#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, Link *l, DnsProtocol protocol, int family) {
DnsScope *s;
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) {
- DnsQueryTransaction *t;
+ DnsTransaction *t;
if (!s)
return NULL;
* freed while we still look at it */
t->block_gc++;
- dns_query_transaction_complete(t, DNS_QUERY_ABORTED);
+ dns_transaction_complete(t, DNS_TRANSACTION_ABORTED);
t->block_gc--;
- dns_query_transaction_free(t);
+ dns_transaction_free(t);
}
dns_cache_flush(&s->cache);
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)
if (DNS_PACKET_QDCOUNT(p) > 1)
return -ENOTSUP;
- srv = dns_scope_get_server(s);
+ srv = dns_scope_get_dns_server(s);
if (!srv)
return -ESRCH;
if (DNS_PACKET_QDCOUNT(p) > 1)
return -ENOTSUP;
+ if (!ratelimit_test(&s->ratelimit))
+ return -EBUSY;
+
family = s->family;
port = 5355;
if (family == AF_UNSPEC) {
DnsServer *srv;
- srv = dns_scope_get_server(s);
+ srv = dns_scope_get_dns_server(s);
if (!srv)
return -ESRCH;
}
if (s->protocol == DNS_PROTOCOL_LLMNR) {
- /* RFC 4795, section 2.5 suggests the TTL to be set to 1 */
+ /* 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 (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;
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 !!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 *a, DnsPacket **ret) {
+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);
- if (q->n_keys <= 0 && a->n_rrs <= 0)
+ 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);
return r;
DNS_PACKET_HEADER(p)->id = id;
- DNS_PACKET_HEADER(p)->flags = htobe16(DNS_PACKET_MAKE_FLAGS(1, 0, 0, 0, 0, 0, 0, 0, rcode));
+ 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++) {
DNS_PACKET_HEADER(p)->qdcount = htobe16(q->n_keys);
}
- if (a) {
- for (i = 0; i < a->n_rrs; i++) {
- r = dns_packet_append_rr(p, a->rrs[i], NULL);
+ 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(a->n_rrs);
+ 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;
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;
+ _cleanup_(dns_answer_unrefp) DnsAnswer *answer = NULL, *soa = NULL;
+ bool tentative = false;
int r, fd;
assert(s);
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;
}
- r = dns_zone_lookup(&s->zone, p->question, &answer);
+ if (DNS_PACKET_C(p)) {
+ /* FIXME: Somebody notified us about a likely conflict */
+ return;
+ }
+
+ 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;
- r = dns_scope_make_reply_packet(s, DNS_PACKET_ID(p), DNS_RCODE_SUCCESS, p->question, answer, &reply);
+ 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)
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);
}
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;
+}
~ianmdlvl / elogind.git / blobdiff