/** Helper function: called whenever the client sends a resolve request to our
* controller. We need to eventually answer the request <b>req</b>.
* Returns 0 if the controller will be getting (or has gotten) an event in
* response; -1 if we couldn't launch the request.
*/
int
dnsserv_launch_request(const char *name, int reverse)
{
entry_connection_t *entry_conn;
edge_connection_t *conn;
char *q_name;
/* Make a new dummy AP connection, and attach the request to it. */
entry_conn = entry_connection_new(CONN_TYPE_AP, AF_INET);
conn = ENTRY_TO_EDGE_CONN(entry_conn);
conn->base_.state = AP_CONN_STATE_RESOLVE_WAIT;
if (reverse)
entry_conn->socks_request->command = SOCKS_COMMAND_RESOLVE_PTR;
else
entry_conn->socks_request->command = SOCKS_COMMAND_RESOLVE;
conn->is_dns_request = 1;
strlcpy(entry_conn->socks_request->address, name,
sizeof(entry_conn->socks_request->address));
entry_conn->socks_request->listener_type = CONN_TYPE_CONTROL_LISTENER;
entry_conn->original_dest_address = tor_strdup(name);
entry_conn->session_group = SESSION_GROUP_CONTROL_RESOLVE;
entry_conn->nym_epoch = get_signewnym_epoch();
entry_conn->isolation_flags = ISO_DEFAULT;
if (connection_add(TO_CONN(conn))<0) {
log_warn(LD_APP, "Couldn't register dummy connection for RESOLVE request");
connection_free(TO_CONN(conn));
return -1;
}
/* Now, unless a controller asked us to leave streams unattached,
* throw the connection over to get rewritten (which will
* answer it immediately if it's in the cache, or completely bogus, or
* automapped), and then attached to a circuit. */
log_info(LD_APP, "Passing request for %s to rewrite_and_attach.",
escaped_safe_str_client(name));
q_name = tor_strdup(name); /* q could be freed in rewrite_and_attach */
connection_ap_rewrite_and_attach_if_allowed(entry_conn, NULL, NULL);
/* Now, the connection is marked if it was bad. */
log_info(LD_APP, "Passed request for %s to rewrite_and_attach_if_allowed.",
escaped_safe_str_client(q_name));
tor_free(q_name);
return 0;
}
/** Helper function: called by evdns whenever the client sends a request to our
* DNSPort. We need to eventually answer the request <b>req</b>.
*/
static void
evdns_server_callback(struct evdns_server_request *req, void *data_)
{
const listener_connection_t *listener = data_;
entry_connection_t *entry_conn;
edge_connection_t *conn;
int i = 0;
struct evdns_server_question *q = NULL, *supported_q = NULL;
struct sockaddr_storage addr;
struct sockaddr *sa;
int addrlen;
tor_addr_t tor_addr;
uint16_t port;
int err = DNS_ERR_NONE;
char *q_name;
tor_assert(req);
log_info(LD_APP, "Got a new DNS request!");
req->flags |= 0x80; /* set RA */
/* First, check whether the requesting address matches our SOCKSPolicy. */
if ((addrlen = evdns_server_request_get_requesting_addr(req,
(struct sockaddr*)&addr, (socklen_t)sizeof(addr))) < 0) {
log_warn(LD_APP, "Couldn't get requesting address.");
evdns_server_request_respond(req, DNS_ERR_SERVERFAILED);
return;
}
(void) addrlen;
sa = (struct sockaddr*) &addr;
if (tor_addr_from_sockaddr(&tor_addr, sa, &port)<0) {
log_warn(LD_APP, "Requesting address wasn't recognized.");
evdns_server_request_respond(req, DNS_ERR_SERVERFAILED);
return;
}
if (!socks_policy_permits_address(&tor_addr)) {
log_warn(LD_APP, "Rejecting DNS request from disallowed IP.");
evdns_server_request_respond(req, DNS_ERR_REFUSED);
return;
}
/* Now, let's find the first actual question of a type we can answer in this
* DNS request. It makes us a little noncompliant to act like this; we
* should fix that eventually if it turns out to make a difference for
* anybody. */
if (req->nquestions == 0) {
log_info(LD_APP, "No questions in DNS request; sending back nil reply.");
evdns_server_request_respond(req, 0);
return;
}
if (req->nquestions > 1) {
log_info(LD_APP, "Got a DNS request with more than one question; I only "
"handle one question at a time for now. Skipping the extras.");
}
for (i = 0; i < req->nquestions; ++i) {
if (req->questions[i]->dns_question_class != EVDNS_CLASS_INET)
continue;
switch (req->questions[i]->type) {
case EVDNS_TYPE_A:
case EVDNS_TYPE_AAAA:
case EVDNS_TYPE_PTR:
/* We always pick the first one of these questions, if there is
one. */
if (! supported_q)
supported_q = req->questions[i];
break;
default:
break;
}
}
if (supported_q)
q = supported_q;
if (!q) {
log_info(LD_APP, "None of the questions we got were ones we're willing "
"to support. Sending NOTIMPL.");
evdns_server_request_respond(req, DNS_ERR_NOTIMPL);
return;
}
/* Make sure the name isn't too long: This should be impossible, I think. */
if (err == DNS_ERR_NONE && strlen(q->name) > MAX_SOCKS_ADDR_LEN-1)
err = DNS_ERR_FORMAT;
if (err != DNS_ERR_NONE || !supported_q) {
/* We got an error? There's no question we're willing to answer? Then
* send back an answer immediately; we're done. */
evdns_server_request_respond(req, err);
return;
}
/* Make a new dummy AP connection, and attach the request to it. */
entry_conn = entry_connection_new(CONN_TYPE_AP, AF_INET);
conn = ENTRY_TO_EDGE_CONN(entry_conn);
CONNECTION_AP_EXPECT_NONPENDING(entry_conn);
TO_CONN(conn)->state = AP_CONN_STATE_RESOLVE_WAIT;
conn->is_dns_request = 1;
tor_addr_copy(&TO_CONN(conn)->addr, &tor_addr);
TO_CONN(conn)->port = port;
TO_CONN(conn)->address = tor_addr_to_str_dup(&tor_addr);
if (q->type == EVDNS_TYPE_A || q->type == EVDNS_TYPE_AAAA ||
q->type == EVDNS_QTYPE_ALL) {
entry_conn->socks_request->command = SOCKS_COMMAND_RESOLVE;
} else {
tor_assert(q->type == EVDNS_TYPE_PTR);
entry_conn->socks_request->command = SOCKS_COMMAND_RESOLVE_PTR;
}
/* This serves our DNS port so enable DNS request by default. */
entry_conn->entry_cfg.dns_request = 1;
if (q->type == EVDNS_TYPE_A || q->type == EVDNS_QTYPE_ALL) {
entry_conn->entry_cfg.ipv4_traffic = 1;
entry_conn->entry_cfg.ipv6_traffic = 0;
entry_conn->entry_cfg.prefer_ipv6 = 0;
} else if (q->type == EVDNS_TYPE_AAAA) {
entry_conn->entry_cfg.ipv4_traffic = 0;
entry_conn->entry_cfg.ipv6_traffic = 1;
entry_conn->entry_cfg.prefer_ipv6 = 1;
}
strlcpy(entry_conn->socks_request->address, q->name,
sizeof(entry_conn->socks_request->address));
entry_conn->socks_request->listener_type = listener->base_.type;
entry_conn->dns_server_request = req;
entry_conn->entry_cfg.isolation_flags = listener->entry_cfg.isolation_flags;
entry_conn->entry_cfg.session_group = listener->entry_cfg.session_group;
entry_conn->nym_epoch = get_signewnym_epoch();
if (connection_add(ENTRY_TO_CONN(entry_conn)) < 0) {
log_warn(LD_APP, "Couldn't register dummy connection for DNS request");
evdns_server_request_respond(req, DNS_ERR_SERVERFAILED);
connection_free(ENTRY_TO_CONN(entry_conn));
return;
}
control_event_stream_status(entry_conn, STREAM_EVENT_NEW_RESOLVE, 0);
/* Now, unless a controller asked us to leave streams unattached,
* throw the connection over to get rewritten (which will
* answer it immediately if it's in the cache, or completely bogus, or
* automapped), and then attached to a circuit. */
log_info(LD_APP, "Passing request for %s to rewrite_and_attach.",
escaped_safe_str_client(q->name));
q_name = tor_strdup(q->name); /* q could be freed in rewrite_and_attach */
connection_ap_rewrite_and_attach_if_allowed(entry_conn, NULL, NULL);
/* Now, the connection is marked if it was bad. */
log_info(LD_APP, "Passed request for %s to rewrite_and_attach_if_allowed.",
escaped_safe_str_client(q_name));
tor_free(q_name);
}
/** Helper function: called whenever the client sends a resolve request to our
* controller. We need to eventually answer the request <b>req</b>.
* Returns 0 if the controller will be getting (or has gotten) an event in
* response; -1 if we couldn't launch the request.
*/
int
dnsserv_launch_request(const char *name, int reverse,
control_connection_t *control_conn)
{
entry_connection_t *entry_conn;
edge_connection_t *conn;
char *q_name;
/* Make a new dummy AP connection, and attach the request to it. */
entry_conn = entry_connection_new(CONN_TYPE_AP, AF_INET);
conn = ENTRY_TO_EDGE_CONN(entry_conn);
CONNECTION_AP_EXPECT_NONPENDING(entry_conn);
conn->base_.state = AP_CONN_STATE_RESOLVE_WAIT;
tor_addr_copy(&TO_CONN(conn)->addr, &control_conn->base_.addr);
#ifdef AF_UNIX
/*
* The control connection can be AF_UNIX and if so tor_addr_to_str_dup will
* unhelpfully say "<unknown address type>"; say "(Tor_internal)"
* instead.
*/
if (control_conn->base_.socket_family == AF_UNIX) {
TO_CONN(conn)->port = 0;
TO_CONN(conn)->address = tor_strdup("(Tor_internal)");
} else {
TO_CONN(conn)->port = control_conn->base_.port;
TO_CONN(conn)->address = tor_addr_to_str_dup(&control_conn->base_.addr);
}
#else
TO_CONN(conn)->port = control_conn->base_.port;
TO_CONN(conn)->address = tor_addr_to_str_dup(&control_conn->base_.addr);
#endif
if (reverse)
entry_conn->socks_request->command = SOCKS_COMMAND_RESOLVE_PTR;
else
entry_conn->socks_request->command = SOCKS_COMMAND_RESOLVE;
conn->is_dns_request = 1;
strlcpy(entry_conn->socks_request->address, name,
sizeof(entry_conn->socks_request->address));
entry_conn->socks_request->listener_type = CONN_TYPE_CONTROL_LISTENER;
entry_conn->original_dest_address = tor_strdup(name);
entry_conn->entry_cfg.session_group = SESSION_GROUP_CONTROL_RESOLVE;
entry_conn->nym_epoch = get_signewnym_epoch();
entry_conn->entry_cfg.isolation_flags = ISO_DEFAULT;
if (connection_add(TO_CONN(conn))<0) {
log_warn(LD_APP, "Couldn't register dummy connection for RESOLVE request");
connection_free(TO_CONN(conn));
return -1;
}
control_event_stream_status(entry_conn, STREAM_EVENT_NEW_RESOLVE, 0);
/* Now, unless a controller asked us to leave streams unattached,
* throw the connection over to get rewritten (which will
* answer it immediately if it's in the cache, or completely bogus, or
* automapped), and then attached to a circuit. */
log_info(LD_APP, "Passing request for %s to rewrite_and_attach.",
escaped_safe_str_client(name));
q_name = tor_strdup(name); /* q could be freed in rewrite_and_attach */
connection_ap_rewrite_and_attach_if_allowed(entry_conn, NULL, NULL);
/* Now, the connection is marked if it was bad. */
log_info(LD_APP, "Passed request for %s to rewrite_and_attach_if_allowed.",
escaped_safe_str_client(q_name));
tor_free(q_name);
return 0;
}