return NULL;
sd_event_source_unref(t->timeout_event_source);
- dns_packet_unref(t->packet);
+
+ dns_packet_unref(t->sent);
+ dns_packet_unref(t->received);
+
+ sd_event_source_unref(t->tcp_event_source);
+ safe_close(t->tcp_fd);
if (t->query) {
LIST_REMOVE(transactions_by_query, t->query->transactions, t);
if (!t)
return -ENOMEM;
+ t->tcp_fd = -1;
+
do
random_bytes(&t->id, sizeof(t->id));
while (t->id == 0 ||
return 0;
}
+static void dns_query_transaction_stop(DnsQueryTransaction *t) {
+ assert(t);
+
+ t->timeout_event_source = sd_event_source_unref(t->timeout_event_source);
+ t->tcp_event_source = sd_event_source_unref(t->tcp_event_source);
+ t->tcp_fd = safe_close(t->tcp_fd);
+}
+
static void dns_query_transaction_set_state(DnsQueryTransaction *t, DnsQueryState state) {
assert(t);
t->state = state;
- if (state != DNS_QUERY_SENT)
- t->timeout_event_source = sd_event_source_unref(t->timeout_event_source);
+ if (state != DNS_QUERY_SENT) {
+ dns_query_transaction_stop(t);
+ dns_query_finish(t->query);
+ }
+}
+
+static int on_tcp_ready(sd_event_source *s, int fd, uint32_t revents, void *userdata) {
+ DnsQueryTransaction *t = userdata;
+ int r;
+
+ assert(t);
+
+ if (revents & EPOLLOUT) {
+ struct iovec iov[2];
+ be16_t sz;
+ ssize_t ss;
+
+ sz = htobe16(t->sent->size);
+
+ iov[0].iov_base = &sz;
+ iov[0].iov_len = sizeof(sz);
+ iov[1].iov_base = DNS_PACKET_DATA(t->sent);
+ iov[1].iov_len = t->sent->size;
+
+ IOVEC_INCREMENT(iov, 2, t->tcp_written);
+
+ ss = writev(fd, iov, 2);
+ if (ss < 0) {
+ if (errno != EINTR && errno != EAGAIN) {
+ dns_query_transaction_set_state(t, DNS_QUERY_RESOURCES);
+ return -errno;
+ }
+ } else
+ t->tcp_written += ss;
+
+ /* Are we done? If so, disable the event source for EPOLLOUT */
+ if (t->tcp_written >= sizeof(sz) + t->sent->size) {
+ r = sd_event_source_set_io_events(s, EPOLLIN);
+ if (r < 0) {
+ dns_query_transaction_set_state(t, DNS_QUERY_RESOURCES);
+ return r;
+ }
+ }
+ }
+
+ if (revents & (EPOLLIN|EPOLLHUP|EPOLLRDHUP)) {
+
+ if (t->tcp_read < sizeof(t->tcp_read_size)) {
+ ssize_t ss;
+
+ ss = read(fd, (uint8_t*) &t->tcp_read_size + t->tcp_read, sizeof(t->tcp_read_size) - t->tcp_read);
+ if (ss < 0) {
+ if (errno != EINTR && errno != EAGAIN) {
+ dns_query_transaction_set_state(t, DNS_QUERY_RESOURCES);
+ return -errno;
+ }
+ } else if (ss == 0) {
+ dns_query_transaction_set_state(t, DNS_QUERY_RESOURCES);
+ return -EIO;
+ } else
+ t->tcp_read += ss;
+ }
+
+ if (t->tcp_read >= sizeof(t->tcp_read_size)) {
+
+ if (be16toh(t->tcp_read_size) < DNS_PACKET_HEADER_SIZE) {
+ dns_query_transaction_set_state(t, DNS_QUERY_INVALID_REPLY);
+ return -EBADMSG;
+ }
+
+ if (t->tcp_read < sizeof(t->tcp_read_size) + be16toh(t->tcp_read_size)) {
+ ssize_t ss;
+
+ if (!t->received) {
+ r = dns_packet_new(&t->received, be16toh(t->tcp_read_size));
+ if (r < 0) {
+ dns_query_transaction_set_state(t, DNS_QUERY_RESOURCES);
+ return r;
+ }
+ }
+
+ ss = read(fd,
+ (uint8_t*) DNS_PACKET_DATA(t->received) + t->tcp_read - sizeof(t->tcp_read_size),
+ sizeof(t->tcp_read_size) + be16toh(t->tcp_read_size) - t->tcp_read);
+ if (ss < 0) {
+ if (errno != EINTR && errno != EAGAIN) {
+ dns_query_transaction_set_state(t, DNS_QUERY_RESOURCES);
+ return -errno;
+ }
+ } else if (ss == 0) {
+ dns_query_transaction_set_state(t, DNS_QUERY_RESOURCES);
+ return -EIO;
+ } else
+ t->tcp_read += ss;
+ }
+
+ if (t->tcp_read >= sizeof(t->tcp_read_size) + be16toh(t->tcp_read_size)) {
+ t->received->size = be16toh(t->tcp_read_size);
+ dns_query_transaction_reply(t, t->received);
+ return 0;
+ }
+ }
+ }
+
+ return 0;
+}
+
+static int dns_query_transaction_start_tcp(DnsQueryTransaction *t) {
+ int r;
+
+ assert(t);
+
+ if (t->tcp_fd >= 0)
+ return 0;
+
+ t->tcp_written = 0;
+ t->tcp_read = 0;
+ t->received = dns_packet_unref(t->received);
+
+ t->tcp_fd = dns_scope_tcp_socket(t->scope);
+ if (t->tcp_fd < 0)
+ return t->tcp_fd;
+
+ r = sd_event_add_io(t->query->manager->event, &t->tcp_event_source, t->tcp_fd, EPOLLIN|EPOLLOUT, on_tcp_ready, t);
+ if (r < 0) {
+ t->tcp_fd = safe_close(t->tcp_fd);
+ return r;
+ }
- dns_query_finish(t->query);
+ return 0;
}
-int dns_query_transaction_reply(DnsQueryTransaction *t, DnsPacket *p) {
+void dns_query_transaction_reply(DnsQueryTransaction *t, DnsPacket *p) {
+ int r;
+
assert(t);
assert(p);
- t->packet = dns_packet_ref(p);
+ if (t->state != DNS_QUERY_SENT)
+ return;
+
+ if (t->received != p) {
+ dns_packet_unref(t->received);
+ t->received = dns_packet_ref(p);
+ }
+
+ if (t->tcp_fd >= 0) {
+ if (DNS_PACKET_TC(p)) {
+ /* Truncated via TCP? Somebody must be fucking with us */
+ dns_query_transaction_set_state(t, DNS_QUERY_INVALID_REPLY);
+ return;
+ }
+
+ if (DNS_PACKET_ID(p) != t->id) {
+ /* Not the reply to our query? Somebody must be fucking with us */
+ dns_query_transaction_set_state(t, DNS_QUERY_INVALID_REPLY);
+ return;
+ }
+ }
+
+ if (DNS_PACKET_TC(p)) {
+ /* Response was truncated, let's try again with good old TCP */
+ r = dns_query_transaction_start_tcp(t);
+ if (r < 0) {
+ dns_query_transaction_set_state(t, DNS_QUERY_RESOURCES);
+ return;
+ }
+ }
if (DNS_PACKET_RCODE(p) == DNS_RCODE_SUCCESS)
dns_query_transaction_set_state(t, DNS_QUERY_SUCCESS);
else
dns_query_transaction_set_state(t, DNS_QUERY_FAILURE);
-
- return 0;
}
static int on_transaction_timeout(sd_event_source *s, usec_t usec, void *userdata) {
r = dns_query_transaction_start(t);
if (r < 0)
- dns_query_transaction_set_state(t, DNS_QUERY_FAILURE);
+ dns_query_transaction_set_state(t, DNS_QUERY_RESOURCES);
return 0;
}
-int dns_query_transaction_start(DnsQueryTransaction *t) {
+static int dns_query_make_packet(DnsQueryTransaction *t) {
_cleanup_(dns_packet_unrefp) DnsPacket *p = NULL;
unsigned n;
int r;
assert(t);
- t->timeout_event_source = sd_event_source_unref(t->timeout_event_source);
-
- if (t->n_attempts >= ATTEMPTS_MAX) {
- dns_query_transaction_set_state(t, DNS_QUERY_ATTEMPTS_MAX);
+ if (t->sent)
return 0;
- }
-
- t->n_attempts++;
r = dns_packet_new_query(&p, 0);
if (r < 0)
DNS_PACKET_HEADER(p)->qdcount = htobe16(t->query->n_keys);
DNS_PACKET_HEADER(p)->id = t->id;
- r = dns_scope_send(t->scope, p);
+ t->sent = p;
+ p = NULL;
+
+ return 0;
+}
+
+int dns_query_transaction_start(DnsQueryTransaction *t) {
+ int r;
+
+ assert(t);
+
+ dns_query_transaction_stop(t);
+
+ if (t->n_attempts >= ATTEMPTS_MAX) {
+ dns_query_transaction_set_state(t, DNS_QUERY_ATTEMPTS_MAX);
+ return 0;
+ }
+ t->n_attempts++;
+
+ r = dns_query_make_packet(t);
+ if (r < 0)
+ return r;
+
+ /* Try via UDP, and if that fails due to large size try via TCP */
+ r = dns_scope_send(t->scope, t->sent);
+ if (r == -EMSGSIZE)
+ r = dns_query_transaction_start_tcp(t);
+
+ if (r == -ESRCH) {
+ dns_query_transaction_set_state(t, DNS_QUERY_NO_SERVERS);
+ return 0;
+ }
if (r < 0) {
/* Couldn't send? Try immediately again, with a new server */
dns_scope_next_dns_server(t->scope);
return dns_query_transaction_start(t);
}
- if (r > 0) {
- int q;
-
- q = sd_event_add_time(t->query->manager->event, &t->timeout_event_source, CLOCK_MONOTONIC, now(CLOCK_MONOTONIC) + TRANSACTION_TIMEOUT_USEC, 0, on_transaction_timeout, t);
- if (q < 0)
- return q;
-
- dns_query_transaction_set_state(t, DNS_QUERY_SENT);
- } else
- dns_query_transaction_set_state(t, DNS_QUERY_SKIPPED);
+ r = sd_event_add_time(t->query->manager->event, &t->timeout_event_source, CLOCK_MONOTONIC, now(CLOCK_MONOTONIC) + TRANSACTION_TIMEOUT_USEC, 0, on_transaction_timeout, t);
+ if (r < 0)
+ return r;
- return r;
+ dns_query_transaction_set_state(t, DNS_QUERY_SENT);
+ return 1;
}
DnsQuery *dns_query_free(DnsQuery *q) {
return NULL;
sd_bus_message_unref(q->request);
- dns_packet_unref(q->packet);
+ dns_packet_unref(q->received);
sd_event_source_unref(q->timeout_event_source);
while (q->transactions)
void dns_query_finish(DnsQuery *q) {
DnsQueryTransaction *t;
- DnsQueryState state = DNS_QUERY_SKIPPED;
- uint16_t rcode = 0;
+ DnsQueryState state = DNS_QUERY_NO_SERVERS;
+ DnsPacket *received = NULL;
assert(q);
if (t->state == DNS_QUERY_SENT || t->state == DNS_QUERY_NULL)
return;
- /* One of the transactions is sucecssful, let's use it */
+ /* One of the transactions is successful, let's use it */
if (t->state == DNS_QUERY_SUCCESS) {
- q->packet = dns_packet_ref(t->packet);
+ q->received = dns_packet_ref(t->received);
dns_query_set_state(q, DNS_QUERY_SUCCESS);
return;
}
+ /* One of the transactions has failed, let's see
+ * whether we find anything better, but if not, return
+ * its response packet */
if (t->state == DNS_QUERY_FAILURE) {
+ received = t->received;
state = DNS_QUERY_FAILURE;
+ continue;
+ }
- if (rcode == 0 && t->packet)
- rcode = DNS_PACKET_RCODE(t->packet);
-
- } else if (state == DNS_QUERY_SKIPPED && t->state != DNS_QUERY_SKIPPED)
+ if (state == DNS_QUERY_NO_SERVERS && t->state != DNS_QUERY_NO_SERVERS)
state = t->state;
}
if (state == DNS_QUERY_FAILURE)
- q->rcode = rcode;
+ q->received = dns_packet_ref(received);
dns_query_set_state(q, state);
}
~ianmdlvl / elogind.git / blobdiff