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 static void dns_stream_stop(DnsStream
*s
) {
17 s
->io_event_source
= sd_event_source_unref(s
->io_event_source
);
18 s
->timeout_event_source
= sd_event_source_unref(s
->timeout_event_source
);
19 s
->fd
= safe_close(s
->fd
);
21 /* Disconnect us from the server object if we are now not usable anymore */
25 static int dns_stream_update_io(DnsStream
*s
) {
30 if (s
->write_packet
&& s
->n_written
< sizeof(s
->write_size
) + s
->write_packet
->size
)
32 else if (!ordered_set_isempty(s
->write_queue
)) {
33 dns_packet_unref(s
->write_packet
);
34 s
->write_packet
= ordered_set_steal_first(s
->write_queue
);
35 s
->write_size
= htobe16(s
->write_packet
->size
);
39 if (!s
->read_packet
|| s
->n_read
< sizeof(s
->read_size
) + s
->read_packet
->size
)
42 #if ENABLE_DNS_OVER_TLS
43 /* For handshake and clean closing purposes, TLS can override requested events */
48 return sd_event_source_set_io_events(s
->io_event_source
, f
);
51 static int dns_stream_complete(DnsStream
*s
, int error
) {
52 _cleanup_(dns_stream_unrefp
) _unused_ DnsStream
*ref
= dns_stream_ref(s
); /* Protect stream while we process it */
56 #if ENABLE_DNS_OVER_TLS
60 r
= dnstls_stream_shutdown(s
, error
);
70 s
->complete(s
, error
);
71 else /* the default action if no completion function is set is to close the stream */
77 static int dns_stream_identify(DnsStream
*s
) {
79 struct cmsghdr header
; /* For alignment */
80 uint8_t buffer
[CMSG_SPACE(MAXSIZE(struct in_pktinfo
, struct in6_pktinfo
))
81 + EXTRA_CMSG_SPACE
/* kernel appears to require extra space */];
83 struct msghdr mh
= {};
93 /* Query the local side */
94 s
->local_salen
= sizeof(s
->local
);
95 r
= getsockname(s
->fd
, &s
->local
.sa
, &s
->local_salen
);
98 if (s
->local
.sa
.sa_family
== AF_INET6
&& s
->ifindex
<= 0)
99 s
->ifindex
= s
->local
.in6
.sin6_scope_id
;
101 /* Query the remote side */
102 s
->peer_salen
= sizeof(s
->peer
);
103 r
= getpeername(s
->fd
, &s
->peer
.sa
, &s
->peer_salen
);
106 if (s
->peer
.sa
.sa_family
== AF_INET6
&& s
->ifindex
<= 0)
107 s
->ifindex
= s
->peer
.in6
.sin6_scope_id
;
109 /* Check consistency */
110 assert(s
->peer
.sa
.sa_family
== s
->local
.sa
.sa_family
);
111 assert(IN_SET(s
->peer
.sa
.sa_family
, AF_INET
, AF_INET6
));
113 /* Query connection meta information */
114 sl
= sizeof(control
);
115 if (s
->peer
.sa
.sa_family
== AF_INET
) {
116 r
= getsockopt(s
->fd
, IPPROTO_IP
, IP_PKTOPTIONS
, &control
, &sl
);
119 } else if (s
->peer
.sa
.sa_family
== AF_INET6
) {
121 r
= getsockopt(s
->fd
, IPPROTO_IPV6
, IPV6_2292PKTOPTIONS
, &control
, &sl
);
125 return -EAFNOSUPPORT
;
127 mh
.msg_control
= &control
;
128 mh
.msg_controllen
= sl
;
130 CMSG_FOREACH(cmsg
, &mh
) {
132 if (cmsg
->cmsg_level
== IPPROTO_IPV6
) {
133 assert(s
->peer
.sa
.sa_family
== AF_INET6
);
135 switch (cmsg
->cmsg_type
) {
138 struct in6_pktinfo
*i
= (struct in6_pktinfo
*) CMSG_DATA(cmsg
);
141 s
->ifindex
= i
->ipi6_ifindex
;
146 s
->ttl
= *(int *) CMSG_DATA(cmsg
);
150 } else if (cmsg
->cmsg_level
== IPPROTO_IP
) {
151 assert(s
->peer
.sa
.sa_family
== AF_INET
);
153 switch (cmsg
->cmsg_type
) {
156 struct in_pktinfo
*i
= (struct in_pktinfo
*) CMSG_DATA(cmsg
);
159 s
->ifindex
= i
->ipi_ifindex
;
164 s
->ttl
= *(int *) CMSG_DATA(cmsg
);
170 /* The Linux kernel sets the interface index to the loopback
171 * device if the connection came from the local host since it
172 * avoids the routing table in such a case. Let's unset the
173 * interface index in such a case. */
174 if (s
->ifindex
== LOOPBACK_IFINDEX
)
177 /* If we don't know the interface index still, we look for the
178 * first local interface with a matching address. Yuck! */
180 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
);
182 if (s
->protocol
== DNS_PROTOCOL_LLMNR
&& s
->ifindex
> 0) {
183 uint32_t ifindex
= htobe32(s
->ifindex
);
185 /* Make sure all packets for this connection are sent on the same interface */
186 if (s
->local
.sa
.sa_family
== AF_INET
) {
187 r
= setsockopt(s
->fd
, IPPROTO_IP
, IP_UNICAST_IF
, &ifindex
, sizeof(ifindex
));
189 log_debug_errno(errno
, "Failed to invoke IP_UNICAST_IF: %m");
190 } else if (s
->local
.sa
.sa_family
== AF_INET6
) {
191 r
= setsockopt(s
->fd
, IPPROTO_IPV6
, IPV6_UNICAST_IF
, &ifindex
, sizeof(ifindex
));
193 log_debug_errno(errno
, "Failed to invoke IPV6_UNICAST_IF: %m");
197 s
->identified
= true;
202 ssize_t
dns_stream_writev(DnsStream
*s
, const struct iovec
*iov
, size_t iovcnt
, int flags
) {
208 #if ENABLE_DNS_OVER_TLS
209 if (s
->encrypted
&& !(flags
& DNS_STREAM_WRITE_TLS_DATA
)) {
214 for (i
= 0; i
< iovcnt
; i
++) {
215 ss
= dnstls_stream_write(s
, iov
[i
].iov_base
, iov
[i
].iov_len
);
220 if (ss
!= (ssize_t
) iov
[i
].iov_len
)
225 if (s
->tfo_salen
> 0) {
226 struct msghdr hdr
= {
227 .msg_iov
= (struct iovec
*) iov
,
228 .msg_iovlen
= iovcnt
,
229 .msg_name
= &s
->tfo_address
.sa
,
230 .msg_namelen
= s
->tfo_salen
233 m
= sendmsg(s
->fd
, &hdr
, MSG_FASTOPEN
);
235 if (errno
== EOPNOTSUPP
) {
237 if (connect(s
->fd
, &s
->tfo_address
.sa
, s
->tfo_salen
) < 0)
242 if (errno
== EINPROGRESS
)
247 s
->tfo_salen
= 0; /* connection is made */
249 m
= writev(s
->fd
, iov
, iovcnt
);
257 static ssize_t
dns_stream_read(DnsStream
*s
, void *buf
, size_t count
) {
260 #if ENABLE_DNS_OVER_TLS
262 ss
= dnstls_stream_read(s
, buf
, count
);
266 ss
= read(s
->fd
, buf
, count
);
274 static int on_stream_timeout(sd_event_source
*es
, usec_t usec
, void *userdata
) {
275 DnsStream
*s
= userdata
;
279 return dns_stream_complete(s
, ETIMEDOUT
);
282 static int on_stream_io(sd_event_source
*es
, int fd
, uint32_t revents
, void *userdata
) {
283 _cleanup_(dns_stream_unrefp
) DnsStream
*s
= dns_stream_ref(userdata
); /* Protect stream while we process it */
288 #if ENABLE_DNS_OVER_TLS
290 r
= dnstls_stream_on_io(s
, revents
);
291 if (r
== DNSTLS_STREAM_CLOSED
)
294 return dns_stream_update_io(s
);
296 return dns_stream_complete(s
, -r
);
298 r
= dns_stream_update_io(s
);
304 /* only identify after connecting */
305 if (s
->tfo_salen
== 0) {
306 r
= dns_stream_identify(s
);
308 return dns_stream_complete(s
, -r
);
311 if ((revents
& EPOLLOUT
) &&
313 s
->n_written
< sizeof(s
->write_size
) + s
->write_packet
->size
) {
318 iov
[0] = IOVEC_MAKE(&s
->write_size
, sizeof(s
->write_size
));
319 iov
[1] = IOVEC_MAKE(DNS_PACKET_DATA(s
->write_packet
), s
->write_packet
->size
);
321 IOVEC_INCREMENT(iov
, 2, s
->n_written
);
323 ss
= dns_stream_writev(s
, iov
, 2, 0);
325 if (!IN_SET(-ss
, EINTR
, EAGAIN
))
326 return dns_stream_complete(s
, -ss
);
330 /* Are we done? If so, disable the event source for EPOLLOUT */
331 if (s
->n_written
>= sizeof(s
->write_size
) + s
->write_packet
->size
) {
332 r
= dns_stream_update_io(s
);
334 return dns_stream_complete(s
, -r
);
338 if ((revents
& (EPOLLIN
|EPOLLHUP
|EPOLLRDHUP
)) &&
340 s
->n_read
< sizeof(s
->read_size
) + s
->read_packet
->size
)) {
342 if (s
->n_read
< sizeof(s
->read_size
)) {
345 ss
= dns_stream_read(s
, (uint8_t*) &s
->read_size
+ s
->n_read
, sizeof(s
->read_size
) - s
->n_read
);
347 if (!IN_SET(-ss
, EINTR
, EAGAIN
))
348 return dns_stream_complete(s
, -ss
);
350 return dns_stream_complete(s
, ECONNRESET
);
355 if (s
->n_read
>= sizeof(s
->read_size
)) {
357 if (be16toh(s
->read_size
) < DNS_PACKET_HEADER_SIZE
)
358 return dns_stream_complete(s
, EBADMSG
);
360 if (s
->n_read
< sizeof(s
->read_size
) + be16toh(s
->read_size
)) {
363 if (!s
->read_packet
) {
364 r
= dns_packet_new(&s
->read_packet
, s
->protocol
, be16toh(s
->read_size
), DNS_PACKET_SIZE_MAX
);
366 return dns_stream_complete(s
, -r
);
368 s
->read_packet
->size
= be16toh(s
->read_size
);
369 s
->read_packet
->ipproto
= IPPROTO_TCP
;
370 s
->read_packet
->family
= s
->peer
.sa
.sa_family
;
371 s
->read_packet
->ttl
= s
->ttl
;
372 s
->read_packet
->ifindex
= s
->ifindex
;
374 if (s
->read_packet
->family
== AF_INET
) {
375 s
->read_packet
->sender
.in
= s
->peer
.in
.sin_addr
;
376 s
->read_packet
->sender_port
= be16toh(s
->peer
.in
.sin_port
);
377 s
->read_packet
->destination
.in
= s
->local
.in
.sin_addr
;
378 s
->read_packet
->destination_port
= be16toh(s
->local
.in
.sin_port
);
380 assert(s
->read_packet
->family
== AF_INET6
);
381 s
->read_packet
->sender
.in6
= s
->peer
.in6
.sin6_addr
;
382 s
->read_packet
->sender_port
= be16toh(s
->peer
.in6
.sin6_port
);
383 s
->read_packet
->destination
.in6
= s
->local
.in6
.sin6_addr
;
384 s
->read_packet
->destination_port
= be16toh(s
->local
.in6
.sin6_port
);
386 if (s
->read_packet
->ifindex
== 0)
387 s
->read_packet
->ifindex
= s
->peer
.in6
.sin6_scope_id
;
388 if (s
->read_packet
->ifindex
== 0)
389 s
->read_packet
->ifindex
= s
->local
.in6
.sin6_scope_id
;
393 ss
= dns_stream_read(s
,
394 (uint8_t*) DNS_PACKET_DATA(s
->read_packet
) + s
->n_read
- sizeof(s
->read_size
),
395 sizeof(s
->read_size
) + be16toh(s
->read_size
) - s
->n_read
);
397 if (!IN_SET(-ss
, EINTR
, EAGAIN
))
398 return dns_stream_complete(s
, -ss
);
400 return dns_stream_complete(s
, ECONNRESET
);
405 /* Are we done? If so, disable the event source for EPOLLIN */
406 if (s
->n_read
>= sizeof(s
->read_size
) + be16toh(s
->read_size
)) {
407 /* If there's a packet handler
408 * installed, call that. Note that
409 * this is optional... */
416 r
= dns_stream_update_io(s
);
418 return dns_stream_complete(s
, -r
);
423 if ((s
->write_packet
&& s
->n_written
>= sizeof(s
->write_size
) + s
->write_packet
->size
) &&
424 (s
->read_packet
&& s
->n_read
>= sizeof(s
->read_size
) + s
->read_packet
->size
))
425 return dns_stream_complete(s
, 0);
430 static DnsStream
*dns_stream_free(DnsStream
*s
) {
439 LIST_REMOVE(streams
, s
->manager
->dns_streams
, s
);
440 s
->manager
->n_dns_streams
--;
443 #if ENABLE_DNS_OVER_TLS
445 dnstls_stream_free(s
);
448 ORDERED_SET_FOREACH(p
, s
->write_queue
, i
)
449 dns_packet_unref(ordered_set_remove(s
->write_queue
, p
));
451 dns_packet_unref(s
->write_packet
);
452 dns_packet_unref(s
->read_packet
);
453 dns_server_unref(s
->server
);
455 ordered_set_free(s
->write_queue
);
460 DEFINE_TRIVIAL_REF_UNREF_FUNC(DnsStream
, dns_stream
, dns_stream_free
);
465 DnsProtocol protocol
,
467 const union sockaddr_union
*tfo_address
) {
469 _cleanup_(dns_stream_unrefp
) DnsStream
*s
= NULL
;
476 if (m
->n_dns_streams
> DNS_STREAMS_MAX
)
479 s
= new(DnsStream
, 1);
486 .protocol
= protocol
,
489 r
= ordered_set_ensure_allocated(&s
->write_queue
, &dns_packet_hash_ops
);
493 r
= sd_event_add_io(m
->event
, &s
->io_event_source
, fd
, EPOLLIN
, on_stream_io
, s
);
497 (void) sd_event_source_set_description(s
->io_event_source
, "dns-stream-io");
499 r
= sd_event_add_time(
501 &s
->timeout_event_source
,
502 clock_boottime_or_monotonic(),
503 now(clock_boottime_or_monotonic()) + DNS_STREAM_TIMEOUT_USEC
, 0,
504 on_stream_timeout
, s
);
508 (void) sd_event_source_set_description(s
->timeout_event_source
, "dns-stream-timeout");
510 LIST_PREPEND(streams
, m
->dns_streams
, s
);
517 s
->tfo_address
= *tfo_address
;
518 s
->tfo_salen
= tfo_address
->sa
.sa_family
== AF_INET6
? sizeof(tfo_address
->in6
) : sizeof(tfo_address
->in
);
526 int dns_stream_write_packet(DnsStream
*s
, DnsPacket
*p
) {
532 r
= ordered_set_put(s
->write_queue
, p
);
538 return dns_stream_update_io(s
);
541 DnsPacket
*dns_stream_take_read_packet(DnsStream
*s
) {
547 if (s
->n_read
< sizeof(s
->read_size
))
550 if (s
->n_read
< sizeof(s
->read_size
) + be16toh(s
->read_size
))
554 return TAKE_PTR(s
->read_packet
);
557 void dns_stream_detach(DnsStream
*s
) {
563 if (s
->server
->stream
!= s
)
566 dns_server_unref_stream(s
->server
);