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 DNS_QUERIES_PER_STREAM 32
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
);
23 /* Disconnect us from the server object if we are now not usable anymore */
27 static int dns_stream_update_io(DnsStream
*s
) {
32 if (s
->write_packet
&& s
->n_written
< sizeof(s
->write_size
) + s
->write_packet
->size
)
34 else if (!ordered_set_isempty(s
->write_queue
)) {
35 dns_packet_unref(s
->write_packet
);
36 s
->write_packet
= ordered_set_steal_first(s
->write_queue
);
37 s
->write_size
= htobe16(s
->write_packet
->size
);
42 /* Let's read a packet if we haven't queued any yet. Except if we already hit a limit of parallel
43 * queries for this connection. */
44 if ((!s
->read_packet
|| s
->n_read
< sizeof(s
->read_size
) + s
->read_packet
->size
) &&
45 set_size(s
->queries
) < DNS_QUERIES_PER_STREAM
)
48 #if ENABLE_DNS_OVER_TLS
49 /* For handshake and clean closing purposes, TLS can override requested events */
50 if (s
->dnstls_events
!= 0)
54 return sd_event_source_set_io_events(s
->io_event_source
, f
);
57 static int dns_stream_complete(DnsStream
*s
, int error
) {
58 _cleanup_(dns_stream_unrefp
) _unused_ DnsStream
*ref
= dns_stream_ref(s
); /* Protect stream while we process it */
63 /* Error is > 0 when the connection failed for some reason in the network stack. It's == 0 if we sent
64 * and received exactly one packet each (in the LLMNR client case). */
66 #if ENABLE_DNS_OVER_TLS
70 r
= dnstls_stream_shutdown(s
, error
);
80 s
->complete(s
, error
);
81 else /* the default action if no completion function is set is to close the stream */
87 static int dns_stream_identify(DnsStream
*s
) {
89 struct cmsghdr header
; /* For alignment */
90 uint8_t buffer
[CMSG_SPACE(MAXSIZE(struct in_pktinfo
, struct in6_pktinfo
))
91 + EXTRA_CMSG_SPACE
/* kernel appears to require extra space */];
93 struct msghdr mh
= {};
103 /* Query the local side */
104 s
->local_salen
= sizeof(s
->local
);
105 r
= getsockname(s
->fd
, &s
->local
.sa
, &s
->local_salen
);
108 if (s
->local
.sa
.sa_family
== AF_INET6
&& s
->ifindex
<= 0)
109 s
->ifindex
= s
->local
.in6
.sin6_scope_id
;
111 /* Query the remote side */
112 s
->peer_salen
= sizeof(s
->peer
);
113 r
= getpeername(s
->fd
, &s
->peer
.sa
, &s
->peer_salen
);
116 if (s
->peer
.sa
.sa_family
== AF_INET6
&& s
->ifindex
<= 0)
117 s
->ifindex
= s
->peer
.in6
.sin6_scope_id
;
119 /* Check consistency */
120 assert(s
->peer
.sa
.sa_family
== s
->local
.sa
.sa_family
);
121 assert(IN_SET(s
->peer
.sa
.sa_family
, AF_INET
, AF_INET6
));
123 /* Query connection meta information */
124 sl
= sizeof(control
);
125 if (s
->peer
.sa
.sa_family
== AF_INET
) {
126 r
= getsockopt(s
->fd
, IPPROTO_IP
, IP_PKTOPTIONS
, &control
, &sl
);
129 } else if (s
->peer
.sa
.sa_family
== AF_INET6
) {
131 r
= getsockopt(s
->fd
, IPPROTO_IPV6
, IPV6_2292PKTOPTIONS
, &control
, &sl
);
135 return -EAFNOSUPPORT
;
137 mh
.msg_control
= &control
;
138 mh
.msg_controllen
= sl
;
140 CMSG_FOREACH(cmsg
, &mh
) {
142 if (cmsg
->cmsg_level
== IPPROTO_IPV6
) {
143 assert(s
->peer
.sa
.sa_family
== AF_INET6
);
145 switch (cmsg
->cmsg_type
) {
148 struct in6_pktinfo
*i
= (struct in6_pktinfo
*) CMSG_DATA(cmsg
);
151 s
->ifindex
= i
->ipi6_ifindex
;
156 s
->ttl
= *(int *) CMSG_DATA(cmsg
);
160 } else if (cmsg
->cmsg_level
== IPPROTO_IP
) {
161 assert(s
->peer
.sa
.sa_family
== AF_INET
);
163 switch (cmsg
->cmsg_type
) {
166 struct in_pktinfo
*i
= (struct in_pktinfo
*) CMSG_DATA(cmsg
);
169 s
->ifindex
= i
->ipi_ifindex
;
174 s
->ttl
= *(int *) CMSG_DATA(cmsg
);
180 /* The Linux kernel sets the interface index to the loopback
181 * device if the connection came from the local host since it
182 * avoids the routing table in such a case. Let's unset the
183 * interface index in such a case. */
184 if (s
->ifindex
== LOOPBACK_IFINDEX
)
187 /* If we don't know the interface index still, we look for the
188 * first local interface with a matching address. Yuck! */
190 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
);
192 if (s
->protocol
== DNS_PROTOCOL_LLMNR
&& s
->ifindex
> 0) {
193 uint32_t ifindex
= htobe32(s
->ifindex
);
195 /* Make sure all packets for this connection are sent on the same interface */
196 if (s
->local
.sa
.sa_family
== AF_INET
) {
197 r
= setsockopt(s
->fd
, IPPROTO_IP
, IP_UNICAST_IF
, &ifindex
, sizeof(ifindex
));
199 log_debug_errno(errno
, "Failed to invoke IP_UNICAST_IF: %m");
200 } else if (s
->local
.sa
.sa_family
== AF_INET6
) {
201 r
= setsockopt(s
->fd
, IPPROTO_IPV6
, IPV6_UNICAST_IF
, &ifindex
, sizeof(ifindex
));
203 log_debug_errno(errno
, "Failed to invoke IPV6_UNICAST_IF: %m");
207 s
->identified
= true;
212 ssize_t
dns_stream_writev(DnsStream
*s
, const struct iovec
*iov
, size_t iovcnt
, int flags
) {
218 #if ENABLE_DNS_OVER_TLS
219 if (s
->encrypted
&& !(flags
& DNS_STREAM_WRITE_TLS_DATA
)) {
224 for (i
= 0; i
< iovcnt
; i
++) {
225 ss
= dnstls_stream_write(s
, iov
[i
].iov_base
, iov
[i
].iov_len
);
230 if (ss
!= (ssize_t
) iov
[i
].iov_len
)
235 if (s
->tfo_salen
> 0) {
236 struct msghdr hdr
= {
237 .msg_iov
= (struct iovec
*) iov
,
238 .msg_iovlen
= iovcnt
,
239 .msg_name
= &s
->tfo_address
.sa
,
240 .msg_namelen
= s
->tfo_salen
243 m
= sendmsg(s
->fd
, &hdr
, MSG_FASTOPEN
);
245 if (errno
== EOPNOTSUPP
) {
247 if (connect(s
->fd
, &s
->tfo_address
.sa
, s
->tfo_salen
) < 0)
252 if (errno
== EINPROGRESS
)
257 s
->tfo_salen
= 0; /* connection is made */
259 m
= writev(s
->fd
, iov
, iovcnt
);
267 static ssize_t
dns_stream_read(DnsStream
*s
, void *buf
, size_t count
) {
270 #if ENABLE_DNS_OVER_TLS
272 ss
= dnstls_stream_read(s
, buf
, count
);
276 ss
= read(s
->fd
, buf
, count
);
284 static int on_stream_timeout(sd_event_source
*es
, usec_t usec
, void *userdata
) {
285 DnsStream
*s
= userdata
;
289 return dns_stream_complete(s
, ETIMEDOUT
);
292 static int on_stream_io(sd_event_source
*es
, int fd
, uint32_t revents
, void *userdata
) {
293 _cleanup_(dns_stream_unrefp
) DnsStream
*s
= dns_stream_ref(userdata
); /* Protect stream while we process it */
294 bool progressed
= false;
299 #if ENABLE_DNS_OVER_TLS
301 r
= dnstls_stream_on_io(s
, revents
);
302 if (r
== DNSTLS_STREAM_CLOSED
)
305 return dns_stream_update_io(s
);
307 return dns_stream_complete(s
, -r
);
309 r
= dns_stream_update_io(s
);
315 /* only identify after connecting */
316 if (s
->tfo_salen
== 0) {
317 r
= dns_stream_identify(s
);
319 return dns_stream_complete(s
, -r
);
322 if ((revents
& EPOLLOUT
) &&
324 s
->n_written
< sizeof(s
->write_size
) + s
->write_packet
->size
) {
329 iov
[0] = IOVEC_MAKE(&s
->write_size
, sizeof(s
->write_size
));
330 iov
[1] = IOVEC_MAKE(DNS_PACKET_DATA(s
->write_packet
), s
->write_packet
->size
);
332 IOVEC_INCREMENT(iov
, 2, s
->n_written
);
334 ss
= dns_stream_writev(s
, iov
, 2, 0);
336 if (!IN_SET(-ss
, EINTR
, EAGAIN
))
337 return dns_stream_complete(s
, -ss
);
343 /* Are we done? If so, disable the event source for EPOLLOUT */
344 if (s
->n_written
>= sizeof(s
->write_size
) + s
->write_packet
->size
) {
345 r
= dns_stream_update_io(s
);
347 return dns_stream_complete(s
, -r
);
351 if ((revents
& (EPOLLIN
|EPOLLHUP
|EPOLLRDHUP
)) &&
353 s
->n_read
< sizeof(s
->read_size
) + s
->read_packet
->size
)) {
355 if (s
->n_read
< sizeof(s
->read_size
)) {
358 ss
= dns_stream_read(s
, (uint8_t*) &s
->read_size
+ s
->n_read
, sizeof(s
->read_size
) - s
->n_read
);
360 if (!IN_SET(-ss
, EINTR
, EAGAIN
))
361 return dns_stream_complete(s
, -ss
);
363 return dns_stream_complete(s
, ECONNRESET
);
370 if (s
->n_read
>= sizeof(s
->read_size
)) {
372 if (be16toh(s
->read_size
) < DNS_PACKET_HEADER_SIZE
)
373 return dns_stream_complete(s
, EBADMSG
);
375 if (s
->n_read
< sizeof(s
->read_size
) + be16toh(s
->read_size
)) {
378 if (!s
->read_packet
) {
379 r
= dns_packet_new(&s
->read_packet
, s
->protocol
, be16toh(s
->read_size
), DNS_PACKET_SIZE_MAX
);
381 return dns_stream_complete(s
, -r
);
383 s
->read_packet
->size
= be16toh(s
->read_size
);
384 s
->read_packet
->ipproto
= IPPROTO_TCP
;
385 s
->read_packet
->family
= s
->peer
.sa
.sa_family
;
386 s
->read_packet
->ttl
= s
->ttl
;
387 s
->read_packet
->ifindex
= s
->ifindex
;
389 if (s
->read_packet
->family
== AF_INET
) {
390 s
->read_packet
->sender
.in
= s
->peer
.in
.sin_addr
;
391 s
->read_packet
->sender_port
= be16toh(s
->peer
.in
.sin_port
);
392 s
->read_packet
->destination
.in
= s
->local
.in
.sin_addr
;
393 s
->read_packet
->destination_port
= be16toh(s
->local
.in
.sin_port
);
395 assert(s
->read_packet
->family
== AF_INET6
);
396 s
->read_packet
->sender
.in6
= s
->peer
.in6
.sin6_addr
;
397 s
->read_packet
->sender_port
= be16toh(s
->peer
.in6
.sin6_port
);
398 s
->read_packet
->destination
.in6
= s
->local
.in6
.sin6_addr
;
399 s
->read_packet
->destination_port
= be16toh(s
->local
.in6
.sin6_port
);
401 if (s
->read_packet
->ifindex
== 0)
402 s
->read_packet
->ifindex
= s
->peer
.in6
.sin6_scope_id
;
403 if (s
->read_packet
->ifindex
== 0)
404 s
->read_packet
->ifindex
= s
->local
.in6
.sin6_scope_id
;
408 ss
= dns_stream_read(s
,
409 (uint8_t*) DNS_PACKET_DATA(s
->read_packet
) + s
->n_read
- sizeof(s
->read_size
),
410 sizeof(s
->read_size
) + be16toh(s
->read_size
) - s
->n_read
);
412 if (!IN_SET(-ss
, EINTR
, EAGAIN
))
413 return dns_stream_complete(s
, -ss
);
415 return dns_stream_complete(s
, ECONNRESET
);
420 /* Are we done? If so, disable the event source for EPOLLIN */
421 if (s
->n_read
>= sizeof(s
->read_size
) + be16toh(s
->read_size
)) {
422 /* If there's a packet handler
423 * installed, call that. Note that
424 * this is optional... */
431 r
= dns_stream_update_io(s
);
433 return dns_stream_complete(s
, -r
);
438 /* Call "complete" callback if finished reading and writing one packet, and there's nothing else left
440 if (s
->type
== DNS_STREAM_LLMNR_SEND
&&
441 (s
->write_packet
&& s
->n_written
>= sizeof(s
->write_size
) + s
->write_packet
->size
) &&
442 ordered_set_isempty(s
->write_queue
) &&
443 (s
->read_packet
&& s
->n_read
>= sizeof(s
->read_size
) + s
->read_packet
->size
))
444 return dns_stream_complete(s
, 0);
446 /* If we did something, let's restart the timeout event source */
447 if (progressed
&& s
->timeout_event_source
) {
448 r
= sd_event_source_set_time(s
->timeout_event_source
, now(clock_boottime_or_monotonic()) + DNS_STREAM_TIMEOUT_USEC
);
450 log_warning_errno(errno
, "Couldn't restart TCP connection timeout, ignoring: %m");
456 static DnsStream
*dns_stream_free(DnsStream
*s
) {
465 LIST_REMOVE(streams
, s
->manager
->dns_streams
, s
);
466 s
->manager
->n_dns_streams
[s
->type
]--;
469 #if ENABLE_DNS_OVER_TLS
471 dnstls_stream_free(s
);
474 ORDERED_SET_FOREACH(p
, s
->write_queue
, i
)
475 dns_packet_unref(ordered_set_remove(s
->write_queue
, p
));
477 dns_packet_unref(s
->write_packet
);
478 dns_packet_unref(s
->read_packet
);
479 dns_server_unref(s
->server
);
481 ordered_set_free(s
->write_queue
);
486 DEFINE_TRIVIAL_REF_UNREF_FUNC(DnsStream
, dns_stream
, dns_stream_free
);
492 DnsProtocol protocol
,
494 const union sockaddr_union
*tfo_address
) {
496 _cleanup_(dns_stream_unrefp
) DnsStream
*s
= NULL
;
502 assert(type
< _DNS_STREAM_TYPE_MAX
);
503 assert(protocol
>= 0);
504 assert(protocol
< _DNS_PROTOCOL_MAX
);
507 if (m
->n_dns_streams
[type
] > DNS_STREAMS_MAX
)
510 s
= new(DnsStream
, 1);
517 .protocol
= protocol
,
521 r
= ordered_set_ensure_allocated(&s
->write_queue
, &dns_packet_hash_ops
);
525 r
= sd_event_add_io(m
->event
, &s
->io_event_source
, fd
, EPOLLIN
, on_stream_io
, s
);
529 (void) sd_event_source_set_description(s
->io_event_source
, "dns-stream-io");
531 r
= sd_event_add_time(
533 &s
->timeout_event_source
,
534 clock_boottime_or_monotonic(),
535 now(clock_boottime_or_monotonic()) + DNS_STREAM_TIMEOUT_USEC
, 0,
536 on_stream_timeout
, s
);
540 (void) sd_event_source_set_description(s
->timeout_event_source
, "dns-stream-timeout");
542 LIST_PREPEND(streams
, m
->dns_streams
, s
);
543 m
->n_dns_streams
[type
]++;
549 s
->tfo_address
= *tfo_address
;
550 s
->tfo_salen
= tfo_address
->sa
.sa_family
== AF_INET6
? sizeof(tfo_address
->in6
) : sizeof(tfo_address
->in
);
558 int dns_stream_write_packet(DnsStream
*s
, DnsPacket
*p
) {
564 r
= ordered_set_put(s
->write_queue
, p
);
570 return dns_stream_update_io(s
);
573 DnsPacket
*dns_stream_take_read_packet(DnsStream
*s
) {
579 if (s
->n_read
< sizeof(s
->read_size
))
582 if (s
->n_read
< sizeof(s
->read_size
) + be16toh(s
->read_size
))
586 return TAKE_PTR(s
->read_packet
);
589 void dns_stream_detach(DnsStream
*s
) {
595 if (s
->server
->stream
!= s
)
598 dns_server_unref_stream(s
->server
);