-/***
- This file is part of systemd.
-
- Copyright 2015 Daniel Mack
-
- 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/>.
- ***/
+/* SPDX-License-Identifier: LGPL-2.1+ */
#include <resolv.h>
#include <netinet/in.h>
#include <arpa/inet.h>
+#include "alloc-util.h"
#include "fd-util.h"
#include "resolved-manager.h"
#include "resolved-mdns.h"
+#include "sort-util.h"
+
+#define CLEAR_CACHE_FLUSH(x) (~MDNS_RR_CACHE_FLUSH & (x))
void manager_mdns_stop(Manager *m) {
assert(m);
return 0;
}
+static int mdns_rr_compare(DnsResourceRecord * const *a, DnsResourceRecord * const *b) {
+ DnsResourceRecord *x = *(DnsResourceRecord **) a, *y = *(DnsResourceRecord **) b;
+ size_t m;
+ int r;
+
+ assert(x);
+ assert(y);
+
+ r = CMP(CLEAR_CACHE_FLUSH(x->key->class), CLEAR_CACHE_FLUSH(y->key->class));
+ if (r != 0)
+ return r;
+
+ r = CMP(x->key->type, y->key->type);
+ if (r != 0)
+ return r;
+
+ r = dns_resource_record_to_wire_format(x, false);
+ if (r < 0) {
+ log_warning_errno(r, "Can't wire-format RR: %m");
+ return 0;
+ }
+
+ r = dns_resource_record_to_wire_format(y, false);
+ if (r < 0) {
+ log_warning_errno(r, "Can't wire-format RR: %m");
+ return 0;
+ }
+
+ m = MIN(DNS_RESOURCE_RECORD_RDATA_SIZE(x), DNS_RESOURCE_RECORD_RDATA_SIZE(y));
+
+ r = memcmp(DNS_RESOURCE_RECORD_RDATA(x), DNS_RESOURCE_RECORD_RDATA(y), m);
+ if (r != 0)
+ return r;
+
+ return CMP(DNS_RESOURCE_RECORD_RDATA_SIZE(x), DNS_RESOURCE_RECORD_RDATA_SIZE(y));
+}
+
+static int proposed_rrs_cmp(DnsResourceRecord **x, unsigned x_size, DnsResourceRecord **y, unsigned y_size) {
+ unsigned m;
+ int r;
+
+ m = MIN(x_size, y_size);
+ for (unsigned i = 0; i < m; i++) {
+ r = mdns_rr_compare(&x[i], &y[i]);
+ if (r != 0)
+ return r;
+ }
+
+ return CMP(x_size, y_size);
+}
+
+static int mdns_packet_extract_matching_rrs(DnsPacket *p, DnsResourceKey *key, DnsResourceRecord ***ret_rrs) {
+ _cleanup_free_ DnsResourceRecord **list = NULL;
+ unsigned n = 0, size = 0;
+ int r;
+
+ assert(p);
+ assert(key);
+ assert(ret_rrs);
+ assert_return(DNS_PACKET_NSCOUNT(p) > 0, -EINVAL);
+
+ for (size_t i = DNS_PACKET_ANCOUNT(p); i < (DNS_PACKET_ANCOUNT(p) + DNS_PACKET_NSCOUNT(p)); i++) {
+ r = dns_resource_key_match_rr(key, p->answer->items[i].rr, NULL);
+ if (r < 0)
+ return r;
+ if (r > 0)
+ size++;
+ }
+
+ if (size == 0)
+ return 0;
+
+ list = new(DnsResourceRecord *, size);
+ if (!list)
+ return -ENOMEM;
+
+ for (size_t i = DNS_PACKET_ANCOUNT(p); i < (DNS_PACKET_ANCOUNT(p) + DNS_PACKET_NSCOUNT(p)); i++) {
+ r = dns_resource_key_match_rr(key, p->answer->items[i].rr, NULL);
+ if (r < 0)
+ return r;
+ if (r > 0)
+ list[n++] = p->answer->items[i].rr;
+ }
+ assert(n == size);
+ typesafe_qsort(list, size, mdns_rr_compare);
+
+ *ret_rrs = TAKE_PTR(list);
+
+ return size;
+}
+
+static int mdns_do_tiebreak(DnsResourceKey *key, DnsAnswer *answer, DnsPacket *p) {
+ _cleanup_free_ DnsResourceRecord **our = NULL, **remote = NULL;
+ DnsResourceRecord *rr;
+ size_t i = 0, size;
+ int r;
+
+ size = dns_answer_size(answer);
+ our = new(DnsResourceRecord *, size);
+ if (!our)
+ return -ENOMEM;
+
+ DNS_ANSWER_FOREACH(rr, answer)
+ our[i++] = rr;
+
+ typesafe_qsort(our, size, mdns_rr_compare);
+
+ r = mdns_packet_extract_matching_rrs(p, key, &remote);
+ if (r < 0)
+ return r;
+
+ assert(r > 0);
+
+ if (proposed_rrs_cmp(remote, r, our, size) > 0)
+ return 1;
+
+ return 0;
+}
+
static int mdns_scope_process_query(DnsScope *s, DnsPacket *p) {
- _cleanup_(dns_answer_unrefp) DnsAnswer *answer = NULL, *soa = NULL;
+ _cleanup_(dns_answer_unrefp) DnsAnswer *full_answer = NULL;
_cleanup_(dns_packet_unrefp) DnsPacket *reply = NULL;
DnsResourceKey *key = NULL;
+ DnsResourceRecord *rr;
bool tentative = false;
int r;
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) {
- log_debug_errno(r, "Failed to lookup key: %m");
- return r;
+ DNS_QUESTION_FOREACH(key, p->question) {
+ _cleanup_(dns_answer_unrefp) DnsAnswer *answer = NULL, *soa = NULL;
+
+ 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 (tentative && DNS_PACKET_NSCOUNT(p) > 0) {
+ /*
+ * A race condition detected with the probe packet from
+ * a remote host.
+ * Do simultaneous probe tiebreaking as described in
+ * RFC 6762, Section 8.2. In case we lost don't reply
+ * the question and withdraw conflicting RRs.
+ */
+ r = mdns_do_tiebreak(key, answer, p);
+ if (r < 0)
+ return log_debug_errno(r, "Failed to do tiebreaking");
+
+ if (r > 0) { /* we lost */
+ DNS_ANSWER_FOREACH(rr, answer) {
+ DnsZoneItem *i;
+
+ i = dns_zone_get(&s->zone, rr);
+ if (i)
+ dns_zone_item_conflict(i);
+ }
+
+ continue;
+ }
+ }
+
+ r = dns_answer_extend(&full_answer, answer);
+ if (r < 0)
+ return log_debug_errno(r, "Failed to extend answer: %m");
}
- if (r == 0)
+
+ if (dns_answer_isempty(full_answer))
return 0;
- r = dns_scope_make_reply_packet(s, DNS_PACKET_ID(p), DNS_RCODE_SUCCESS, NULL, answer, NULL, false, &reply);
- if (r < 0) {
- log_debug_errno(r, "Failed to build reply packet: %m");
- return r;
- }
+ r = dns_scope_make_reply_packet(s, DNS_PACKET_ID(p), DNS_RCODE_SUCCESS, NULL, full_answer, NULL, false, &reply);
+ if (r < 0)
+ return log_debug_errno(r, "Failed to build reply packet: %m");
- if (!ratelimit_test(&s->ratelimit))
+ if (!ratelimit_below(&s->ratelimit))
return 0;
r = dns_scope_emit_udp(s, -1, reply);
- if (r < 0) {
- log_debug_errno(r, "Failed to send reply packet: %m");
- return r;
- }
+ if (r < 0)
+ return log_debug_errno(r, "Failed to send reply packet: %m");
return 0;
}
scope = manager_find_scope(m, p);
if (!scope) {
- log_warning("Got mDNS UDP packet on unknown scope. Ignoring.");
+ log_debug("Got mDNS UDP packet on unknown scope. Ignoring.");
return 0;
}
.in.sin_family = AF_INET,
.in.sin_port = htobe16(MDNS_PORT),
};
- static const int one = 1, pmtu = IP_PMTUDISC_DONT, ttl = 255;
+ _cleanup_close_ int s = -1;
int r;
assert(m);
if (m->mdns_ipv4_fd >= 0)
return m->mdns_ipv4_fd;
- m->mdns_ipv4_fd = socket(AF_INET, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
- if (m->mdns_ipv4_fd < 0)
+ s = socket(AF_INET, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
+ if (s < 0)
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 = log_error_errno(errno, "mDNS-IPv4: Failed to set IP_TTL: %m");
- goto fail;
- }
+ r = setsockopt_int(s, IPPROTO_IP, IP_TTL, 255);
+ if (r < 0)
+ return log_error_errno(r, "mDNS-IPv4: Failed to set IP_TTL: %m");
- r = setsockopt(m->mdns_ipv4_fd, IPPROTO_IP, IP_MULTICAST_TTL, &ttl, sizeof(ttl));
- if (r < 0) {
- r = log_error_errno(errno, "mDNS-IPv4: Failed to set IP_MULTICAST_TTL: %m");
- goto fail;
- }
+ r = setsockopt_int(s, IPPROTO_IP, IP_MULTICAST_TTL, 255);
+ if (r < 0)
+ return log_error_errno(r, "mDNS-IPv4: Failed to set IP_MULTICAST_TTL: %m");
- r = setsockopt(m->mdns_ipv4_fd, IPPROTO_IP, IP_MULTICAST_LOOP, &one, sizeof(one));
- if (r < 0) {
- r = log_error_errno(errno, "mDNS-IPv4: Failed to set IP_MULTICAST_LOOP: %m");
- goto fail;
- }
+ r = setsockopt_int(s, IPPROTO_IP, IP_MULTICAST_LOOP, true);
+ if (r < 0)
+ return log_error_errno(r, "mDNS-IPv4: Failed to set IP_MULTICAST_LOOP: %m");
- r = setsockopt(m->mdns_ipv4_fd, IPPROTO_IP, IP_PKTINFO, &one, sizeof(one));
- if (r < 0) {
- r = log_error_errno(errno, "mDNS-IPv4: Failed to set IP_PKTINFO: %m");
- goto fail;
- }
+ r = setsockopt_int(s, IPPROTO_IP, IP_PKTINFO, true);
+ if (r < 0)
+ return log_error_errno(r, "mDNS-IPv4: Failed to set IP_PKTINFO: %m");
- r = setsockopt(m->mdns_ipv4_fd, IPPROTO_IP, IP_RECVTTL, &one, sizeof(one));
- if (r < 0) {
- r = log_error_errno(errno, "mDNS-IPv4: Failed to set IP_RECVTTL: %m");
- goto fail;
- }
+ r = setsockopt_int(s, IPPROTO_IP, IP_RECVTTL, true);
+ if (r < 0)
+ return log_error_errno(r, "mDNS-IPv4: Failed to set IP_RECVTTL: %m");
/* 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 = log_error_errno(errno, "mDNS-IPv4: Failed to set IP_MTU_DISCOVER: %m");
- goto fail;
- }
+ r = setsockopt_int(s, IPPROTO_IP, IP_MTU_DISCOVER, IP_PMTUDISC_DONT);
+ if (r < 0)
+ return log_error_errno(r, "mDNS-IPv4: Failed to set IP_MTU_DISCOVER: %m");
/* 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));
+ r = bind(s, &sa.sa, sizeof(sa.in));
if (r < 0) {
- if (errno != EADDRINUSE) {
- r = log_error_errno(errno, "mDNS-IPv4: Failed to bind socket: %m");
- goto fail;
- }
+ if (errno != EADDRINUSE)
+ return log_error_errno(errno, "mDNS-IPv4: Failed to bind socket: %m");
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 = setsockopt_int(s, SOL_SOCKET, SO_REUSEADDR, true);
+ if (r < 0)
+ return log_error_errno(r, "mDNS-IPv4: Failed to set SO_REUSEADDR: %m");
- 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;
- }
+ r = bind(s, &sa.sa, sizeof(sa.in));
+ if (r < 0)
+ return log_error_errno(errno, "mDNS-IPv4: Failed to bind socket: %m");
} 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 = setsockopt_int(s, SOL_SOCKET, SO_REUSEADDR, true);
+ if (r < 0)
+ return log_error_errno(r, "mDNS-IPv4: Failed to set SO_REUSEADDR: %m");
}
- r = sd_event_add_io(m->event, &m->mdns_ipv4_event_source, m->mdns_ipv4_fd, EPOLLIN, on_mdns_packet, m);
+ r = sd_event_add_io(m->event, &m->mdns_ipv4_event_source, s, EPOLLIN, on_mdns_packet, m);
if (r < 0)
- goto fail;
+ return log_error_errno(r, "mDNS-IPv4: Failed to create event source: %m");
- return m->mdns_ipv4_fd;
-
-fail:
- m->mdns_ipv4_fd = safe_close(m->mdns_ipv4_fd);
- return r;
+ return m->mdns_ipv4_fd = TAKE_FD(s);
}
int manager_mdns_ipv6_fd(Manager *m) {
.in6.sin6_family = AF_INET6,
.in6.sin6_port = htobe16(MDNS_PORT),
};
- static const int one = 1, ttl = 255;
+ _cleanup_close_ int s = -1;
int r;
assert(m);
if (m->mdns_ipv6_fd >= 0)
return m->mdns_ipv6_fd;
- m->mdns_ipv6_fd = socket(AF_INET6, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
- if (m->mdns_ipv6_fd < 0)
+ s = socket(AF_INET6, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
+ if (s < 0)
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 = log_error_errno(errno, "mDNS-IPv6: Failed to set IPV6_UNICAST_HOPS: %m");
- goto fail;
- }
+ r = setsockopt_int(s, IPPROTO_IPV6, IPV6_UNICAST_HOPS, 255);
+ if (r < 0)
+ return log_error_errno(r, "mDNS-IPv6: Failed to set IPV6_UNICAST_HOPS: %m");
/* 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 = log_error_errno(errno, "mDNS-IPv6: Failed to set IPV6_MULTICAST_HOPS: %m");
- goto fail;
- }
+ r = setsockopt_int(s, IPPROTO_IPV6, IPV6_MULTICAST_HOPS, 255);
+ if (r < 0)
+ return log_error_errno(r, "mDNS-IPv6: Failed to set IPV6_MULTICAST_HOPS: %m");
- r = setsockopt(m->mdns_ipv6_fd, IPPROTO_IPV6, IPV6_MULTICAST_LOOP, &one, sizeof(one));
- if (r < 0) {
- r = log_error_errno(errno, "mDNS-IPv6: Failed to set IPV6_MULTICAST_LOOP: %m");
- goto fail;
- }
+ r = setsockopt_int(s, IPPROTO_IPV6, IPV6_MULTICAST_LOOP, true);
+ if (r < 0)
+ return log_error_errno(r, "mDNS-IPv6: Failed to set IPV6_MULTICAST_LOOP: %m");
- r = setsockopt(m->mdns_ipv6_fd, IPPROTO_IPV6, IPV6_V6ONLY, &one, sizeof(one));
- if (r < 0) {
- r = log_error_errno(errno, "mDNS-IPv6: Failed to set IPV6_V6ONLY: %m");
- goto fail;
- }
+ r = setsockopt_int(s, IPPROTO_IPV6, IPV6_V6ONLY, true);
+ if (r < 0)
+ return log_error_errno(r, "mDNS-IPv6: Failed to set IPV6_V6ONLY: %m");
- r = setsockopt(m->mdns_ipv6_fd, IPPROTO_IPV6, IPV6_RECVPKTINFO, &one, sizeof(one));
- if (r < 0) {
- r = log_error_errno(errno, "mDNS-IPv6: Failed to set IPV6_RECVPKTINFO: %m");
- goto fail;
- }
+ r = setsockopt_int(s, IPPROTO_IPV6, IPV6_RECVPKTINFO, true);
+ if (r < 0)
+ return log_error_errno(r, "mDNS-IPv6: Failed to set IPV6_RECVPKTINFO: %m");
- r = setsockopt(m->mdns_ipv6_fd, IPPROTO_IPV6, IPV6_RECVHOPLIMIT, &one, sizeof(one));
- if (r < 0) {
- r = log_error_errno(errno, "mDNS-IPv6: Failed to set IPV6_RECVHOPLIMIT: %m");
- goto fail;
- }
+ r = setsockopt_int(s, IPPROTO_IPV6, IPV6_RECVHOPLIMIT, true);
+ if (r < 0)
+ return log_error_errno(r, "mDNS-IPv6: Failed to set IPV6_RECVHOPLIMIT: %m");
/* 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));
+ r = bind(s, &sa.sa, sizeof(sa.in6));
if (r < 0) {
- if (errno != EADDRINUSE) {
- r = log_error_errno(errno, "mDNS-IPv6: Failed to bind socket: %m");
- goto fail;
- }
+ if (errno != EADDRINUSE)
+ return log_error_errno(errno, "mDNS-IPv6: Failed to bind socket: %m");
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 = setsockopt_int(s, SOL_SOCKET, SO_REUSEADDR, true);
+ if (r < 0)
+ return log_error_errno(r, "mDNS-IPv6: Failed to set SO_REUSEADDR: %m");
- 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;
- }
+ r = bind(s, &sa.sa, sizeof(sa.in6));
+ if (r < 0)
+ return log_error_errno(errno, "mDNS-IPv6: Failed to bind socket: %m");
} 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 = setsockopt_int(s, SOL_SOCKET, SO_REUSEADDR, true);
+ if (r < 0)
+ return log_error_errno(r, "mDNS-IPv6: Failed to set SO_REUSEADDR: %m");
}
- r = sd_event_add_io(m->event, &m->mdns_ipv6_event_source, m->mdns_ipv6_fd, EPOLLIN, on_mdns_packet, m);
+ r = sd_event_add_io(m->event, &m->mdns_ipv6_event_source, s, EPOLLIN, on_mdns_packet, m);
if (r < 0)
- goto fail;
+ return log_error_errno(r, "mDNS-IPv6: Failed to create event source: %m");
- return m->mdns_ipv6_fd;
-
-fail:
- m->mdns_ipv6_fd = safe_close(m->mdns_ipv6_fd);
- return r;
+ return m->mdns_ipv6_fd = TAKE_FD(s);
}
projects / thirdparty / systemd.git / blobdiff