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
);
22 static int dns_stream_update_io(DnsStream
*s
) {
27 if (s
->write_packet
&& s
->n_written
< sizeof(s
->write_size
) + s
->write_packet
->size
)
29 else if (!ordered_set_isempty(s
->write_queue
)) {
30 dns_packet_unref(s
->write_packet
);
31 s
->write_packet
= ordered_set_steal_first(s
->write_queue
);
32 s
->write_size
= htobe16(s
->write_packet
->size
);
36 if (!s
->read_packet
|| s
->n_read
< sizeof(s
->read_size
) + s
->read_packet
->size
)
39 #if ENABLE_DNS_OVER_TLS
40 /* For handshake and clean closing purposes, TLS can override requested events */
45 return sd_event_source_set_io_events(s
->io_event_source
, f
);
48 static int dns_stream_complete(DnsStream
*s
, int error
) {
51 #if ENABLE_DNS_OVER_TLS
55 r
= dnstls_stream_shutdown(s
, error
);
63 s
->complete(s
, error
);
64 else /* the default action if no completion function is set is to close the stream */
70 static int dns_stream_identify(DnsStream
*s
) {
72 struct cmsghdr header
; /* For alignment */
73 uint8_t buffer
[CMSG_SPACE(MAXSIZE(struct in_pktinfo
, struct in6_pktinfo
))
74 + EXTRA_CMSG_SPACE
/* kernel appears to require extra space */];
76 struct msghdr mh
= {};
86 /* Query the local side */
87 s
->local_salen
= sizeof(s
->local
);
88 r
= getsockname(s
->fd
, &s
->local
.sa
, &s
->local_salen
);
91 if (s
->local
.sa
.sa_family
== AF_INET6
&& s
->ifindex
<= 0)
92 s
->ifindex
= s
->local
.in6
.sin6_scope_id
;
94 /* Query the remote side */
95 s
->peer_salen
= sizeof(s
->peer
);
96 r
= getpeername(s
->fd
, &s
->peer
.sa
, &s
->peer_salen
);
99 if (s
->peer
.sa
.sa_family
== AF_INET6
&& s
->ifindex
<= 0)
100 s
->ifindex
= s
->peer
.in6
.sin6_scope_id
;
102 /* Check consistency */
103 assert(s
->peer
.sa
.sa_family
== s
->local
.sa
.sa_family
);
104 assert(IN_SET(s
->peer
.sa
.sa_family
, AF_INET
, AF_INET6
));
106 /* Query connection meta information */
107 sl
= sizeof(control
);
108 if (s
->peer
.sa
.sa_family
== AF_INET
) {
109 r
= getsockopt(s
->fd
, IPPROTO_IP
, IP_PKTOPTIONS
, &control
, &sl
);
112 } else if (s
->peer
.sa
.sa_family
== AF_INET6
) {
114 r
= getsockopt(s
->fd
, IPPROTO_IPV6
, IPV6_2292PKTOPTIONS
, &control
, &sl
);
118 return -EAFNOSUPPORT
;
120 mh
.msg_control
= &control
;
121 mh
.msg_controllen
= sl
;
123 CMSG_FOREACH(cmsg
, &mh
) {
125 if (cmsg
->cmsg_level
== IPPROTO_IPV6
) {
126 assert(s
->peer
.sa
.sa_family
== AF_INET6
);
128 switch (cmsg
->cmsg_type
) {
131 struct in6_pktinfo
*i
= (struct in6_pktinfo
*) CMSG_DATA(cmsg
);
134 s
->ifindex
= i
->ipi6_ifindex
;
139 s
->ttl
= *(int *) CMSG_DATA(cmsg
);
143 } else if (cmsg
->cmsg_level
== IPPROTO_IP
) {
144 assert(s
->peer
.sa
.sa_family
== AF_INET
);
146 switch (cmsg
->cmsg_type
) {
149 struct in_pktinfo
*i
= (struct in_pktinfo
*) CMSG_DATA(cmsg
);
152 s
->ifindex
= i
->ipi_ifindex
;
157 s
->ttl
= *(int *) CMSG_DATA(cmsg
);
163 /* The Linux kernel sets the interface index to the loopback
164 * device if the connection came from the local host since it
165 * avoids the routing table in such a case. Let's unset the
166 * interface index in such a case. */
167 if (s
->ifindex
== LOOPBACK_IFINDEX
)
170 /* If we don't know the interface index still, we look for the
171 * first local interface with a matching address. Yuck! */
173 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
);
175 if (s
->protocol
== DNS_PROTOCOL_LLMNR
&& s
->ifindex
> 0) {
176 uint32_t ifindex
= htobe32(s
->ifindex
);
178 /* Make sure all packets for this connection are sent on the same interface */
179 if (s
->local
.sa
.sa_family
== AF_INET
) {
180 r
= setsockopt(s
->fd
, IPPROTO_IP
, IP_UNICAST_IF
, &ifindex
, sizeof(ifindex
));
182 log_debug_errno(errno
, "Failed to invoke IP_UNICAST_IF: %m");
183 } else if (s
->local
.sa
.sa_family
== AF_INET6
) {
184 r
= setsockopt(s
->fd
, IPPROTO_IPV6
, IPV6_UNICAST_IF
, &ifindex
, sizeof(ifindex
));
186 log_debug_errno(errno
, "Failed to invoke IPV6_UNICAST_IF: %m");
190 s
->identified
= true;
195 ssize_t
dns_stream_writev(DnsStream
*s
, const struct iovec
*iov
, size_t iovcnt
, int flags
) {
201 #if ENABLE_DNS_OVER_TLS
202 if (s
->encrypted
&& !(flags
& DNS_STREAM_WRITE_TLS_DATA
)) {
207 for (i
= 0; i
< iovcnt
; i
++) {
208 ss
= dnstls_stream_write(s
, iov
[i
].iov_base
, iov
[i
].iov_len
);
213 if (ss
!= (ssize_t
) iov
[i
].iov_len
)
218 if (s
->tfo_salen
> 0) {
219 struct msghdr hdr
= {
220 .msg_iov
= (struct iovec
*) iov
,
221 .msg_iovlen
= iovcnt
,
222 .msg_name
= &s
->tfo_address
.sa
,
223 .msg_namelen
= s
->tfo_salen
226 r
= sendmsg(s
->fd
, &hdr
, MSG_FASTOPEN
);
228 if (errno
== EOPNOTSUPP
) {
230 r
= connect(s
->fd
, &s
->tfo_address
.sa
, s
->tfo_salen
);
235 } else if (errno
== EINPROGRESS
)
240 s
->tfo_salen
= 0; /* connection is made */
242 r
= writev(s
->fd
, iov
, iovcnt
);
250 static ssize_t
dns_stream_read(DnsStream
*s
, void *buf
, size_t count
) {
253 #if ENABLE_DNS_OVER_TLS
255 ss
= dnstls_stream_read(s
, buf
, count
);
259 ss
= read(s
->fd
, buf
, count
);
267 static int on_stream_timeout(sd_event_source
*es
, usec_t usec
, void *userdata
) {
268 DnsStream
*s
= userdata
;
272 return dns_stream_complete(s
, ETIMEDOUT
);
275 static int on_stream_io(sd_event_source
*es
, int fd
, uint32_t revents
, void *userdata
) {
276 DnsStream
*s
= userdata
;
281 #if ENABLE_DNS_OVER_TLS
283 r
= dnstls_stream_on_io(s
, revents
);
285 if (r
== DNSTLS_STREAM_CLOSED
)
287 else if (r
== -EAGAIN
)
288 return dns_stream_update_io(s
);
290 return dns_stream_complete(s
, -r
);
292 r
= dns_stream_update_io(s
);
299 /* only identify after connecting */
300 if (s
->tfo_salen
== 0) {
301 r
= dns_stream_identify(s
);
303 return dns_stream_complete(s
, -r
);
306 if ((revents
& EPOLLOUT
) &&
308 s
->n_written
< sizeof(s
->write_size
) + s
->write_packet
->size
) {
313 iov
[0].iov_base
= &s
->write_size
;
314 iov
[0].iov_len
= sizeof(s
->write_size
);
315 iov
[1].iov_base
= DNS_PACKET_DATA(s
->write_packet
);
316 iov
[1].iov_len
= s
->write_packet
->size
;
318 IOVEC_INCREMENT(iov
, 2, s
->n_written
);
320 ss
= dns_stream_writev(s
, iov
, 2, 0);
322 if (!IN_SET(-ss
, EINTR
, EAGAIN
))
323 return dns_stream_complete(s
, -ss
);
327 /* Are we done? If so, disable the event source for EPOLLOUT */
328 if (s
->n_written
>= sizeof(s
->write_size
) + s
->write_packet
->size
) {
329 r
= dns_stream_update_io(s
);
331 return dns_stream_complete(s
, -r
);
335 if ((revents
& (EPOLLIN
|EPOLLHUP
|EPOLLRDHUP
)) &&
337 s
->n_read
< sizeof(s
->read_size
) + s
->read_packet
->size
)) {
339 if (s
->n_read
< sizeof(s
->read_size
)) {
342 ss
= dns_stream_read(s
, (uint8_t*) &s
->read_size
+ s
->n_read
, sizeof(s
->read_size
) - s
->n_read
);
344 if (!IN_SET(-ss
, EINTR
, EAGAIN
))
345 return dns_stream_complete(s
, -ss
);
347 return dns_stream_complete(s
, ECONNRESET
);
352 if (s
->n_read
>= sizeof(s
->read_size
)) {
354 if (be16toh(s
->read_size
) < DNS_PACKET_HEADER_SIZE
)
355 return dns_stream_complete(s
, EBADMSG
);
357 if (s
->n_read
< sizeof(s
->read_size
) + be16toh(s
->read_size
)) {
360 if (!s
->read_packet
) {
361 r
= dns_packet_new(&s
->read_packet
, s
->protocol
, be16toh(s
->read_size
), DNS_PACKET_SIZE_MAX
);
363 return dns_stream_complete(s
, -r
);
365 s
->read_packet
->size
= be16toh(s
->read_size
);
366 s
->read_packet
->ipproto
= IPPROTO_TCP
;
367 s
->read_packet
->family
= s
->peer
.sa
.sa_family
;
368 s
->read_packet
->ttl
= s
->ttl
;
369 s
->read_packet
->ifindex
= s
->ifindex
;
371 if (s
->read_packet
->family
== AF_INET
) {
372 s
->read_packet
->sender
.in
= s
->peer
.in
.sin_addr
;
373 s
->read_packet
->sender_port
= be16toh(s
->peer
.in
.sin_port
);
374 s
->read_packet
->destination
.in
= s
->local
.in
.sin_addr
;
375 s
->read_packet
->destination_port
= be16toh(s
->local
.in
.sin_port
);
377 assert(s
->read_packet
->family
== AF_INET6
);
378 s
->read_packet
->sender
.in6
= s
->peer
.in6
.sin6_addr
;
379 s
->read_packet
->sender_port
= be16toh(s
->peer
.in6
.sin6_port
);
380 s
->read_packet
->destination
.in6
= s
->local
.in6
.sin6_addr
;
381 s
->read_packet
->destination_port
= be16toh(s
->local
.in6
.sin6_port
);
383 if (s
->read_packet
->ifindex
== 0)
384 s
->read_packet
->ifindex
= s
->peer
.in6
.sin6_scope_id
;
385 if (s
->read_packet
->ifindex
== 0)
386 s
->read_packet
->ifindex
= s
->local
.in6
.sin6_scope_id
;
390 ss
= dns_stream_read(s
,
391 (uint8_t*) DNS_PACKET_DATA(s
->read_packet
) + s
->n_read
- sizeof(s
->read_size
),
392 sizeof(s
->read_size
) + be16toh(s
->read_size
) - s
->n_read
);
394 if (!IN_SET(-ss
, EINTR
, EAGAIN
))
395 return dns_stream_complete(s
, -ss
);
397 return dns_stream_complete(s
, ECONNRESET
);
402 /* Are we done? If so, disable the event source for EPOLLIN */
403 if (s
->n_read
>= sizeof(s
->read_size
) + be16toh(s
->read_size
)) {
404 /* If there's a packet handler
405 * installed, call that. Note that
406 * this is optional... */
413 r
= dns_stream_update_io(s
);
415 return dns_stream_complete(s
, -r
);
420 if ((s
->write_packet
&& s
->n_written
>= sizeof(s
->write_size
) + s
->write_packet
->size
) &&
421 (s
->read_packet
&& s
->n_read
>= sizeof(s
->read_size
) + s
->read_packet
->size
))
422 return dns_stream_complete(s
, 0);
427 DnsStream
*dns_stream_unref(DnsStream
*s
) {
434 assert(s
->n_ref
> 0);
442 if (s
->server
&& s
->server
->stream
== s
)
443 s
->server
->stream
= NULL
;
446 LIST_REMOVE(streams
, s
->manager
->dns_streams
, s
);
447 s
->manager
->n_dns_streams
--;
450 #if ENABLE_DNS_OVER_TLS
452 dnstls_stream_free(s
);
455 ORDERED_SET_FOREACH(p
, s
->write_queue
, i
)
456 dns_packet_unref(ordered_set_remove(s
->write_queue
, p
));
458 dns_packet_unref(s
->write_packet
);
459 dns_packet_unref(s
->read_packet
);
460 dns_server_unref(s
->server
);
462 ordered_set_free(s
->write_queue
);
467 DnsStream
*dns_stream_ref(DnsStream
*s
) {
471 assert(s
->n_ref
> 0);
477 int dns_stream_new(Manager
*m
, DnsStream
**ret
, DnsProtocol protocol
, int fd
, const union sockaddr_union
*tfo_address
) {
478 _cleanup_(dns_stream_unrefp
) DnsStream
*s
= NULL
;
484 if (m
->n_dns_streams
> DNS_STREAMS_MAX
)
487 s
= new0(DnsStream
, 1);
491 r
= ordered_set_ensure_allocated(&s
->write_queue
, &dns_packet_hash_ops
);
497 s
->protocol
= protocol
;
499 r
= sd_event_add_io(m
->event
, &s
->io_event_source
, fd
, EPOLLIN
, on_stream_io
, s
);
503 (void) sd_event_source_set_description(s
->io_event_source
, "dns-stream-io");
505 r
= sd_event_add_time(
507 &s
->timeout_event_source
,
508 clock_boottime_or_monotonic(),
509 now(clock_boottime_or_monotonic()) + DNS_STREAM_TIMEOUT_USEC
, 0,
510 on_stream_timeout
, s
);
514 (void) sd_event_source_set_description(s
->timeout_event_source
, "dns-stream-timeout");
516 LIST_PREPEND(streams
, m
->dns_streams
, s
);
520 s
->tfo_address
= *tfo_address
;
521 s
->tfo_salen
= tfo_address
->sa
.sa_family
== AF_INET6
? sizeof(tfo_address
->in6
) : sizeof(tfo_address
->in
);
531 int dns_stream_write_packet(DnsStream
*s
, DnsPacket
*p
) {
536 r
= ordered_set_put(s
->write_queue
, p
);
542 return dns_stream_update_io(s
);