stream, m);
+        if (r < 0)
+                goto fail;
+
+        return m->llmnr_ipv4_tcp_fd;
+
+fail:
+        m->llmnr_ipv4_tcp_fd = safe_close(m->llmnr_ipv4_tcp_fd);
+        return r;
+}
+
+int manager_llmnr_ipv6_tcp_fd(Manager *m) {
+        union sockaddr_union sa = {
+                .in6.sin6_family = AF_INET6,
+                .in6.sin6_port = htobe16(5355),
+        };
+        static const int one = 1;
+        int r;
+
+        assert(m);
+
+        if (m->llmnr_ipv6_tcp_fd >= 0)
+                return m->llmnr_ipv6_tcp_fd;
+
+        m->llmnr_ipv6_tcp_fd = socket(AF_INET6, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
+        if (m->llmnr_ipv6_tcp_fd < 0)
+                return -errno;
+
+        /* RFC 4795, section 2.5. requires setting the TTL of TCP streams to 1 */
+        r = setsockopt(m->llmnr_ipv6_tcp_fd, IPPROTO_IPV6, IPV6_UNICAST_HOPS, &one, sizeof(one));
+        if (r < 0) {
+                r = -errno;
+                goto fail;
+        }
+
+        r = setsockopt(m->llmnr_ipv6_tcp_fd, IPPROTO_IPV6, IPV6_V6ONLY, &one, sizeof(one));
+        if (r < 0) {
+                r = -errno;
+                goto fail;
+        }
+
+        r = setsockopt(m->llmnr_ipv6_tcp_fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
+        if (r < 0) {
+                r = -errno;
+                goto fail;
+        }
+
+        r = setsockopt(m->llmnr_ipv6_tcp_fd, IPPROTO_IPV6, IPV6_RECVPKTINFO, &one, sizeof(one));
+        if (r < 0) {
+                r = -errno;
+                goto fail;
+        }
+
+        r = setsockopt(m->llmnr_ipv6_tcp_fd, IPPROTO_IPV6, IPV6_RECVHOPLIMIT, &one, sizeof(one));
+        if (r < 0) {
+                r = -errno;
+                goto fail;
+        }
+
+        r = bind(m->llmnr_ipv6_tcp_fd, &sa.sa, sizeof(sa.in6));
+        if (r < 0) {
+                r = -errno;
+                goto fail;
+        }
+
+        r = listen(m->llmnr_ipv6_tcp_fd, SOMAXCONN);
+        if (r < 0) {
+                r = -errno;
+                goto fail;
+        }
+
+        r = sd_event_add_io(m->event, &m->llmnr_ipv6_tcp_event_source, m->llmnr_ipv6_tcp_fd, EPOLLIN, on_llmnr_stream, m);
+        if (r < 0)  {
+                r = -errno;
+                goto fail;
+        }
+
+        return m->llmnr_ipv6_tcp_fd;
+
+fail:
+        m->llmnr_ipv6_tcp_fd = safe_close(m->llmnr_ipv6_tcp_fd);
+        return r;
+}