#include <netinet/tcp.h>
+#include "missing.h"
#include "strv.h"
#include "socket-util.h"
+#include "af-list.h"
#include "resolved-dns-domain.h"
#include "resolved-dns-scope.h"
-#define SEND_TIMEOUT_USEC (2*USEC_PER_SEC)
+#define MULTICAST_RATELIMIT_INTERVAL_USEC (1*USEC_PER_SEC)
+#define MULTICAST_RATELIMIT_BURST 1000
-int dns_scope_new(Manager *m, DnsScope **ret, DnsScopeType t) {
+int dns_scope_new(Manager *m, DnsScope **ret, Link *l, DnsProtocol protocol, int family) {
DnsScope *s;
assert(m);
return -ENOMEM;
s->manager = m;
- s->type = t;
+ s->link = l;
+ s->protocol = protocol;
+ s->family = family;
LIST_PREPEND(scopes, m->dns_scopes, s);
+ dns_scope_llmnr_membership(s, true);
+
+ log_debug("New scope on link %s, protocol %s, family %s", l ? l->name : "*", dns_protocol_to_string(protocol), family == AF_UNSPEC ? "*" : af_to_name(family));
+
+ /* Enforce ratelimiting for the multicast protocols */
+ RATELIMIT_INIT(s->ratelimit, MULTICAST_RATELIMIT_INTERVAL_USEC, MULTICAST_RATELIMIT_BURST);
+
*ret = s;
return 0;
}
DnsScope* dns_scope_free(DnsScope *s) {
+ DnsTransaction *t;
+ DnsResourceRecord *rr;
+
if (!s)
return NULL;
- while (s->transactions) {
- DnsQuery *q;
+ log_debug("Removing scope on link %s, protocol %s, family %s", s->link ? s->link->name : "*", dns_protocol_to_string(s->protocol), s->family == AF_UNSPEC ? "*" : af_to_name(s->family));
- q = s->transactions->query;
- dns_query_transaction_free(s->transactions);
+ dns_scope_llmnr_membership(s, false);
- dns_query_finish(q);
+ while ((t = s->transactions)) {
+
+ /* Abort the transaction, but make sure it is not
+ * freed while we still look at it */
+
+ t->block_gc++;
+ dns_transaction_complete(t, DNS_TRANSACTION_ABORTED);
+ t->block_gc--;
+
+ dns_transaction_free(t);
}
+ while ((rr = ordered_hashmap_steal_first(s->conflict_queue)))
+ dns_resource_record_unref(rr);
+
+ ordered_hashmap_free(s->conflict_queue);
+ sd_event_source_unref(s->conflict_event_source);
+
+ dns_cache_flush(&s->cache);
+ dns_zone_flush(&s->zone);
+
LIST_REMOVE(scopes, s->manager->dns_scopes, s);
strv_free(s->domains);
free(s);
return NULL;
}
-DnsServer *dns_scope_get_server(DnsScope *s) {
+DnsServer *dns_scope_get_dns_server(DnsScope *s) {
assert(s);
+ if (s->protocol != DNS_PROTOCOL_DNS)
+ return NULL;
+
if (s->link)
return link_get_dns_server(s->link);
else
void dns_scope_next_dns_server(DnsScope *s) {
assert(s);
+ if (s->protocol != DNS_PROTOCOL_DNS)
+ return;
+
if (s->link)
link_next_dns_server(s->link);
else
manager_next_dns_server(s->manager);
}
-int dns_scope_send(DnsScope *s, DnsPacket *p) {
- int ifindex = 0;
- DnsServer *srv;
- int r;
+int dns_scope_emit(DnsScope *s, DnsPacket *p) {
+ union in_addr_union addr;
+ int ifindex = 0, r;
+ int family;
+ uint16_t port;
+ uint32_t mtu;
+ int fd;
assert(s);
assert(p);
-
- srv = dns_scope_get_server(s);
- if (!srv)
- return -ESRCH;
+ assert(p->protocol == s->protocol);
if (s->link) {
- if (p->size > s->link->mtu)
- return -EMSGSIZE;
-
+ mtu = s->link->mtu;
ifindex = s->link->ifindex;
- } else {
- uint32_t mtu;
-
+ } else
mtu = manager_find_mtu(s->manager);
- if (mtu > 0) {
- if (p->size > mtu)
- return -EMSGSIZE;
- }
- }
- if (p->size > DNS_PACKET_UNICAST_SIZE_MAX)
- return -EMSGSIZE;
+ if (s->protocol == DNS_PROTOCOL_DNS) {
+ DnsServer *srv;
- if (srv->family == AF_INET)
- r = manager_dns_ipv4_send(s->manager, srv, ifindex, p);
- else if (srv->family == AF_INET6)
- r = manager_dns_ipv6_send(s->manager, srv, ifindex, p);
- else
+ if (DNS_PACKET_QDCOUNT(p) > 1)
+ return -ENOTSUP;
+
+ srv = dns_scope_get_dns_server(s);
+ if (!srv)
+ return -ESRCH;
+
+ family = srv->family;
+ addr = srv->address;
+ port = 53;
+
+ if (p->size > DNS_PACKET_UNICAST_SIZE_MAX)
+ return -EMSGSIZE;
+
+ if (p->size > mtu)
+ return -EMSGSIZE;
+
+ if (family == AF_INET)
+ fd = manager_dns_ipv4_fd(s->manager);
+ else if (family == AF_INET6)
+ fd = manager_dns_ipv6_fd(s->manager);
+ else
+ return -EAFNOSUPPORT;
+ if (fd < 0)
+ return fd;
+
+ } else if (s->protocol == DNS_PROTOCOL_LLMNR) {
+
+ if (DNS_PACKET_QDCOUNT(p) > 1)
+ return -ENOTSUP;
+
+ if (!ratelimit_test(&s->ratelimit))
+ return -EBUSY;
+
+ family = s->family;
+ port = 5355;
+
+ if (family == AF_INET) {
+ addr.in = LLMNR_MULTICAST_IPV4_ADDRESS;
+ fd = manager_llmnr_ipv4_udp_fd(s->manager);
+ } else if (family == AF_INET6) {
+ addr.in6 = LLMNR_MULTICAST_IPV6_ADDRESS;
+ fd = manager_llmnr_ipv6_udp_fd(s->manager);
+ } else
+ return -EAFNOSUPPORT;
+ if (fd < 0)
+ return fd;
+ } else
return -EAFNOSUPPORT;
+ r = manager_send(s->manager, fd, ifindex, family, &addr, port, p);
if (r < 0)
return r;
return 1;
}
-int dns_scope_tcp_socket(DnsScope *s) {
+int dns_scope_tcp_socket(DnsScope *s, int family, const union in_addr_union *address, uint16_t port) {
_cleanup_close_ int fd = -1;
union sockaddr_union sa = {};
socklen_t salen;
- int one, ifindex, ret;
- DnsServer *srv;
- int r;
+ static const int one = 1;
+ int ret, r;
assert(s);
+ assert((family == AF_UNSPEC) == !address);
+
+ if (family == AF_UNSPEC) {
+ DnsServer *srv;
+
+ srv = dns_scope_get_dns_server(s);
+ if (!srv)
+ return -ESRCH;
+
+ sa.sa.sa_family = srv->family;
+ if (srv->family == AF_INET) {
+ sa.in.sin_port = htobe16(port);
+ sa.in.sin_addr = srv->address.in;
+ salen = sizeof(sa.in);
+ } else if (srv->family == AF_INET6) {
+ sa.in6.sin6_port = htobe16(port);
+ sa.in6.sin6_addr = srv->address.in6;
+ sa.in6.sin6_scope_id = s->link ? s->link->ifindex : 0;
+ salen = sizeof(sa.in6);
+ } else
+ return -EAFNOSUPPORT;
+ } else {
+ sa.sa.sa_family = family;
+
+ if (family == AF_INET) {
+ sa.in.sin_port = htobe16(port);
+ sa.in.sin_addr = address->in;
+ salen = sizeof(sa.in);
+ } else if (family == AF_INET6) {
+ sa.in6.sin6_port = htobe16(port);
+ sa.in6.sin6_addr = address->in6;
+ sa.in6.sin6_scope_id = s->link ? s->link->ifindex : 0;
+ salen = sizeof(sa.in6);
+ } else
+ return -EAFNOSUPPORT;
+ }
- srv = dns_scope_get_server(s);
- if (!srv)
- return -ESRCH;
-
- if (s->link)
- ifindex = s->link->ifindex;
-
- sa.sa.sa_family = srv->family;
- if (srv->family == AF_INET) {
- sa.in.sin_port = htobe16(53);
- sa.in.sin_addr = srv->address.in;
- salen = sizeof(sa.in);
- } else if (srv->family == AF_INET6) {
- sa.in6.sin6_port = htobe16(53);
- sa.in6.sin6_addr = srv->address.in6;
- sa.in6.sin6_scope_id = ifindex;
- salen = sizeof(sa.in6);
- } else
- return -EAFNOSUPPORT;
-
- fd = socket(srv->family, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
+ fd = socket(sa.sa.sa_family, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
if (fd < 0)
return -errno;
- one = 1;
- setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &one, sizeof(one));
+ r = setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &one, sizeof(one));
+ if (r < 0)
+ return -errno;
+
+ if (s->link) {
+ uint32_t ifindex = htobe32(s->link->ifindex);
+
+ if (sa.sa.sa_family == AF_INET) {
+ r = setsockopt(fd, IPPROTO_IP, IP_UNICAST_IF, &ifindex, sizeof(ifindex));
+ if (r < 0)
+ return -errno;
+ } else if (sa.sa.sa_family == AF_INET6) {
+ r = setsockopt(fd, IPPROTO_IPV6, IPV6_UNICAST_IF, &ifindex, sizeof(ifindex));
+ if (r < 0)
+ return -errno;
+ }
+ }
+
+ if (s->protocol == DNS_PROTOCOL_LLMNR) {
+ /* RFC 4795, section 2.5 requires the TTL to be set to 1 */
+
+ if (sa.sa.sa_family == AF_INET) {
+ r = setsockopt(fd, IPPROTO_IP, IP_TTL, &one, sizeof(one));
+ if (r < 0)
+ return -errno;
+ } else if (sa.sa.sa_family == AF_INET6) {
+ r = setsockopt(fd, IPPROTO_IPV6, IPV6_UNICAST_HOPS, &one, sizeof(one));
+ if (r < 0)
+ return -errno;
+ }
+ }
r = connect(fd, &sa.sa, salen);
if (r < 0 && errno != EINPROGRESS)
ret = fd;
fd = -1;
+
return ret;
}
-DnsScopeMatch dns_scope_test(DnsScope *s, const char *domain) {
+DnsScopeMatch dns_scope_good_domain(DnsScope *s, int ifindex, uint64_t flags, const char *domain) {
char **i;
assert(s);
assert(domain);
+ if (ifindex != 0 && (!s->link || s->link->ifindex != ifindex))
+ return DNS_SCOPE_NO;
+
+ if ((SD_RESOLVED_FLAGS_MAKE(s->protocol, s->family) & flags) == 0)
+ return DNS_SCOPE_NO;
+
STRV_FOREACH(i, s->domains)
- if (dns_name_endswith(domain, *i))
+ if (dns_name_endswith(domain, *i) > 0)
return DNS_SCOPE_YES;
- if (dns_name_root(domain))
+ if (dns_name_root(domain) != 0)
return DNS_SCOPE_NO;
- if (s->type == DNS_SCOPE_MDNS) {
- if (dns_name_endswith(domain, "254.169.in-addr.arpa") ||
- dns_name_endswith(domain, "0.8.e.f.ip6.arpa"))
- return DNS_SCOPE_YES;
- else if (dns_name_endswith(domain, "local") ||
- !dns_name_single_label(domain))
+ if (is_localhost(domain))
+ return DNS_SCOPE_NO;
+
+ if (s->protocol == DNS_PROTOCOL_DNS) {
+ if (dns_name_endswith(domain, "254.169.in-addr.arpa") == 0 &&
+ dns_name_endswith(domain, "0.8.e.f.ip6.arpa") == 0 &&
+ dns_name_single_label(domain) == 0)
return DNS_SCOPE_MAYBE;
return DNS_SCOPE_NO;
}
- if (s->type == DNS_SCOPE_DNS) {
- if (dns_name_endswith(domain, "254.169.in-addr.arpa") ||
- dns_name_endswith(domain, "0.8.e.f.ip6.arpa") ||
- dns_name_single_label(domain))
- return DNS_SCOPE_NO;
+ if (s->protocol == DNS_PROTOCOL_MDNS) {
+ if (dns_name_endswith(domain, "254.169.in-addr.arpa") > 0 ||
+ dns_name_endswith(domain, "0.8.e.f.ip6.arpa") > 0 ||
+ (dns_name_endswith(domain, "local") > 0 && dns_name_equal(domain, "local") == 0))
+ return DNS_SCOPE_MAYBE;
+
+ return DNS_SCOPE_NO;
+ }
+
+ if (s->protocol == DNS_PROTOCOL_LLMNR) {
+ if (dns_name_endswith(domain, "in-addr.arpa") > 0 ||
+ dns_name_endswith(domain, "ip6.arpa") > 0 ||
+ dns_name_single_label(domain) > 0)
+ return DNS_SCOPE_MAYBE;
+
+ return DNS_SCOPE_NO;
+ }
+
+ assert_not_reached("Unknown scope protocol");
+}
+
+int dns_scope_good_key(DnsScope *s, DnsResourceKey *key) {
+ assert(s);
+ assert(key);
+
+ if (s->protocol == DNS_PROTOCOL_DNS)
+ return true;
+
+ /* On mDNS and LLMNR, send A and AAAA queries only on the
+ * respective scopes */
+
+ if (s->family == AF_INET && key->class == DNS_CLASS_IN && key->type == DNS_TYPE_AAAA)
+ return false;
+
+ if (s->family == AF_INET6 && key->class == DNS_CLASS_IN && key->type == DNS_TYPE_A)
+ return false;
+
+ return true;
+}
+
+int dns_scope_llmnr_membership(DnsScope *s, bool b) {
+ int fd;
+
+ assert(s);
+
+ if (s->protocol != DNS_PROTOCOL_LLMNR)
+ return 0;
+
+ assert(s->link);
+
+ if (s->family == AF_INET) {
+ struct ip_mreqn mreqn = {
+ .imr_multiaddr = LLMNR_MULTICAST_IPV4_ADDRESS,
+ .imr_ifindex = s->link->ifindex,
+ };
+
+ fd = manager_llmnr_ipv4_udp_fd(s->manager);
+ if (fd < 0)
+ return fd;
+
+ /* Always first try to drop membership before we add
+ * one. This is necessary on some devices, such as
+ * veth. */
+ if (b)
+ setsockopt(fd, IPPROTO_IP, IP_DROP_MEMBERSHIP, &mreqn, sizeof(mreqn));
+
+ if (setsockopt(fd, IPPROTO_IP, b ? IP_ADD_MEMBERSHIP : IP_DROP_MEMBERSHIP, &mreqn, sizeof(mreqn)) < 0)
+ return -errno;
+
+ } else if (s->family == AF_INET6) {
+ struct ipv6_mreq mreq = {
+ .ipv6mr_multiaddr = LLMNR_MULTICAST_IPV6_ADDRESS,
+ .ipv6mr_interface = s->link->ifindex,
+ };
+
+ fd = manager_llmnr_ipv6_udp_fd(s->manager);
+ if (fd < 0)
+ return fd;
+
+ if (b)
+ setsockopt(fd, IPPROTO_IPV6, IPV6_DROP_MEMBERSHIP, &mreq, sizeof(mreq));
+
+ if (setsockopt(fd, IPPROTO_IPV6, b ? IPV6_ADD_MEMBERSHIP : IPV6_DROP_MEMBERSHIP, &mreq, sizeof(mreq)) < 0)
+ return -errno;
+ } else
+ return -EAFNOSUPPORT;
+
+ return 0;
+}
+
+int dns_scope_good_dns_server(DnsScope *s, int family, const union in_addr_union *address) {
+ assert(s);
+ assert(address);
+
+ if (s->protocol != DNS_PROTOCOL_DNS)
+ return 1;
+
+ if (s->link)
+ return !!link_find_dns_server(s->link, family, address);
+ else
+ return !!manager_find_dns_server(s->manager, family, address);
+}
+
+static int dns_scope_make_reply_packet(
+ DnsScope *s,
+ uint16_t id,
+ int rcode,
+ DnsQuestion *q,
+ DnsAnswer *answer,
+ DnsAnswer *soa,
+ bool tentative,
+ DnsPacket **ret) {
+
+ _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL;
+ unsigned i;
+ int r;
+
+ assert(s);
+ assert(ret);
+
+ if ((!q || q->n_keys <= 0)
+ && (!answer || answer->n_rrs <= 0)
+ && (!soa || soa->n_rrs <= 0))
+ return -EINVAL;
+
+ r = dns_packet_new(&p, s->protocol, 0);
+ if (r < 0)
+ return r;
+
+ DNS_PACKET_HEADER(p)->id = id;
+ DNS_PACKET_HEADER(p)->flags = htobe16(DNS_PACKET_MAKE_FLAGS(
+ 1 /* qr */,
+ 0 /* opcode */,
+ 0 /* c */,
+ 0 /* tc */,
+ tentative,
+ 0 /* (ra) */,
+ 0 /* (ad) */,
+ 0 /* (cd) */,
+ rcode));
+
+ if (q) {
+ for (i = 0; i < q->n_keys; i++) {
+ r = dns_packet_append_key(p, q->keys[i], NULL);
+ if (r < 0)
+ return r;
+ }
+
+ DNS_PACKET_HEADER(p)->qdcount = htobe16(q->n_keys);
+ }
+
+ if (answer) {
+ for (i = 0; i < answer->n_rrs; i++) {
+ r = dns_packet_append_rr(p, answer->rrs[i], NULL);
+ if (r < 0)
+ return r;
+ }
+
+ DNS_PACKET_HEADER(p)->ancount = htobe16(answer->n_rrs);
+ }
+
+ if (soa) {
+ for (i = 0; i < soa->n_rrs; i++) {
+ r = dns_packet_append_rr(p, soa->rrs[i], NULL);
+ if (r < 0)
+ return r;
+ }
+
+ DNS_PACKET_HEADER(p)->arcount = htobe16(soa->n_rrs);
+ }
+
+ *ret = p;
+ p = NULL;
+
+ return 0;
+}
+
+static void dns_scope_verify_conflicts(DnsScope *s, DnsPacket *p) {
+ unsigned n;
+
+ assert(s);
+ assert(p);
+
+ if (p->question)
+ for (n = 0; n < p->question->n_keys; n++)
+ dns_zone_verify_conflicts(&s->zone, p->question->keys[n]);
+ if (p->answer)
+ for (n = 0; n < p->answer->n_rrs; n++)
+ dns_zone_verify_conflicts(&s->zone, p->answer->rrs[n]->key);
+}
+
+void dns_scope_process_query(DnsScope *s, DnsStream *stream, DnsPacket *p) {
+ _cleanup_(dns_packet_unrefp) DnsPacket *reply = NULL;
+ _cleanup_(dns_answer_unrefp) DnsAnswer *answer = NULL, *soa = NULL;
+ bool tentative = false;
+ int r, fd;
+
+ assert(s);
+ assert(p);
+
+ if (p->protocol != DNS_PROTOCOL_LLMNR)
+ return;
+
+ if (p->ipproto == IPPROTO_UDP) {
+ /* Don't accept UDP queries directed to anything but
+ * the LLMNR multicast addresses. See RFC 4795,
+ * section 2.5.*/
+
+ if (p->family == AF_INET && !in_addr_equal(AF_INET, &p->destination, (union in_addr_union*) &LLMNR_MULTICAST_IPV4_ADDRESS))
+ return;
+
+ if (p->family == AF_INET6 && !in_addr_equal(AF_INET6, &p->destination, (union in_addr_union*) &LLMNR_MULTICAST_IPV6_ADDRESS))
+ return;
+ }
+
+ r = dns_packet_extract(p);
+ if (r < 0) {
+ log_debug("Failed to extract resources from incoming packet: %s", strerror(-r));
+ return;
+ }
- return DNS_SCOPE_MAYBE;
+ if (DNS_PACKET_C(p)) {
+ /* Somebody notified us about a possible conflict */
+ dns_scope_verify_conflicts(s, p);
+ return;
}
- assert_not_reached("Unknown scope type");
+ r = dns_zone_lookup(&s->zone, p->question, &answer, &soa, &tentative);
+ if (r < 0) {
+ log_debug("Failed to lookup key: %s", strerror(-r));
+ return;
+ }
+ if (r == 0)
+ return;
+
+ if (answer)
+ dns_answer_order_by_scope(answer, in_addr_is_link_local(p->family, &p->sender) > 0);
+
+ r = dns_scope_make_reply_packet(s, DNS_PACKET_ID(p), DNS_RCODE_SUCCESS, p->question, answer, soa, tentative, &reply);
+ if (r < 0) {
+ log_debug("Failed to build reply packet: %s", strerror(-r));
+ return;
+ }
+
+ if (stream)
+ r = dns_stream_write_packet(stream, reply);
+ else {
+ if (!ratelimit_test(&s->ratelimit))
+ return;
+
+ if (p->family == AF_INET)
+ fd = manager_llmnr_ipv4_udp_fd(s->manager);
+ else if (p->family == AF_INET6)
+ fd = manager_llmnr_ipv6_udp_fd(s->manager);
+ else {
+ log_debug("Unknown protocol");
+ return;
+ }
+ if (fd < 0) {
+ log_debug("Failed to get reply socket: %s", strerror(-fd));
+ return;
+ }
+
+ /* Note that we always immediately reply to all LLMNR
+ * requests, and do not wait any time, since we
+ * verified uniqueness for all records. Also see RFC
+ * 4795, Section 2.7 */
+
+ r = manager_send(s->manager, fd, p->ifindex, p->family, &p->sender, p->sender_port, reply);
+ }
+
+ if (r < 0) {
+ log_debug("Failed to send reply packet: %s", strerror(-r));
+ return;
+ }
+}
+
+DnsTransaction *dns_scope_find_transaction(DnsScope *scope, DnsQuestion *question, bool cache_ok) {
+ DnsTransaction *t;
+
+ assert(scope);
+ assert(question);
+
+ /* Try to find an ongoing transaction that is a equal or a
+ * superset of the specified question */
+
+ LIST_FOREACH(transactions_by_scope, t, scope->transactions) {
+
+ /* Refuse reusing transactions that completed based on
+ * cached data instead of a real packet, if that's
+ * requested. */
+ if (!cache_ok &&
+ IN_SET(t->state, DNS_TRANSACTION_SUCCESS, DNS_TRANSACTION_FAILURE) &&
+ !t->received)
+ continue;
+
+ if (dns_question_is_superset(t->question, question) > 0)
+ return t;
+ }
+
+ return NULL;
+}
+
+static int dns_scope_make_conflict_packet(
+ DnsScope *s,
+ DnsResourceRecord *rr,
+ DnsPacket **ret) {
+
+ _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL;
+ int r;
+
+ assert(s);
+ assert(rr);
+ assert(ret);
+
+ r = dns_packet_new(&p, s->protocol, 0);
+ if (r < 0)
+ return r;
+
+ DNS_PACKET_HEADER(p)->flags = htobe16(DNS_PACKET_MAKE_FLAGS(
+ 0 /* qr */,
+ 0 /* opcode */,
+ 1 /* conflict */,
+ 0 /* tc */,
+ 0 /* t */,
+ 0 /* (ra) */,
+ 0 /* (ad) */,
+ 0 /* (cd) */,
+ 0));
+ random_bytes(&DNS_PACKET_HEADER(p)->id, sizeof(uint16_t));
+ DNS_PACKET_HEADER(p)->qdcount = htobe16(1);
+ DNS_PACKET_HEADER(p)->arcount = htobe16(1);
+
+ r = dns_packet_append_key(p, rr->key, NULL);
+ if (r < 0)
+ return r;
+
+ r = dns_packet_append_rr(p, rr, NULL);
+ if (r < 0)
+ return r;
+
+ *ret = p;
+ p = NULL;
+
+ return 0;
+}
+
+static int on_conflict_dispatch(sd_event_source *es, usec_t usec, void *userdata) {
+ DnsScope *scope = userdata;
+ int r;
+
+ assert(es);
+ assert(scope);
+
+ scope->conflict_event_source = sd_event_source_unref(scope->conflict_event_source);
+
+ for (;;) {
+ _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *rr = NULL;
+ _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL;
+
+ rr = ordered_hashmap_steal_first(scope->conflict_queue);
+ if (!rr)
+ break;
+
+ r = dns_scope_make_conflict_packet(scope, rr, &p);
+ if (r < 0) {
+ log_error("Failed to make conflict packet: %s", strerror(-r));
+ return 0;
+ }
+
+ r = dns_scope_emit(scope, p);
+ if (r < 0)
+ log_debug("Failed to send conflict packet: %s", strerror(-r));
+ }
+
+ return 0;
+}
+
+int dns_scope_notify_conflict(DnsScope *scope, DnsResourceRecord *rr) {
+ usec_t jitter;
+ int r;
+
+ assert(scope);
+ assert(rr);
+
+ /* We don't send these queries immediately. Instead, we queue
+ * them, and send them after some jitter delay. */
+ r = ordered_hashmap_ensure_allocated(&scope->conflict_queue, &dns_resource_key_hash_ops);
+ if (r < 0) {
+ log_oom();
+ return r;
+ }
+
+ /* We only place one RR per key in the conflict
+ * messages, not all of them. That should be enough to
+ * indicate where there might be a conflict */
+ r = ordered_hashmap_put(scope->conflict_queue, rr->key, rr);
+ if (r == -EEXIST || r == 0)
+ return 0;
+ if (r < 0) {
+ log_debug("Failed to queue conflicting RR: %s", strerror(-r));
+ return r;
+ }
+
+ dns_resource_record_ref(rr);
+
+ if (scope->conflict_event_source)
+ return 0;
+
+ random_bytes(&jitter, sizeof(jitter));
+ jitter %= LLMNR_JITTER_INTERVAL_USEC;
+
+ r = sd_event_add_time(scope->manager->event,
+ &scope->conflict_event_source,
+ clock_boottime_or_monotonic(),
+ now(clock_boottime_or_monotonic()) + jitter,
+ LLMNR_JITTER_INTERVAL_USEC,
+ on_conflict_dispatch, scope);
+ if (r < 0) {
+ log_debug("Failed to add conflict dispatch event: %s", strerror(-r));
+ return r;
+ }
+
+ return 0;
+}
+
+void dns_scope_check_conflicts(DnsScope *scope, DnsPacket *p) {
+ unsigned i;
+ int r;
+
+ assert(scope);
+ assert(p);
+
+ if (p->protocol != DNS_PROTOCOL_LLMNR)
+ return;
+
+ if (DNS_PACKET_RRCOUNT(p) <= 0)
+ return;
+
+ if (DNS_PACKET_C(p) != 0)
+ return;
+
+ if (DNS_PACKET_T(p) != 0)
+ return;
+
+ if (manager_our_packet(scope->manager, p))
+ return;
+
+ r = dns_packet_extract(p);
+ if (r < 0) {
+ log_debug("Failed to extract packet: %s", strerror(-r));
+ return;
+ }
+
+ log_debug("Checking for conflicts...");
+
+ for (i = 0; i < p->answer->n_rrs; i++) {
+
+ /* Check for conflicts against the local zone. If we
+ * found one, we won't check any further */
+ r = dns_zone_check_conflicts(&scope->zone, p->answer->rrs[i]);
+ if (r != 0)
+ continue;
+
+ /* Check for conflicts against the local cache. If so,
+ * send out an advisory query, to inform everybody */
+ r = dns_cache_check_conflicts(&scope->cache, p->answer->rrs[i], p->family, &p->sender);
+ if (r <= 0)
+ continue;
+
+ dns_scope_notify_conflict(scope, p->answer->rrs[i]);
+ }
}
~ianmdlvl / elogind.git / blobdiff