| /* SPDX-License-Identifier: LGPL-2.1-or-later */ |
| |
| #include <netinet/tcp.h> |
| #include <unistd.h> |
| |
| #include "alloc-util.h" |
| #include "fd-util.h" |
| #include "io-util.h" |
| #include "missing_network.h" |
| #include "resolved-dns-stream.h" |
| #include "resolved-manager.h" |
| |
| #define DNS_STREAM_TIMEOUT_USEC (10 * USEC_PER_SEC) |
| #define DNS_STREAMS_MAX 128 |
| |
| #define DNS_QUERIES_PER_STREAM 32 |
| |
| static void dns_stream_stop(DnsStream *s) { |
| assert(s); |
| |
| s->io_event_source = sd_event_source_disable_unref(s->io_event_source); |
| s->timeout_event_source = sd_event_source_disable_unref(s->timeout_event_source); |
| s->fd = safe_close(s->fd); |
| |
| /* Disconnect us from the server object if we are now not usable anymore */ |
| dns_stream_detach(s); |
| } |
| |
| static int dns_stream_update_io(DnsStream *s) { |
| int f = 0; |
| |
| assert(s); |
| |
| if (s->write_packet && s->n_written < sizeof(s->write_size) + s->write_packet->size) |
| f |= EPOLLOUT; |
| else if (!ordered_set_isempty(s->write_queue)) { |
| dns_packet_unref(s->write_packet); |
| s->write_packet = ordered_set_steal_first(s->write_queue); |
| s->write_size = htobe16(s->write_packet->size); |
| s->n_written = 0; |
| f |= EPOLLOUT; |
| } |
| |
| /* Let's read a packet if we haven't queued any yet. Except if we already hit a limit of parallel |
| * queries for this connection. */ |
| if ((!s->read_packet || s->n_read < sizeof(s->read_size) + s->read_packet->size) && |
| set_size(s->queries) < DNS_QUERIES_PER_STREAM) |
| f |= EPOLLIN; |
| |
| #if ENABLE_DNS_OVER_TLS |
| /* For handshake and clean closing purposes, TLS can override requested events */ |
| if (s->dnstls_events != 0) |
| f = s->dnstls_events; |
| #endif |
| |
| return sd_event_source_set_io_events(s->io_event_source, f); |
| } |
| |
| static int dns_stream_complete(DnsStream *s, int error) { |
| _cleanup_(dns_stream_unrefp) _unused_ DnsStream *ref = dns_stream_ref(s); /* Protect stream while we process it */ |
| |
| assert(s); |
| assert(error >= 0); |
| |
| /* Error is > 0 when the connection failed for some reason in the network stack. It's == 0 if we sent |
| * and received exactly one packet each (in the LLMNR client case). */ |
| |
| #if ENABLE_DNS_OVER_TLS |
| if (s->encrypted) { |
| int r; |
| |
| r = dnstls_stream_shutdown(s, error); |
| if (r != -EAGAIN) |
| dns_stream_stop(s); |
| } else |
| #endif |
| dns_stream_stop(s); |
| |
| dns_stream_detach(s); |
| |
| if (s->complete) |
| s->complete(s, error); |
| else /* the default action if no completion function is set is to close the stream */ |
| dns_stream_unref(s); |
| |
| return 0; |
| } |
| |
| static int dns_stream_identify(DnsStream *s) { |
| CMSG_BUFFER_TYPE(CMSG_SPACE(MAXSIZE(struct in_pktinfo, struct in6_pktinfo)) |
| + CMSG_SPACE(int) + /* for the TTL */ |
| + EXTRA_CMSG_SPACE /* kernel appears to require extra space */) control; |
| struct msghdr mh = {}; |
| struct cmsghdr *cmsg; |
| socklen_t sl; |
| int r; |
| |
| assert(s); |
| |
| if (s->identified) |
| return 0; |
| |
| /* Query the local side */ |
| s->local_salen = sizeof(s->local); |
| r = getsockname(s->fd, &s->local.sa, &s->local_salen); |
| if (r < 0) |
| return -errno; |
| if (s->local.sa.sa_family == AF_INET6 && s->ifindex <= 0) |
| s->ifindex = s->local.in6.sin6_scope_id; |
| |
| /* Query the remote side */ |
| s->peer_salen = sizeof(s->peer); |
| r = getpeername(s->fd, &s->peer.sa, &s->peer_salen); |
| if (r < 0) |
| return -errno; |
| if (s->peer.sa.sa_family == AF_INET6 && s->ifindex <= 0) |
| s->ifindex = s->peer.in6.sin6_scope_id; |
| |
| /* Check consistency */ |
| assert(s->peer.sa.sa_family == s->local.sa.sa_family); |
| assert(IN_SET(s->peer.sa.sa_family, AF_INET, AF_INET6)); |
| |
| /* Query connection meta information */ |
| sl = sizeof(control); |
| if (s->peer.sa.sa_family == AF_INET) { |
| r = getsockopt(s->fd, IPPROTO_IP, IP_PKTOPTIONS, &control, &sl); |
| if (r < 0) |
| return -errno; |
| } else if (s->peer.sa.sa_family == AF_INET6) { |
| |
| r = getsockopt(s->fd, IPPROTO_IPV6, IPV6_2292PKTOPTIONS, &control, &sl); |
| if (r < 0) |
| return -errno; |
| } else |
| return -EAFNOSUPPORT; |
| |
| mh.msg_control = &control; |
| mh.msg_controllen = sl; |
| |
| CMSG_FOREACH(cmsg, &mh) { |
| |
| if (cmsg->cmsg_level == IPPROTO_IPV6) { |
| assert(s->peer.sa.sa_family == AF_INET6); |
| |
| switch (cmsg->cmsg_type) { |
| |
| case IPV6_PKTINFO: { |
| struct in6_pktinfo *i = (struct in6_pktinfo*) CMSG_DATA(cmsg); |
| |
| if (s->ifindex <= 0) |
| s->ifindex = i->ipi6_ifindex; |
| break; |
| } |
| |
| case IPV6_HOPLIMIT: |
| s->ttl = *(int *) CMSG_DATA(cmsg); |
| break; |
| } |
| |
| } else if (cmsg->cmsg_level == IPPROTO_IP) { |
| assert(s->peer.sa.sa_family == AF_INET); |
| |
| switch (cmsg->cmsg_type) { |
| |
| case IP_PKTINFO: { |
| struct in_pktinfo *i = (struct in_pktinfo*) CMSG_DATA(cmsg); |
| |
| if (s->ifindex <= 0) |
| s->ifindex = i->ipi_ifindex; |
| break; |
| } |
| |
| case IP_TTL: |
| s->ttl = *(int *) CMSG_DATA(cmsg); |
| break; |
| } |
| } |
| } |
| |
| /* The Linux kernel sets the interface index to the loopback |
| * device if the connection came from the local host since it |
| * avoids the routing table in such a case. Let's unset the |
| * interface index in such a case. */ |
| if (s->ifindex == LOOPBACK_IFINDEX) |
| s->ifindex = 0; |
| |
| /* If we don't know the interface index still, we look for the |
| * first local interface with a matching address. Yuck! */ |
| if (s->ifindex <= 0) |
| s->ifindex = manager_find_ifindex(s->manager, s->local.sa.sa_family, sockaddr_in_addr(&s->local.sa)); |
| |
| if (s->protocol == DNS_PROTOCOL_LLMNR && s->ifindex > 0) { |
| /* Make sure all packets for this connection are sent on the same interface */ |
| r = socket_set_unicast_if(s->fd, s->local.sa.sa_family, s->ifindex); |
| if (r < 0) |
| log_debug_errno(errno, "Failed to invoke IP_UNICAST_IF/IPV6_UNICAST_IF: %m"); |
| } |
| |
| s->identified = true; |
| |
| return 0; |
| } |
| |
| ssize_t dns_stream_writev(DnsStream *s, const struct iovec *iov, size_t iovcnt, int flags) { |
| ssize_t m; |
| |
| assert(s); |
| assert(iov); |
| |
| #if ENABLE_DNS_OVER_TLS |
| if (s->encrypted && !(flags & DNS_STREAM_WRITE_TLS_DATA)) { |
| ssize_t ss; |
| size_t i; |
| |
| m = 0; |
| for (i = 0; i < iovcnt; i++) { |
| ss = dnstls_stream_write(s, iov[i].iov_base, iov[i].iov_len); |
| if (ss < 0) |
| return ss; |
| |
| m += ss; |
| if (ss != (ssize_t) iov[i].iov_len) |
| continue; |
| } |
| } else |
| #endif |
| if (s->tfo_salen > 0) { |
| struct msghdr hdr = { |
| .msg_iov = (struct iovec*) iov, |
| .msg_iovlen = iovcnt, |
| .msg_name = &s->tfo_address.sa, |
| .msg_namelen = s->tfo_salen |
| }; |
| |
| m = sendmsg(s->fd, &hdr, MSG_FASTOPEN); |
| if (m < 0) { |
| if (errno == EOPNOTSUPP) { |
| s->tfo_salen = 0; |
| if (connect(s->fd, &s->tfo_address.sa, s->tfo_salen) < 0) |
| return -errno; |
| |
| return -EAGAIN; |
| } |
| if (errno == EINPROGRESS) |
| return -EAGAIN; |
| |
| return -errno; |
| } else |
| s->tfo_salen = 0; /* connection is made */ |
| } else { |
| m = writev(s->fd, iov, iovcnt); |
| if (m < 0) |
| return -errno; |
| } |
| |
| return m; |
| } |
| |
| static ssize_t dns_stream_read(DnsStream *s, void *buf, size_t count) { |
| ssize_t ss; |
| |
| #if ENABLE_DNS_OVER_TLS |
| if (s->encrypted) |
| ss = dnstls_stream_read(s, buf, count); |
| else |
| #endif |
| { |
| ss = read(s->fd, buf, count); |
| if (ss < 0) |
| return -errno; |
| } |
| |
| return ss; |
| } |
| |
| static int on_stream_timeout(sd_event_source *es, usec_t usec, void *userdata) { |
| DnsStream *s = userdata; |
| |
| assert(s); |
| |
| return dns_stream_complete(s, ETIMEDOUT); |
| } |
| |
| static int on_stream_io(sd_event_source *es, int fd, uint32_t revents, void *userdata) { |
| _cleanup_(dns_stream_unrefp) DnsStream *s = dns_stream_ref(userdata); /* Protect stream while we process it */ |
| bool progressed = false; |
| int r; |
| |
| assert(s); |
| |
| #if ENABLE_DNS_OVER_TLS |
| if (s->encrypted) { |
| r = dnstls_stream_on_io(s, revents); |
| if (r == DNSTLS_STREAM_CLOSED) |
| return 0; |
| if (r == -EAGAIN) |
| return dns_stream_update_io(s); |
| if (r < 0) |
| return dns_stream_complete(s, -r); |
| |
| r = dns_stream_update_io(s); |
| if (r < 0) |
| return r; |
| } |
| #endif |
| |
| /* only identify after connecting */ |
| if (s->tfo_salen == 0) { |
| r = dns_stream_identify(s); |
| if (r < 0) |
| return dns_stream_complete(s, -r); |
| } |
| |
| if ((revents & EPOLLOUT) && |
| s->write_packet && |
| s->n_written < sizeof(s->write_size) + s->write_packet->size) { |
| |
| struct iovec iov[] = { |
| IOVEC_MAKE(&s->write_size, sizeof(s->write_size)), |
| IOVEC_MAKE(DNS_PACKET_DATA(s->write_packet), s->write_packet->size), |
| }; |
| |
| IOVEC_INCREMENT(iov, ELEMENTSOF(iov), s->n_written); |
| |
| ssize_t ss = dns_stream_writev(s, iov, ELEMENTSOF(iov), 0); |
| if (ss < 0) { |
| if (!IN_SET(-ss, EINTR, EAGAIN)) |
| return dns_stream_complete(s, -ss); |
| } else { |
| progressed = true; |
| s->n_written += ss; |
| } |
| |
| /* Are we done? If so, disable the event source for EPOLLOUT */ |
| if (s->n_written >= sizeof(s->write_size) + s->write_packet->size) { |
| r = dns_stream_update_io(s); |
| if (r < 0) |
| return dns_stream_complete(s, -r); |
| } |
| } |
| |
| if ((revents & (EPOLLIN|EPOLLHUP|EPOLLRDHUP)) && |
| (!s->read_packet || |
| s->n_read < sizeof(s->read_size) + s->read_packet->size)) { |
| |
| if (s->n_read < sizeof(s->read_size)) { |
| ssize_t ss; |
| |
| ss = dns_stream_read(s, (uint8_t*) &s->read_size + s->n_read, sizeof(s->read_size) - s->n_read); |
| if (ss < 0) { |
| if (!IN_SET(-ss, EINTR, EAGAIN)) |
| return dns_stream_complete(s, -ss); |
| } else if (ss == 0) |
| return dns_stream_complete(s, ECONNRESET); |
| else { |
| progressed = true; |
| s->n_read += ss; |
| } |
| } |
| |
| if (s->n_read >= sizeof(s->read_size)) { |
| |
| if (be16toh(s->read_size) < DNS_PACKET_HEADER_SIZE) |
| return dns_stream_complete(s, EBADMSG); |
| |
| if (s->n_read < sizeof(s->read_size) + be16toh(s->read_size)) { |
| ssize_t ss; |
| |
| if (!s->read_packet) { |
| r = dns_packet_new(&s->read_packet, s->protocol, be16toh(s->read_size), DNS_PACKET_SIZE_MAX); |
| if (r < 0) |
| return dns_stream_complete(s, -r); |
| |
| s->read_packet->size = be16toh(s->read_size); |
| s->read_packet->ipproto = IPPROTO_TCP; |
| s->read_packet->family = s->peer.sa.sa_family; |
| s->read_packet->ttl = s->ttl; |
| s->read_packet->ifindex = s->ifindex; |
| s->read_packet->timestamp = now(clock_boottime_or_monotonic()); |
| |
| if (s->read_packet->family == AF_INET) { |
| s->read_packet->sender.in = s->peer.in.sin_addr; |
| s->read_packet->sender_port = be16toh(s->peer.in.sin_port); |
| s->read_packet->destination.in = s->local.in.sin_addr; |
| s->read_packet->destination_port = be16toh(s->local.in.sin_port); |
| } else { |
| assert(s->read_packet->family == AF_INET6); |
| s->read_packet->sender.in6 = s->peer.in6.sin6_addr; |
| s->read_packet->sender_port = be16toh(s->peer.in6.sin6_port); |
| s->read_packet->destination.in6 = s->local.in6.sin6_addr; |
| s->read_packet->destination_port = be16toh(s->local.in6.sin6_port); |
| |
| if (s->read_packet->ifindex == 0) |
| s->read_packet->ifindex = s->peer.in6.sin6_scope_id; |
| if (s->read_packet->ifindex == 0) |
| s->read_packet->ifindex = s->local.in6.sin6_scope_id; |
| } |
| } |
| |
| ss = dns_stream_read(s, |
| (uint8_t*) DNS_PACKET_DATA(s->read_packet) + s->n_read - sizeof(s->read_size), |
| sizeof(s->read_size) + be16toh(s->read_size) - s->n_read); |
| if (ss < 0) { |
| if (!IN_SET(-ss, EINTR, EAGAIN)) |
| return dns_stream_complete(s, -ss); |
| } else if (ss == 0) |
| return dns_stream_complete(s, ECONNRESET); |
| else |
| s->n_read += ss; |
| } |
| |
| /* Are we done? If so, disable the event source for EPOLLIN */ |
| if (s->n_read >= sizeof(s->read_size) + be16toh(s->read_size)) { |
| /* If there's a packet handler |
| * installed, call that. Note that |
| * this is optional... */ |
| if (s->on_packet) { |
| r = s->on_packet(s); |
| if (r < 0) |
| return r; |
| } |
| |
| r = dns_stream_update_io(s); |
| if (r < 0) |
| return dns_stream_complete(s, -r); |
| } |
| } |
| } |
| |
| /* Call "complete" callback if finished reading and writing one packet, and there's nothing else left |
| * to write. */ |
| if (s->type == DNS_STREAM_LLMNR_SEND && |
| (s->write_packet && s->n_written >= sizeof(s->write_size) + s->write_packet->size) && |
| ordered_set_isempty(s->write_queue) && |
| (s->read_packet && s->n_read >= sizeof(s->read_size) + s->read_packet->size)) |
| return dns_stream_complete(s, 0); |
| |
| /* If we did something, let's restart the timeout event source */ |
| if (progressed && s->timeout_event_source) { |
| r = sd_event_source_set_time_relative(s->timeout_event_source, DNS_STREAM_TIMEOUT_USEC); |
| if (r < 0) |
| log_warning_errno(errno, "Couldn't restart TCP connection timeout, ignoring: %m"); |
| } |
| |
| return 0; |
| } |
| |
| static DnsStream *dns_stream_free(DnsStream *s) { |
| DnsPacket *p; |
| |
| assert(s); |
| |
| dns_stream_stop(s); |
| |
| if (s->manager) { |
| LIST_REMOVE(streams, s->manager->dns_streams, s); |
| s->manager->n_dns_streams[s->type]--; |
| } |
| |
| #if ENABLE_DNS_OVER_TLS |
| if (s->encrypted) |
| dnstls_stream_free(s); |
| #endif |
| |
| ORDERED_SET_FOREACH(p, s->write_queue) |
| dns_packet_unref(ordered_set_remove(s->write_queue, p)); |
| |
| dns_packet_unref(s->write_packet); |
| dns_packet_unref(s->read_packet); |
| dns_server_unref(s->server); |
| |
| ordered_set_free(s->write_queue); |
| |
| return mfree(s); |
| } |
| |
| DEFINE_TRIVIAL_REF_UNREF_FUNC(DnsStream, dns_stream, dns_stream_free); |
| |
| int dns_stream_new( |
| Manager *m, |
| DnsStream **ret, |
| DnsStreamType type, |
| DnsProtocol protocol, |
| int fd, |
| const union sockaddr_union *tfo_address) { |
| |
| _cleanup_(dns_stream_unrefp) DnsStream *s = NULL; |
| int r; |
| |
| assert(m); |
| assert(ret); |
| assert(type >= 0); |
| assert(type < _DNS_STREAM_TYPE_MAX); |
| assert(protocol >= 0); |
| assert(protocol < _DNS_PROTOCOL_MAX); |
| assert(fd >= 0); |
| |
| if (m->n_dns_streams[type] > DNS_STREAMS_MAX) |
| return -EBUSY; |
| |
| s = new(DnsStream, 1); |
| if (!s) |
| return -ENOMEM; |
| |
| *s = (DnsStream) { |
| .n_ref = 1, |
| .fd = -1, |
| .protocol = protocol, |
| .type = type, |
| }; |
| |
| r = ordered_set_ensure_allocated(&s->write_queue, &dns_packet_hash_ops); |
| if (r < 0) |
| return r; |
| |
| r = sd_event_add_io(m->event, &s->io_event_source, fd, EPOLLIN, on_stream_io, s); |
| if (r < 0) |
| return r; |
| |
| (void) sd_event_source_set_description(s->io_event_source, "dns-stream-io"); |
| |
| r = sd_event_add_time_relative( |
| m->event, |
| &s->timeout_event_source, |
| clock_boottime_or_monotonic(), |
| DNS_STREAM_TIMEOUT_USEC, 0, |
| on_stream_timeout, s); |
| if (r < 0) |
| return r; |
| |
| (void) sd_event_source_set_description(s->timeout_event_source, "dns-stream-timeout"); |
| |
| LIST_PREPEND(streams, m->dns_streams, s); |
| m->n_dns_streams[type]++; |
| s->manager = m; |
| |
| s->fd = fd; |
| |
| if (tfo_address) { |
| s->tfo_address = *tfo_address; |
| s->tfo_salen = tfo_address->sa.sa_family == AF_INET6 ? sizeof(tfo_address->in6) : sizeof(tfo_address->in); |
| } |
| |
| *ret = TAKE_PTR(s); |
| |
| return 0; |
| } |
| |
| int dns_stream_write_packet(DnsStream *s, DnsPacket *p) { |
| int r; |
| |
| assert(s); |
| assert(p); |
| |
| r = ordered_set_put(s->write_queue, p); |
| if (r < 0) |
| return r; |
| |
| dns_packet_ref(p); |
| |
| return dns_stream_update_io(s); |
| } |
| |
| DnsPacket *dns_stream_take_read_packet(DnsStream *s) { |
| assert(s); |
| |
| if (!s->read_packet) |
| return NULL; |
| |
| if (s->n_read < sizeof(s->read_size)) |
| return NULL; |
| |
| if (s->n_read < sizeof(s->read_size) + be16toh(s->read_size)) |
| return NULL; |
| |
| s->n_read = 0; |
| return TAKE_PTR(s->read_packet); |
| } |
| |
| void dns_stream_detach(DnsStream *s) { |
| assert(s); |
| |
| if (!s->server) |
| return; |
| |
| if (s->server->stream != s) |
| return; |
| |
| dns_server_unref_stream(s->server); |
| } |
