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Diffstat (limited to 'src/resolve/resolved-dns-scope.c')
-rw-r--r--src/resolve/resolved-dns-scope.c84
1 files changed, 52 insertions, 32 deletions
diff --git a/src/resolve/resolved-dns-scope.c b/src/resolve/resolved-dns-scope.c
index 0aab1e35d3..b8414da87e 100644
--- a/src/resolve/resolved-dns-scope.c
+++ b/src/resolve/resolved-dns-scope.c
@@ -34,6 +34,10 @@
#define MULTICAST_RATELIMIT_INTERVAL_USEC (1*USEC_PER_SEC)
#define MULTICAST_RATELIMIT_BURST 1000
+/* After how much time to repeat LLMNR requests, see RFC 4795 Section 7 */
+#define MULTICAST_RESEND_TIMEOUT_MIN_USEC (100 * USEC_PER_MSEC)
+#define MULTICAST_RESEND_TIMEOUT_MAX_USEC (1 * USEC_PER_SEC)
+
int dns_scope_new(Manager *m, DnsScope **ret, Link *l, DnsProtocol protocol, int family) {
DnsScope *s;
@@ -48,6 +52,7 @@ int dns_scope_new(Manager *m, DnsScope **ret, Link *l, DnsProtocol protocol, int
s->link = l;
s->protocol = protocol;
s->family = family;
+ s->resend_timeout = MULTICAST_RESEND_TIMEOUT_MIN_USEC;
LIST_PREPEND(scopes, m->dns_scopes, s);
@@ -125,18 +130,34 @@ void dns_scope_next_dns_server(DnsScope *s) {
manager_next_dns_server(s->manager);
}
-int dns_scope_emit(DnsScope *s, DnsTransaction *t, DnsPacket *p, DnsServer **server) {
- DnsServer *srv = NULL;
+void dns_scope_packet_received(DnsScope *s, usec_t rtt) {
+ assert(s);
+
+ if (rtt > s->max_rtt) {
+ s->max_rtt = rtt;
+ s->resend_timeout = MIN(MAX(MULTICAST_RESEND_TIMEOUT_MIN_USEC, s->max_rtt * 2),
+ MULTICAST_RESEND_TIMEOUT_MAX_USEC);
+ }
+}
+
+void dns_scope_packet_lost(DnsScope *s, usec_t usec) {
+ assert(s);
+
+ if (s->resend_timeout <= usec)
+ s->resend_timeout = MIN(s->resend_timeout * 2, MULTICAST_RESEND_TIMEOUT_MAX_USEC);
+}
+
+int dns_scope_emit(DnsScope *s, int fd, 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);
assert(p->protocol == s->protocol);
+ assert((s->protocol == DNS_PROTOCOL_DNS) != (fd < 0));
if (s->link) {
mtu = s->link->mtu;
@@ -148,28 +169,15 @@ int dns_scope_emit(DnsScope *s, DnsTransaction *t, DnsPacket *p, DnsServer **ser
if (DNS_PACKET_QDCOUNT(p) > 1)
return -EOPNOTSUPP;
- 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 + UDP_PACKET_HEADER_SIZE > mtu)
return -EMSGSIZE;
- if (family == AF_INET)
- fd = transaction_dns_ipv4_fd(t);
- else if (family == AF_INET6)
- fd = transaction_dns_ipv6_fd(t);
- else
- return -EAFNOSUPPORT;
- if (fd < 0)
- return fd;
+ r = manager_write(s->manager, fd, p);
+ if (r < 0)
+ return r;
} else if (s->protocol == DNS_PROTOCOL_LLMNR) {
@@ -192,20 +200,17 @@ int dns_scope_emit(DnsScope *s, DnsTransaction *t, DnsPacket *p, DnsServer **ser
return -EAFNOSUPPORT;
if (fd < 0)
return fd;
+
+ r = manager_send(s->manager, fd, ifindex, family, &addr, port, p);
+ if (r < 0)
+ return r;
} else
return -EAFNOSUPPORT;
- r = manager_send(s->manager, fd, ifindex, family, &addr, port, p);
- if (r < 0)
- return r;
-
- if (server)
- *server = srv;
-
return 1;
}
-int dns_scope_tcp_socket(DnsScope *s, int family, const union in_addr_union *address, uint16_t port, DnsServer **server) {
+static int dns_scope_socket(DnsScope *s, int type, int family, const union in_addr_union *address, uint16_t port, DnsServer **server) {
DnsServer *srv = NULL;
_cleanup_close_ int fd = -1;
union sockaddr_union sa = {};
@@ -249,13 +254,15 @@ int dns_scope_tcp_socket(DnsScope *s, int family, const union in_addr_union *add
return -EAFNOSUPPORT;
}
- fd = socket(sa.sa.sa_family, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
+ fd = socket(sa.sa.sa_family, type|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
if (fd < 0)
return -errno;
- r = setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &one, sizeof(one));
- if (r < 0)
- return -errno;
+ if (type == SOCK_STREAM) {
+ 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);
@@ -298,6 +305,14 @@ int dns_scope_tcp_socket(DnsScope *s, int family, const union in_addr_union *add
return ret;
}
+int dns_scope_udp_dns_socket(DnsScope *s, DnsServer **server) {
+ return dns_scope_socket(s, SOCK_DGRAM, AF_UNSPEC, NULL, 53, server);
+}
+
+int dns_scope_tcp_socket(DnsScope *s, int family, const union in_addr_union *address, uint16_t port, DnsServer **server) {
+ return dns_scope_socket(s, SOCK_STREAM, family, address, port, server);
+}
+
DnsScopeMatch dns_scope_good_domain(DnsScope *s, int ifindex, uint64_t flags, const char *domain) {
char **i;
@@ -320,6 +335,11 @@ DnsScopeMatch dns_scope_good_domain(DnsScope *s, int ifindex, uint64_t flags, co
if (is_localhost(domain))
return DNS_SCOPE_NO;
+ /* Never resolve any loopback IP address via DNS, LLMNR or mDNS */
+ if (dns_name_endswith(domain, "127.in-addr.arpa") > 0 ||
+ dns_name_equal(domain, "1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.ip6.arpa") > 0)
+ 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 &&
@@ -687,7 +707,7 @@ static int on_conflict_dispatch(sd_event_source *es, usec_t usec, void *userdata
return 0;
}
- r = dns_scope_emit(scope, NULL, p, NULL);
+ r = dns_scope_emit(scope, -1, p);
if (r < 0)
log_debug_errno(r, "Failed to send conflict packet: %m");
}
generated by cgit v1.2.3-54-g00ecf (git 2.45.2) at 2024-08-12 11:33:43 +0000