1 /* SPDX-License-Identifier: LGPL-2.1+ */
3 #include <netinet/tcp.h>
5 #include "alloc-util.h"
9 #include "resolved-dns-stream.h"
11 #define DNS_STREAM_TIMEOUT_USEC (10 * USEC_PER_SEC)
12 #define DNS_STREAMS_MAX 128
14 #define WRITE_TLS_DATA 1
16 static void dns_stream_stop(DnsStream
*s
) {
19 s
->io_event_source
= sd_event_source_unref(s
->io_event_source
);
20 s
->timeout_event_source
= sd_event_source_unref(s
->timeout_event_source
);
21 s
->fd
= safe_close(s
->fd
);
24 static int dns_stream_update_io(DnsStream
*s
) {
29 if (s
->write_packet
&& s
->n_written
< sizeof(s
->write_size
) + s
->write_packet
->size
)
31 else if (!ordered_set_isempty(s
->write_queue
)) {
32 dns_packet_unref(s
->write_packet
);
33 s
->write_packet
= ordered_set_steal_first(s
->write_queue
);
34 s
->write_size
= htobe16(s
->write_packet
->size
);
38 if (!s
->read_packet
|| s
->n_read
< sizeof(s
->read_size
) + s
->read_packet
->size
)
41 return sd_event_source_set_io_events(s
->io_event_source
, f
);
44 static int dns_stream_complete(DnsStream
*s
, int error
) {
48 if (s
->tls_session
&& IN_SET(error
, ETIMEDOUT
, 0)) {
51 r
= gnutls_bye(s
->tls_session
, GNUTLS_SHUT_RDWR
);
52 if (r
== GNUTLS_E_AGAIN
&& !s
->tls_bye
) {
53 dns_stream_ref(s
); /* keep reference for closing TLS session */
62 s
->complete(s
, error
);
63 else /* the default action if no completion function is set is to close the stream */
69 static int dns_stream_identify(DnsStream
*s
) {
71 struct cmsghdr header
; /* For alignment */
72 uint8_t buffer
[CMSG_SPACE(MAXSIZE(struct in_pktinfo
, struct in6_pktinfo
))
73 + EXTRA_CMSG_SPACE
/* kernel appears to require extra space */];
75 struct msghdr mh
= {};
85 /* Query the local side */
86 s
->local_salen
= sizeof(s
->local
);
87 r
= getsockname(s
->fd
, &s
->local
.sa
, &s
->local_salen
);
90 if (s
->local
.sa
.sa_family
== AF_INET6
&& s
->ifindex
<= 0)
91 s
->ifindex
= s
->local
.in6
.sin6_scope_id
;
93 /* Query the remote side */
94 s
->peer_salen
= sizeof(s
->peer
);
95 r
= getpeername(s
->fd
, &s
->peer
.sa
, &s
->peer_salen
);
98 if (s
->peer
.sa
.sa_family
== AF_INET6
&& s
->ifindex
<= 0)
99 s
->ifindex
= s
->peer
.in6
.sin6_scope_id
;
101 /* Check consistency */
102 assert(s
->peer
.sa
.sa_family
== s
->local
.sa
.sa_family
);
103 assert(IN_SET(s
->peer
.sa
.sa_family
, AF_INET
, AF_INET6
));
105 /* Query connection meta information */
106 sl
= sizeof(control
);
107 if (s
->peer
.sa
.sa_family
== AF_INET
) {
108 r
= getsockopt(s
->fd
, IPPROTO_IP
, IP_PKTOPTIONS
, &control
, &sl
);
111 } else if (s
->peer
.sa
.sa_family
== AF_INET6
) {
113 r
= getsockopt(s
->fd
, IPPROTO_IPV6
, IPV6_2292PKTOPTIONS
, &control
, &sl
);
117 return -EAFNOSUPPORT
;
119 mh
.msg_control
= &control
;
120 mh
.msg_controllen
= sl
;
122 CMSG_FOREACH(cmsg
, &mh
) {
124 if (cmsg
->cmsg_level
== IPPROTO_IPV6
) {
125 assert(s
->peer
.sa
.sa_family
== AF_INET6
);
127 switch (cmsg
->cmsg_type
) {
130 struct in6_pktinfo
*i
= (struct in6_pktinfo
*) CMSG_DATA(cmsg
);
133 s
->ifindex
= i
->ipi6_ifindex
;
138 s
->ttl
= *(int *) CMSG_DATA(cmsg
);
142 } else if (cmsg
->cmsg_level
== IPPROTO_IP
) {
143 assert(s
->peer
.sa
.sa_family
== AF_INET
);
145 switch (cmsg
->cmsg_type
) {
148 struct in_pktinfo
*i
= (struct in_pktinfo
*) CMSG_DATA(cmsg
);
151 s
->ifindex
= i
->ipi_ifindex
;
156 s
->ttl
= *(int *) CMSG_DATA(cmsg
);
162 /* The Linux kernel sets the interface index to the loopback
163 * device if the connection came from the local host since it
164 * avoids the routing table in such a case. Let's unset the
165 * interface index in such a case. */
166 if (s
->ifindex
== LOOPBACK_IFINDEX
)
169 /* If we don't know the interface index still, we look for the
170 * first local interface with a matching address. Yuck! */
172 s
->ifindex
= manager_find_ifindex(s
->manager
, s
->local
.sa
.sa_family
, s
->local
.sa
.sa_family
== AF_INET
? (union in_addr_union
*) &s
->local
.in
.sin_addr
: (union in_addr_union
*) &s
->local
.in6
.sin6_addr
);
174 if (s
->protocol
== DNS_PROTOCOL_LLMNR
&& s
->ifindex
> 0) {
175 uint32_t ifindex
= htobe32(s
->ifindex
);
177 /* Make sure all packets for this connection are sent on the same interface */
178 if (s
->local
.sa
.sa_family
== AF_INET
) {
179 r
= setsockopt(s
->fd
, IPPROTO_IP
, IP_UNICAST_IF
, &ifindex
, sizeof(ifindex
));
181 log_debug_errno(errno
, "Failed to invoke IP_UNICAST_IF: %m");
182 } else if (s
->local
.sa
.sa_family
== AF_INET6
) {
183 r
= setsockopt(s
->fd
, IPPROTO_IPV6
, IPV6_UNICAST_IF
, &ifindex
, sizeof(ifindex
));
185 log_debug_errno(errno
, "Failed to invoke IPV6_UNICAST_IF: %m");
189 s
->identified
= true;
194 static ssize_t
dns_stream_writev(DnsStream
*s
, const struct iovec
*iov
, size_t iovcnt
, int flags
) {
201 if (s
->tls_session
&& !(flags
& WRITE_TLS_DATA
)) {
206 for (i
= 0; i
< iovcnt
; i
++) {
207 ss
= gnutls_record_send(s
->tls_session
, iov
[i
].iov_base
, iov
[i
].iov_len
);
211 case GNUTLS_E_INTERRUPTED
:
216 log_debug("Failed to invoke gnutls_record_send: %s", gnutls_strerror(ss
));
222 if (ss
!= (ssize_t
) iov
[i
].iov_len
)
227 if (s
->tfo_salen
> 0) {
228 struct msghdr hdr
= {
229 .msg_iov
= (struct iovec
*) iov
,
230 .msg_iovlen
= iovcnt
,
231 .msg_name
= &s
->tfo_address
.sa
,
232 .msg_namelen
= s
->tfo_salen
235 r
= sendmsg(s
->fd
, &hdr
, MSG_FASTOPEN
);
237 if (errno
== EOPNOTSUPP
) {
239 r
= connect(s
->fd
, &s
->tfo_address
.sa
, s
->tfo_salen
);
244 } else if (errno
== EINPROGRESS
)
247 s
->tfo_salen
= 0; /* connection is made */
249 r
= writev(s
->fd
, iov
, iovcnt
);
257 static ssize_t
dns_stream_read(DnsStream
*s
, void *buf
, size_t count
) {
261 if (s
->tls_session
) {
262 ss
= gnutls_record_recv(s
->tls_session
, buf
, count
);
266 case GNUTLS_E_INTERRUPTED
:
271 log_debug("Failed to invoke gnutls_record_send: %s", gnutls_strerror(ss
));
274 } else if (s
->on_connection
) {
277 r
= s
->on_connection(s
);
278 s
->on_connection
= NULL
; /* only call once */
285 ss
= read(s
->fd
, buf
, count
);
294 static ssize_t
dns_stream_tls_writev(gnutls_transport_ptr_t p
, const giovec_t
* iov
, int iovcnt
) {
299 r
= dns_stream_writev((DnsStream
*) p
, (struct iovec
*) iov
, iovcnt
, WRITE_TLS_DATA
);
309 static int on_stream_timeout(sd_event_source
*es
, usec_t usec
, void *userdata
) {
310 DnsStream
*s
= userdata
;
314 return dns_stream_complete(s
, ETIMEDOUT
);
317 static int on_stream_io(sd_event_source
*es
, int fd
, uint32_t revents
, void *userdata
) {
318 DnsStream
*s
= userdata
;
325 assert(s
->tls_session
);
327 r
= gnutls_bye(s
->tls_session
, GNUTLS_SHUT_RDWR
);
328 if (r
!= GNUTLS_E_AGAIN
) {
336 if (s
->tls_handshake
< 0) {
337 assert(s
->tls_session
);
339 s
->tls_handshake
= gnutls_handshake(s
->tls_session
);
340 if (s
->tls_handshake
>= 0) {
341 if (s
->on_connection
&& !(gnutls_session_get_flags(s
->tls_session
) & GNUTLS_SFLAGS_FALSE_START
)) {
342 r
= s
->on_connection(s
);
343 s
->on_connection
= NULL
; /* only call once */
348 if (gnutls_error_is_fatal(s
->tls_handshake
))
349 return dns_stream_complete(s
, ECONNREFUSED
);
357 /* only identify after connecting */
358 if (s
->tfo_salen
== 0) {
359 r
= dns_stream_identify(s
);
361 return dns_stream_complete(s
, -r
);
364 if ((revents
& EPOLLOUT
) &&
366 s
->n_written
< sizeof(s
->write_size
) + s
->write_packet
->size
) {
371 iov
[0].iov_base
= &s
->write_size
;
372 iov
[0].iov_len
= sizeof(s
->write_size
);
373 iov
[1].iov_base
= DNS_PACKET_DATA(s
->write_packet
);
374 iov
[1].iov_len
= s
->write_packet
->size
;
376 IOVEC_INCREMENT(iov
, 2, s
->n_written
);
378 ss
= dns_stream_writev(s
, iov
, 2, 0);
380 if (!IN_SET(-ss
, EINTR
, EAGAIN
))
381 return dns_stream_complete(s
, -ss
);
385 /* Are we done? If so, disable the event source for EPOLLOUT */
386 if (s
->n_written
>= sizeof(s
->write_size
) + s
->write_packet
->size
) {
387 r
= dns_stream_update_io(s
);
389 return dns_stream_complete(s
, -r
);
393 if ((revents
& (EPOLLIN
|EPOLLHUP
|EPOLLRDHUP
)) &&
395 s
->n_read
< sizeof(s
->read_size
) + s
->read_packet
->size
)) {
397 if (s
->n_read
< sizeof(s
->read_size
)) {
400 ss
= dns_stream_read(s
, (uint8_t*) &s
->read_size
+ s
->n_read
, sizeof(s
->read_size
) - s
->n_read
);
402 if (!IN_SET(-ss
, EINTR
, EAGAIN
))
403 return dns_stream_complete(s
, -ss
);
405 return dns_stream_complete(s
, ECONNRESET
);
410 if (s
->n_read
>= sizeof(s
->read_size
)) {
412 if (be16toh(s
->read_size
) < DNS_PACKET_HEADER_SIZE
)
413 return dns_stream_complete(s
, EBADMSG
);
415 if (s
->n_read
< sizeof(s
->read_size
) + be16toh(s
->read_size
)) {
418 if (!s
->read_packet
) {
419 r
= dns_packet_new(&s
->read_packet
, s
->protocol
, be16toh(s
->read_size
), DNS_PACKET_SIZE_MAX
);
421 return dns_stream_complete(s
, -r
);
423 s
->read_packet
->size
= be16toh(s
->read_size
);
424 s
->read_packet
->ipproto
= IPPROTO_TCP
;
425 s
->read_packet
->family
= s
->peer
.sa
.sa_family
;
426 s
->read_packet
->ttl
= s
->ttl
;
427 s
->read_packet
->ifindex
= s
->ifindex
;
429 if (s
->read_packet
->family
== AF_INET
) {
430 s
->read_packet
->sender
.in
= s
->peer
.in
.sin_addr
;
431 s
->read_packet
->sender_port
= be16toh(s
->peer
.in
.sin_port
);
432 s
->read_packet
->destination
.in
= s
->local
.in
.sin_addr
;
433 s
->read_packet
->destination_port
= be16toh(s
->local
.in
.sin_port
);
435 assert(s
->read_packet
->family
== AF_INET6
);
436 s
->read_packet
->sender
.in6
= s
->peer
.in6
.sin6_addr
;
437 s
->read_packet
->sender_port
= be16toh(s
->peer
.in6
.sin6_port
);
438 s
->read_packet
->destination
.in6
= s
->local
.in6
.sin6_addr
;
439 s
->read_packet
->destination_port
= be16toh(s
->local
.in6
.sin6_port
);
441 if (s
->read_packet
->ifindex
== 0)
442 s
->read_packet
->ifindex
= s
->peer
.in6
.sin6_scope_id
;
443 if (s
->read_packet
->ifindex
== 0)
444 s
->read_packet
->ifindex
= s
->local
.in6
.sin6_scope_id
;
448 ss
= dns_stream_read(s
,
449 (uint8_t*) DNS_PACKET_DATA(s
->read_packet
) + s
->n_read
- sizeof(s
->read_size
),
450 sizeof(s
->read_size
) + be16toh(s
->read_size
) - s
->n_read
);
452 if (!IN_SET(errno
, EINTR
, EAGAIN
))
453 return dns_stream_complete(s
, errno
);
455 return dns_stream_complete(s
, ECONNRESET
);
460 /* Are we done? If so, disable the event source for EPOLLIN */
461 if (s
->n_read
>= sizeof(s
->read_size
) + be16toh(s
->read_size
)) {
462 /* If there's a packet handler
463 * installed, call that. Note that
464 * this is optional... */
471 r
= dns_stream_update_io(s
);
473 return dns_stream_complete(s
, -r
);
478 if ((s
->write_packet
&& s
->n_written
>= sizeof(s
->write_size
) + s
->write_packet
->size
) &&
479 (s
->read_packet
&& s
->n_read
>= sizeof(s
->read_size
) + s
->read_packet
->size
))
480 return dns_stream_complete(s
, 0);
485 DnsStream
*dns_stream_unref(DnsStream
*s
) {
492 assert(s
->n_ref
> 0);
500 if (s
->server
&& s
->server
->stream
== s
)
501 s
->server
->stream
= NULL
;
504 LIST_REMOVE(streams
, s
->manager
->dns_streams
, s
);
505 s
->manager
->n_dns_streams
--;
510 gnutls_deinit(s
->tls_session
);
513 ORDERED_SET_FOREACH(p
, s
->write_queue
, i
)
514 dns_packet_unref(ordered_set_remove(s
->write_queue
, p
));
516 dns_packet_unref(s
->write_packet
);
517 dns_packet_unref(s
->read_packet
);
518 dns_server_unref(s
->server
);
520 ordered_set_free(s
->write_queue
);
525 DnsStream
*dns_stream_ref(DnsStream
*s
) {
529 assert(s
->n_ref
> 0);
535 int dns_stream_new(Manager
*m
, DnsStream
**ret
, DnsProtocol protocol
, int fd
, const union sockaddr_union
*tfo_address
) {
536 _cleanup_(dns_stream_unrefp
) DnsStream
*s
= NULL
;
542 if (m
->n_dns_streams
> DNS_STREAMS_MAX
)
545 s
= new0(DnsStream
, 1);
549 r
= ordered_set_ensure_allocated(&s
->write_queue
, &dns_packet_hash_ops
);
555 s
->protocol
= protocol
;
557 r
= sd_event_add_io(m
->event
, &s
->io_event_source
, fd
, EPOLLIN
, on_stream_io
, s
);
561 (void) sd_event_source_set_description(s
->io_event_source
, "dns-stream-io");
563 r
= sd_event_add_time(
565 &s
->timeout_event_source
,
566 clock_boottime_or_monotonic(),
567 now(clock_boottime_or_monotonic()) + DNS_STREAM_TIMEOUT_USEC
, 0,
568 on_stream_timeout
, s
);
572 (void) sd_event_source_set_description(s
->timeout_event_source
, "dns-stream-timeout");
574 LIST_PREPEND(streams
, m
->dns_streams
, s
);
578 s
->tfo_address
= *tfo_address
;
579 s
->tfo_salen
= tfo_address
->sa
.sa_family
== AF_INET6
? sizeof(tfo_address
->in6
) : sizeof(tfo_address
->in
);
590 int dns_stream_connect_tls(DnsStream
*s
, gnutls_session_t tls_session
) {
591 gnutls_transport_set_ptr2(tls_session
, (gnutls_transport_ptr_t
) (long) s
->fd
, s
);
592 gnutls_transport_set_vec_push_function(tls_session
, &dns_stream_tls_writev
);
595 s
->tls_session
= tls_session
;
596 s
->tls_handshake
= gnutls_handshake(tls_session
);
597 if (s
->tls_handshake
< 0 && gnutls_error_is_fatal(s
->tls_handshake
))
598 return -ECONNREFUSED
;
604 int dns_stream_write_packet(DnsStream
*s
, DnsPacket
*p
) {
609 r
= ordered_set_put(s
->write_queue
, p
);
615 return dns_stream_update_io(s
);