+/* SPDX-License-Identifier: LGPL-2.1+ */
/***
This file is part of systemd.
return 0;
eaddrinuse:
- log_warning("There appears to be another mDNS responder running. Turning off mDNS support.");
+ log_warning("Another mDNS responder prohibits binding the socket to the same port. Turning off mDNS support.");
m->mdns_support = RESOLVE_SUPPORT_NO;
manager_mdns_stop(m);
return 0;
}
+static int mdns_scope_process_query(DnsScope *s, DnsPacket *p) {
+ _cleanup_(dns_answer_unrefp) DnsAnswer *answer = NULL, *soa = NULL;
+ _cleanup_(dns_packet_unrefp) DnsPacket *reply = NULL;
+ DnsResourceKey *key = NULL;
+ bool tentative = false;
+ int r;
+
+ assert(s);
+ assert(p);
+
+ r = dns_packet_extract(p);
+ if (r < 0)
+ return log_debug_errno(r, "Failed to extract resource records from incoming packet: %m");
+
+ /* TODO: there might be more than one question in mDNS queries. */
+ assert_return((dns_question_size(p->question) > 0), -EINVAL);
+ key = p->question->keys[0];
+
+ r = dns_zone_lookup(&s->zone, key, 0, &answer, &soa, &tentative);
+ if (r < 0)
+ return log_debug_errno(r, "Failed to lookup key: %m");
+ if (r == 0)
+ return 0;
+
+ r = dns_scope_make_reply_packet(s, DNS_PACKET_ID(p), DNS_RCODE_SUCCESS, NULL, answer, NULL, false, &reply);
+ if (r < 0)
+ return log_debug_errno(r, "Failed to build reply packet: %m");
+
+ if (!ratelimit_test(&s->ratelimit))
+ return 0;
+
+ r = dns_scope_emit_udp(s, -1, reply);
+ if (r < 0)
+ return log_debug_errno(r, "Failed to send reply packet: %m");
+
+ return 0;
+}
+
static int on_mdns_packet(sd_event_source *s, int fd, uint32_t revents, void *userdata) {
_cleanup_(dns_packet_unrefp) DnsPacket *p = NULL;
Manager *m = userdata;
if (r <= 0)
return r;
+ if (manager_our_packet(m, p))
+ return 0;
+
scope = manager_find_scope(m, p);
if (!scope) {
log_warning("Got mDNS UDP packet on unknown scope. Ignoring.");
dns_name_endswith(name, "local") > 0))
return 0;
+ if (rr->ttl == 0) {
+ log_debug("Got a goodbye packet");
+ /* See the section 10.1 of RFC6762 */
+ rr->ttl = 1;
+ }
+
t = dns_scope_find_transaction(scope, rr->key, false);
if (t)
dns_transaction_process_reply(t, p);
+
+ /* Also look for the various types of ANY transactions */
+ t = dns_scope_find_transaction(scope, &DNS_RESOURCE_KEY_CONST(rr->key->class, DNS_TYPE_ANY, dns_resource_key_name(rr->key)), false);
+ if (t)
+ dns_transaction_process_reply(t, p);
+
+ t = dns_scope_find_transaction(scope, &DNS_RESOURCE_KEY_CONST(DNS_CLASS_ANY, rr->key->type, dns_resource_key_name(rr->key)), false);
+ if (t)
+ dns_transaction_process_reply(t, p);
+
+ t = dns_scope_find_transaction(scope, &DNS_RESOURCE_KEY_CONST(DNS_CLASS_ANY, DNS_TYPE_ANY, dns_resource_key_name(rr->key)), false);
+ if (t)
+ dns_transaction_process_reply(t, p);
}
dns_cache_put(&scope->cache, NULL, DNS_PACKET_RCODE(p), p->answer, false, (uint32_t) -1, 0, p->family, &p->sender);
} else if (dns_packet_validate_query(p) > 0) {
log_debug("Got mDNS query packet for id %u", DNS_PACKET_ID(p));
- dns_scope_process_query(scope, NULL, p);
+ r = mdns_scope_process_query(scope, p);
+ if (r < 0) {
+ log_debug_errno(r, "mDNS query processing failed: %m");
+ return 0;
+ }
} else
log_debug("Invalid mDNS UDP packet.");
m->mdns_ipv4_fd = socket(AF_INET, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
if (m->mdns_ipv4_fd < 0)
- return -errno;
+ return log_error_errno(errno, "mDNS-IPv4: Failed to create socket: %m");
r = setsockopt(m->mdns_ipv4_fd, IPPROTO_IP, IP_TTL, &ttl, sizeof(ttl));
if (r < 0) {
- r = -errno;
+ r = log_error_errno(errno, "mDNS-IPv4: Failed to set IP_TTL: %m");
goto fail;
}
r = setsockopt(m->mdns_ipv4_fd, IPPROTO_IP, IP_MULTICAST_TTL, &ttl, sizeof(ttl));
if (r < 0) {
- r = -errno;
+ r = log_error_errno(errno, "mDNS-IPv4: Failed to set IP_MULTICAST_TTL: %m");
goto fail;
}
r = setsockopt(m->mdns_ipv4_fd, IPPROTO_IP, IP_MULTICAST_LOOP, &one, sizeof(one));
if (r < 0) {
- r = -errno;
- goto fail;
- }
-
- r = setsockopt(m->mdns_ipv4_fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
- if (r < 0) {
- r = -errno;
+ r = log_error_errno(errno, "mDNS-IPv4: Failed to set IP_MULTICAST_LOOP: %m");
goto fail;
}
r = setsockopt(m->mdns_ipv4_fd, IPPROTO_IP, IP_PKTINFO, &one, sizeof(one));
if (r < 0) {
- r = -errno;
+ r = log_error_errno(errno, "mDNS-IPv4: Failed to set IP_PKTINFO: %m");
goto fail;
}
r = setsockopt(m->mdns_ipv4_fd, IPPROTO_IP, IP_RECVTTL, &one, sizeof(one));
if (r < 0) {
- r = -errno;
+ r = log_error_errno(errno, "mDNS-IPv4: Failed to set IP_RECVTTL: %m");
goto fail;
}
/* Disable Don't-Fragment bit in the IP header */
r = setsockopt(m->mdns_ipv4_fd, IPPROTO_IP, IP_MTU_DISCOVER, &pmtu, sizeof(pmtu));
if (r < 0) {
- r = -errno;
+ r = log_error_errno(errno, "mDNS-IPv4: Failed to set IP_MTU_DISCOVER: %m");
goto fail;
}
+ /* See the section 15.1 of RFC6762 */
+ /* first try to bind without SO_REUSEADDR to detect another mDNS responder */
r = bind(m->mdns_ipv4_fd, &sa.sa, sizeof(sa.in));
if (r < 0) {
- r = -errno;
- goto fail;
+ if (errno != EADDRINUSE) {
+ r = log_error_errno(errno, "mDNS-IPv4: Failed to bind socket: %m");
+ goto fail;
+ }
+
+ log_warning("mDNS-IPv4: There appears to be another mDNS responder running, or previously systemd-resolved crashed with some outstanding transfers.");
+
+ /* try again with SO_REUSEADDR */
+ r = setsockopt(m->mdns_ipv4_fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
+ if (r < 0) {
+ r = log_error_errno(errno, "mDNS-IPv4: Failed to set SO_REUSEADDR: %m");
+ goto fail;
+ }
+
+ r = bind(m->mdns_ipv4_fd, &sa.sa, sizeof(sa.in));
+ if (r < 0) {
+ r = log_error_errno(errno, "mDNS-IPv4: Failed to bind socket: %m");
+ goto fail;
+ }
+ } else {
+ /* enable SO_REUSEADDR for the case that the user really wants multiple mDNS responders */
+ r = setsockopt(m->mdns_ipv4_fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
+ if (r < 0) {
+ r = log_error_errno(errno, "mDNS-IPv4: Failed to set SO_REUSEADDR: %m");
+ goto fail;
+ }
}
r = sd_event_add_io(m->event, &m->mdns_ipv4_event_source, m->mdns_ipv4_fd, EPOLLIN, on_mdns_packet, m);
m->mdns_ipv6_fd = socket(AF_INET6, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
if (m->mdns_ipv6_fd < 0)
- return -errno;
+ return log_error_errno(errno, "mDNS-IPv6: Failed to create socket: %m");
r = setsockopt(m->mdns_ipv6_fd, IPPROTO_IPV6, IPV6_UNICAST_HOPS, &ttl, sizeof(ttl));
if (r < 0) {
- r = -errno;
+ r = log_error_errno(errno, "mDNS-IPv6: 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->mdns_ipv6_fd, IPPROTO_IPV6, IPV6_MULTICAST_HOPS, &ttl, sizeof(ttl));
if (r < 0) {
- r = -errno;
+ r = log_error_errno(errno, "mDNS-IPv6: Failed to set IPV6_MULTICAST_HOPS: %m");
goto fail;
}
r = setsockopt(m->mdns_ipv6_fd, IPPROTO_IPV6, IPV6_MULTICAST_LOOP, &one, sizeof(one));
if (r < 0) {
- r = -errno;
+ r = log_error_errno(errno, "mDNS-IPv6: Failed to set IPV6_MULTICAST_LOOP: %m");
goto fail;
}
r = setsockopt(m->mdns_ipv6_fd, IPPROTO_IPV6, IPV6_V6ONLY, &one, sizeof(one));
if (r < 0) {
- r = -errno;
- goto fail;
- }
-
- r = setsockopt(m->mdns_ipv6_fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
- if (r < 0) {
- r = -errno;
+ r = log_error_errno(errno, "mDNS-IPv6: Failed to set IPV6_V6ONLY: %m");
goto fail;
}
r = setsockopt(m->mdns_ipv6_fd, IPPROTO_IPV6, IPV6_RECVPKTINFO, &one, sizeof(one));
if (r < 0) {
- r = -errno;
+ r = log_error_errno(errno, "mDNS-IPv6: Failed to set IPV6_RECVPKTINFO: %m");
goto fail;
}
r = setsockopt(m->mdns_ipv6_fd, IPPROTO_IPV6, IPV6_RECVHOPLIMIT, &one, sizeof(one));
if (r < 0) {
- r = -errno;
+ r = log_error_errno(errno, "mDNS-IPv6: Failed to set IPV6_RECVHOPLIMIT: %m");
goto fail;
}
+ /* See the section 15.1 of RFC6762 */
+ /* first try to bind without SO_REUSEADDR to detect another mDNS responder */
r = bind(m->mdns_ipv6_fd, &sa.sa, sizeof(sa.in6));
if (r < 0) {
- r = -errno;
- goto fail;
+ if (errno != EADDRINUSE) {
+ r = log_error_errno(errno, "mDNS-IPv6: Failed to bind socket: %m");
+ goto fail;
+ }
+
+ log_warning("mDNS-IPv6: There appears to be another mDNS responder running, or previously systemd-resolved crashed with some outstanding transfers.");
+
+ /* try again with SO_REUSEADDR */
+ r = setsockopt(m->mdns_ipv6_fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
+ if (r < 0) {
+ r = log_error_errno(errno, "mDNS-IPv6: Failed to set SO_REUSEADDR: %m");
+ goto fail;
+ }
+
+ r = bind(m->mdns_ipv6_fd, &sa.sa, sizeof(sa.in6));
+ if (r < 0) {
+ r = log_error_errno(errno, "mDNS-IPv6: Failed to bind socket: %m");
+ goto fail;
+ }
+ } else {
+ /* enable SO_REUSEADDR for the case that the user really wants multiple mDNS responders */
+ r = setsockopt(m->mdns_ipv6_fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
+ if (r < 0) {
+ r = log_error_errno(errno, "mDNS-IPv6: Failed to set SO_REUSEADDR: %m");
+ goto fail;
+ }
}
r = sd_event_add_io(m->event, &m->mdns_ipv6_event_source, m->mdns_ipv6_fd, EPOLLIN, on_mdns_packet, m);
projects / thirdparty / systemd.git / blobdiff