mirror of
https://github.com/samba-team/samba.git
synced 2024-12-22 13:34:15 +03:00
libdns: dns/tcp client
Same signature as the UDP client in the same file. This opens and closes the socket per request. In the future, we might want to create a persistent TCP connection for our internal DNS server's forwarder. That will require proper handling of in-flight requests. Something for another day. Signed-off-by: Volker Lendecke <vl@samba.org> Reviewed-by: Jeremy Allison <jra@samba.org>
This commit is contained in:
Volker Lendecke
Jeremy Allison
parent
507c9b6906
commit
623883083b
219
libcli/dns/dns.c
219
libcli/dns/dns.c
@ -176,3 +176,222 @@ int dns_udp_request_recv(struct tevent_req *req,
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
struct dns_tcp_request_state {
|
||||
struct tevent_context *ev;
|
||||
struct tstream_context *stream;
|
||||
const uint8_t *query;
|
||||
size_t query_len;
|
||||
|
||||
uint8_t dns_msglen_hdr[2];
|
||||
struct iovec iov[2];
|
||||
|
||||
size_t nread;
|
||||
uint8_t *reply;
|
||||
};
|
||||
|
||||
static void dns_tcp_request_connected(struct tevent_req *subreq);
|
||||
static void dns_tcp_request_sent(struct tevent_req *subreq);
|
||||
static int dns_tcp_request_next_vector(struct tstream_context *stream,
|
||||
void *private_data,
|
||||
TALLOC_CTX *mem_ctx,
|
||||
struct iovec **_vector,
|
||||
size_t *_count);
|
||||
static void dns_tcp_request_received(struct tevent_req *subreq);
|
||||
|
||||
struct tevent_req *dns_tcp_request_send(TALLOC_CTX *mem_ctx,
|
||||
struct tevent_context *ev,
|
||||
const char *server_addr_string,
|
||||
const uint8_t *query,
|
||||
size_t query_len)
|
||||
{
|
||||
struct tevent_req *req, *subreq;
|
||||
struct dns_tcp_request_state *state;
|
||||
struct tsocket_address *local, *remote;
|
||||
int ret;
|
||||
|
||||
req = tevent_req_create(mem_ctx, &state,
|
||||
struct dns_tcp_request_state);
|
||||
if (req == NULL) {
|
||||
return NULL;
|
||||
}
|
||||
state->ev = ev;
|
||||
state->query = query;
|
||||
state->query_len = query_len;
|
||||
|
||||
if (query_len > UINT16_MAX) {
|
||||
tevent_req_error(req, EMSGSIZE);
|
||||
return tevent_req_post(req, ev);
|
||||
}
|
||||
|
||||
ret = tsocket_address_inet_from_strings(state, "ip", NULL, 0, &local);
|
||||
if (ret != 0) {
|
||||
tevent_req_error(req, errno);
|
||||
return tevent_req_post(req, ev);
|
||||
}
|
||||
|
||||
ret = tsocket_address_inet_from_strings(
|
||||
state, "ip", server_addr_string, DNS_SERVICE_PORT, &remote);
|
||||
if (ret != 0) {
|
||||
tevent_req_error(req, errno);
|
||||
return tevent_req_post(req, ev);
|
||||
}
|
||||
|
||||
subreq = tstream_inet_tcp_connect_send(state, state->ev,
|
||||
local, remote);
|
||||
if (tevent_req_nomem(subreq, req)) {
|
||||
return tevent_req_post(req, ev);
|
||||
}
|
||||
tevent_req_set_callback(subreq, dns_tcp_request_connected, req);
|
||||
|
||||
return req;
|
||||
}
|
||||
|
||||
static void dns_tcp_request_connected(struct tevent_req *subreq)
|
||||
{
|
||||
struct tevent_req *req = tevent_req_callback_data(
|
||||
subreq, struct tevent_req);
|
||||
struct dns_tcp_request_state *state = tevent_req_data(
|
||||
req, struct dns_tcp_request_state);
|
||||
int ret, err;
|
||||
|
||||
ret = tstream_inet_tcp_connect_recv(subreq, &err, state,
|
||||
&state->stream, NULL);
|
||||
TALLOC_FREE(subreq);
|
||||
if (ret == -1) {
|
||||
tevent_req_error(req, err);
|
||||
return;
|
||||
}
|
||||
|
||||
RSSVAL(state->dns_msglen_hdr, 0, state->query_len);
|
||||
state->iov[0] = (struct iovec) {
|
||||
.iov_base = state->dns_msglen_hdr,
|
||||
.iov_len = sizeof(state->dns_msglen_hdr)
|
||||
};
|
||||
state->iov[1] = (struct iovec) {
|
||||
.iov_base = discard_const_p(void, state->query),
|
||||
.iov_len = state->query_len
|
||||
};
|
||||
|
||||
subreq = tstream_writev_send(state, state->ev, state->stream,
|
||||
state->iov, ARRAY_SIZE(state->iov));
|
||||
if (tevent_req_nomem(subreq, req)) {
|
||||
return;
|
||||
}
|
||||
tevent_req_set_callback(subreq, dns_tcp_request_sent, req);
|
||||
}
|
||||
|
||||
static void dns_tcp_request_sent(struct tevent_req *subreq)
|
||||
{
|
||||
struct tevent_req *req = tevent_req_callback_data(
|
||||
subreq, struct tevent_req);
|
||||
struct dns_tcp_request_state *state = tevent_req_data(
|
||||
req, struct dns_tcp_request_state);
|
||||
int ret, err;
|
||||
|
||||
ret = tstream_writev_recv(subreq, &err);
|
||||
TALLOC_FREE(subreq);
|
||||
if (ret == -1) {
|
||||
tevent_req_error(req, err);
|
||||
return;
|
||||
}
|
||||
|
||||
subreq = tstream_readv_pdu_send(state, state->ev, state->stream,
|
||||
dns_tcp_request_next_vector, state);
|
||||
if (tevent_req_nomem(subreq, req)) {
|
||||
return;
|
||||
}
|
||||
tevent_req_set_callback(subreq, dns_tcp_request_received, req);
|
||||
}
|
||||
|
||||
static int dns_tcp_request_next_vector(struct tstream_context *stream,
|
||||
void *private_data,
|
||||
TALLOC_CTX *mem_ctx,
|
||||
struct iovec **_vector,
|
||||
size_t *_count)
|
||||
{
|
||||
struct dns_tcp_request_state *state = talloc_get_type_abort(
|
||||
private_data, struct dns_tcp_request_state);
|
||||
struct iovec *vector;
|
||||
uint16_t msglen;
|
||||
|
||||
if (state->nread == 0) {
|
||||
vector = talloc_array(mem_ctx, struct iovec, 1);
|
||||
if (vector == NULL) {
|
||||
return -1;
|
||||
}
|
||||
vector[0] = (struct iovec) {
|
||||
.iov_base = state->dns_msglen_hdr,
|
||||
.iov_len = sizeof(state->dns_msglen_hdr)
|
||||
};
|
||||
state->nread = sizeof(state->dns_msglen_hdr);
|
||||
|
||||
*_vector = vector;
|
||||
*_count = 1;
|
||||
return 0;
|
||||
}
|
||||
|
||||
if (state->nread == sizeof(state->dns_msglen_hdr)) {
|
||||
msglen = RSVAL(state->dns_msglen_hdr, 0);
|
||||
|
||||
state->reply = talloc_array(state, uint8_t, msglen);
|
||||
if (state->reply == NULL) {
|
||||
return -1;
|
||||
}
|
||||
|
||||
vector = talloc_array(mem_ctx, struct iovec, 1);
|
||||
if (vector == NULL) {
|
||||
return -1;
|
||||
}
|
||||
vector[0] = (struct iovec) {
|
||||
.iov_base = state->reply,
|
||||
.iov_len = msglen
|
||||
};
|
||||
state->nread += msglen;
|
||||
|
||||
*_vector = vector;
|
||||
*_count = 1;
|
||||
return 0;
|
||||
}
|
||||
|
||||
*_vector = NULL;
|
||||
*_count = 0;
|
||||
return 0;
|
||||
}
|
||||
|
||||
static void dns_tcp_request_received(struct tevent_req *subreq)
|
||||
{
|
||||
struct tevent_req *req = tevent_req_callback_data(
|
||||
subreq, struct tevent_req);
|
||||
int ret, err;
|
||||
|
||||
ret = tstream_readv_pdu_recv(subreq, &err);
|
||||
TALLOC_FREE(subreq);
|
||||
if (ret == -1) {
|
||||
tevent_req_error(req, err);
|
||||
return;
|
||||
}
|
||||
|
||||
tevent_req_done(req);
|
||||
}
|
||||
|
||||
int dns_tcp_request_recv(struct tevent_req *req,
|
||||
TALLOC_CTX *mem_ctx,
|
||||
uint8_t **reply,
|
||||
size_t *reply_len)
|
||||
{
|
||||
struct dns_tcp_request_state *state = tevent_req_data(
|
||||
req, struct dns_tcp_request_state);
|
||||
int err;
|
||||
|
||||
if (tevent_req_is_unix_error(req, &err)) {
|
||||
tevent_req_received(req);
|
||||
return err;
|
||||
}
|
||||
|
||||
*reply_len = talloc_array_length(state->reply);
|
||||
*reply = talloc_move(mem_ctx, &state->reply);
|
||||
tevent_req_received(req);
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
@ -50,4 +50,14 @@ int dns_udp_request_recv(struct tevent_req *req,
|
||||
uint8_t **reply,
|
||||
size_t *reply_len);
|
||||
|
||||
struct tevent_req *dns_tcp_request_send(TALLOC_CTX *mem_ctx,
|
||||
struct tevent_context *ev,
|
||||
const char *server_addr_string,
|
||||
const uint8_t *query,
|
||||
size_t query_len);
|
||||
int dns_tcp_request_recv(struct tevent_req *req,
|
||||
TALLOC_CTX *mem_ctx,
|
||||
uint8_t **reply,
|
||||
size_t *reply_len);
|
||||
|
||||
#endif /*__LIBDNS_H__*/
|
||||
|
||||
Loading…
Reference in New Issue
Block a user