Add infrastructure to support async SMB requests

(This used to be commit f5356825698a02df2d400b51dd95d1f857c83e81)

1 files changed, 483 insertions, 0 deletions

diff --git a/source3/libsmb/async_smb.c b/source3/libsmb/async_smb.c
new file mode 100644
index 0000000000..21bcd5b9b1
--- /dev/null
+++ b/source3/libsmb/async_smb.c
@@ -0,0 +1,483 @@
+/*
+   Unix SMB/CIFS implementation.
+   Infrastructure for async SMB client requests
+   Copyright (C) Volker Lendecke 2008
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include "includes.h"
+
+/*
+ * Fetch an error out of a NBT packet
+ */
+
+NTSTATUS cli_pull_error(char *buf)
+{
+	uint32_t flags2 = SVAL(buf, smb_flg2);
+
+	if (flags2 & FLAGS2_32_BIT_ERROR_CODES) {
+		return NT_STATUS(IVAL(buf, smb_rcls));
+	}
+
+	return NT_STATUS_DOS(CVAL(buf, smb_rcls), SVAL(buf,smb_err));
+}
+
+/*
+ * Compatibility helper for the sync APIs: Fake NTSTATUS in cli->inbuf
+ */
+
+void cli_set_error(struct cli_state *cli, NTSTATUS status)
+{
+	uint32_t flags2 = SVAL(cli->inbuf, smb_flg2);
+
+	if (NT_STATUS_IS_DOS(status)) {
+		SSVAL(cli->inbuf, smb_flg2,
+		      flags2 & ~FLAGS2_32_BIT_ERROR_CODES);
+		SCVAL(cli->inbuf, smb_rcls, NT_STATUS_DOS_CLASS(status));
+		SSVAL(cli->inbuf, smb_err, NT_STATUS_DOS_CODE(status));
+		return;
+	}
+
+	SSVAL(cli->inbuf, smb_flg2, flags2 | FLAGS2_32_BIT_ERROR_CODES);
+	SIVAL(cli->inbuf, smb_rcls, NT_STATUS_V(status));
+	return;
+}
+
+/*
+ * Allocate a new mid
+ */
+
+static uint16_t cli_new_mid(struct cli_state *cli)
+{
+	uint16_t result;
+	struct cli_request *req;
+
+	while (true) {
+		result = cli->mid++;
+		if (result == 0) {
+			continue;
+		}
+
+		for (req = cli->outstanding_requests; req; req = req->next) {
+			if (result == req->mid) {
+				break;
+			}
+		}
+
+		if (req == NULL) {
+			return result;
+		}
+	}
+}
+
+static char *cli_request_print(TALLOC_CTX *mem_ctx, struct async_req *req)
+{
+	char *result = async_req_print(mem_ctx, req);
+	struct cli_request *cli_req = cli_request_get(req);
+
+	if (result == NULL) {
+		return NULL;
+	}
+
+	return talloc_asprintf_append_buffer(
+		result, "mid=%d\n", cli_req->mid);
+}
+
+static int cli_request_destructor(struct cli_request *req)
+{
+	if (req->enc_state != NULL) {
+		common_free_enc_buffer(req->enc_state, req->outbuf);
+	}
+	DLIST_REMOVE(req->cli->outstanding_requests, req);
+	return 0;
+}
+
+/*
+ * Create a fresh async smb request
+ */
+
+struct async_req *cli_request_new(TALLOC_CTX *mem_ctx,
+				  struct event_context *ev,
+				  struct cli_state *cli,
+				  uint8_t num_words, size_t num_bytes,
+				  struct cli_request **preq)
+{
+	struct async_req *result;
+	struct cli_request *cli_req;
+	size_t bufsize = smb_size + num_words * 2 + num_bytes;
+
+	result = async_req_new(mem_ctx, ev);
+	if (result == NULL) {
+		return NULL;
+	}
+
+	cli_req = (struct cli_request *)talloc_size(
+		result, sizeof(*cli_req) + bufsize);
+	if (cli_req == NULL) {
+		TALLOC_FREE(result);
+		return NULL;
+	}
+	talloc_set_name_const(cli_req, "struct cli_request");
+	result->private_data = cli_req;
+	result->print = cli_request_print;
+
+	cli_req->async = result;
+	cli_req->cli = cli;
+	cli_req->outbuf = ((char *)cli_req + sizeof(*cli_req));
+	cli_req->sent = 0;
+	cli_req->mid = cli_new_mid(cli);
+	cli_req->inbuf = NULL;
+	cli_req->enc_state = NULL;
+
+	SCVAL(cli_req->outbuf, smb_wct, num_words);
+	SSVAL(cli_req->outbuf, smb_vwv + num_words * 2, num_bytes);
+
+	DLIST_ADD_END(cli->outstanding_requests, cli_req,
+		      struct cli_request *);
+	talloc_set_destructor(cli_req, cli_request_destructor);
+
+	DEBUG(10, ("cli_request_new: mid=%d\n", cli_req->mid));
+
+	*preq = cli_req;
+	return result;
+}
+
+/*
+ * Convenience function to get the SMB part out of an async_req
+ */
+
+struct cli_request *cli_request_get(struct async_req *req)
+{
+	if (req == NULL) {
+		return NULL;
+	}
+	return talloc_get_type_abort(req->private_data, struct cli_request);
+}
+
+/*
+ * A PDU has arrived on cli->evt_inbuf
+ */
+
+static void handle_incoming_pdu(struct cli_state *cli)
+{
+	struct cli_request *req;
+	uint16_t mid;
+	size_t raw_pdu_len, buf_len, pdu_len;
+	size_t rest_len;
+	NTSTATUS status;
+
+	/*
+	 * The encrypted PDU len might differ from the unencrypted one
+	 */
+	raw_pdu_len = smb_len(cli->evt_inbuf) + 4;
+
+	/*
+	 * TODO: Handle oplock break requests
+	 */
+
+	if (cli_encryption_on(cli) && CVAL(cli->evt_inbuf, 0) == 0) {
+		uint16_t enc_ctx_num;
+
+		status = get_enc_ctx_num((uint8_t *)cli->evt_inbuf,
+					 &enc_ctx_num);
+		if (!NT_STATUS_IS_OK(status)) {
+			DEBUG(10, ("get_enc_ctx_num returned %s\n",
+				   nt_errstr(status)));
+			goto invalidate_requests;
+		}
+
+		if (enc_ctx_num != cli->trans_enc_state->enc_ctx_num) {
+			DEBUG(10, ("wrong enc_ctx %d, expected %d\n",
+				   enc_ctx_num,
+				   cli->trans_enc_state->enc_ctx_num));
+			status = NT_STATUS_INVALID_HANDLE;
+			goto invalidate_requests;
+		}
+
+		status = common_decrypt_buffer(cli->trans_enc_state,
+					       cli->evt_inbuf);
+		if (!NT_STATUS_IS_OK(status)) {
+			DEBUG(10, ("common_decrypt_buffer returned %s\n",
+				   nt_errstr(status)));
+			goto invalidate_requests;
+		}
+	}
+
+	if (!cli_check_sign_mac(cli, cli->evt_inbuf)) {
+		DEBUG(10, ("cli_check_sign_mac failed\n"));
+		status = NT_STATUS_ACCESS_DENIED;
+		goto invalidate_requests;
+	}
+
+	mid = SVAL(cli->evt_inbuf, smb_mid);
+
+	DEBUG(10, ("handle_incoming_pdu: got mid %d\n", mid));
+
+	for (req = cli->outstanding_requests; req; req = req->next) {
+		if (req->mid == mid) {
+			break;
+		}
+	}
+
+	buf_len = talloc_get_size(cli->evt_inbuf);
+	pdu_len = smb_len(cli->evt_inbuf) + 4;
+	rest_len = buf_len - raw_pdu_len;
+
+	if (req == NULL) {
+		DEBUG(3, ("Request for mid %d not found, dumping PDU\n", mid));
+
+		memmove(cli->evt_inbuf,	cli->evt_inbuf + raw_pdu_len,
+			buf_len - raw_pdu_len);
+
+		cli->evt_inbuf = TALLOC_REALLOC_ARRAY(NULL, cli->evt_inbuf,
+						      char, rest_len);
+		return;
+	}
+
+	if (buf_len == pdu_len) {
+		/*
+		 * Optimal case: Exactly one PDU was in the socket buffer
+		 */
+		req->inbuf = talloc_move(req, &cli->evt_inbuf);
+		goto done;
+	}
+
+	DEBUG(11, ("buf_len = %d, pdu_len = %d, splitting buffer\n",
+		   (int)buf_len, (int)pdu_len));
+
+	if (pdu_len < rest_len) {
+		/*
+		 * The PDU is shorter, talloc_memdup that one.
+		 */
+		req->inbuf = (char *)talloc_memdup(
+			req, cli->evt_inbuf, pdu_len);
+
+		memmove(cli->evt_inbuf,
+			cli->evt_inbuf + raw_pdu_len,
+			buf_len - raw_pdu_len);
+
+		cli->evt_inbuf = TALLOC_REALLOC_ARRAY(
+			NULL, cli->evt_inbuf, char, rest_len);
+	}
+	else {
+		/*
+		 * The PDU is larger than the rest,
+		 * talloc_memdup the rest
+		 */
+		req->inbuf = talloc_move(req, &cli->evt_inbuf);
+
+		cli->evt_inbuf = (char *)talloc_memdup(
+			cli, req->inbuf + raw_pdu_len,
+			rest_len);
+	}
+
+	if ((req->inbuf == NULL) || (cli->evt_inbuf == NULL)) {
+		status = NT_STATUS_NO_MEMORY;
+		goto invalidate_requests;
+	}
+
+ done:
+	async_req_done(req->async);
+	return;
+
+ invalidate_requests:
+
+	DEBUG(10, ("handle_incoming_pdu: Aborting with %s\n",
+		   nt_errstr(status)));
+
+	for (req = cli->outstanding_requests; req; req = req->next) {
+		async_req_error(req->async, status);
+	}
+	return;
+}
+
+/*
+ * fd event callback. This is the basic connection to the socket
+ */
+
+static void cli_state_handler(struct event_context *event_ctx,
+			      struct fd_event *event, uint16 flags, void *p)
+{
+	struct cli_state *cli = (struct cli_state *)p;
+	struct cli_request *req;
+
+	DEBUG(11, ("cli_state_handler called with flags %d\n", flags));
+
+	if (flags & EVENT_FD_READ) {
+		int res, available;
+		size_t old_size, new_size;
+		char *tmp;
+
+		res = ioctl(cli->fd, FIONREAD, &available);
+		if (res == -1) {
+			DEBUG(10, ("ioctl(FIONREAD) failed: %s\n",
+				   strerror(errno)));
+			goto sock_error;
+		}
+
+		if (available == 0) {
+			/* EOF */
+			goto sock_error;
+		}
+
+		old_size = talloc_get_size(cli->evt_inbuf);
+		new_size = old_size + available;
+
+		if (new_size < old_size) {
+			/* wrap */
+			goto sock_error;
+		}
+
+		tmp = TALLOC_REALLOC_ARRAY(cli, cli->evt_inbuf, char,
+					   new_size);
+		if (tmp == NULL) {
+			/* nomem */
+			goto sock_error;
+		}
+		cli->evt_inbuf = tmp;
+
+		res = recv(cli->fd, cli->evt_inbuf + old_size, available, 0);
+		if (res == -1) {
+			DEBUG(10, ("recv failed: %s\n", strerror(errno)));
+			goto sock_error;
+		}
+
+		DEBUG(11, ("cli_state_handler: received %d bytes, "
+			   "smb_len(evt_inbuf) = %d\n", (int)res,
+			   smb_len(cli->evt_inbuf)));
+
+		/* recv *might* have returned less than announced */
+		new_size = old_size + res;
+
+		/* shrink, so I don't expect errors here */
+		cli->evt_inbuf = TALLOC_REALLOC_ARRAY(cli, cli->evt_inbuf,
+						      char, new_size);
+
+		while ((cli->evt_inbuf != NULL)
+		       && ((smb_len(cli->evt_inbuf) + 4) <= new_size)) {
+			/*
+			 * we've got a complete NBT level PDU in evt_inbuf
+			 */
+			handle_incoming_pdu(cli);
+			new_size = talloc_get_size(cli->evt_inbuf);
+		}
+	}
+
+	if (flags & EVENT_FD_WRITE) {
+		size_t to_send;
+		ssize_t sent;
+
+		for (req = cli->outstanding_requests; req; req = req->next) {
+			to_send = smb_len(req->outbuf)+4;
+			if (to_send > req->sent) {
+				break;
+			}
+		}
+
+		if (req == NULL) {
+			event_fd_set_not_writeable(event);
+			return;
+		}
+
+		sent = send(cli->fd, req->outbuf + req->sent,
+			    to_send - req->sent, 0);
+
+		if (sent < 0) {
+			goto sock_error;
+		}
+
+		req->sent += sent;
+
+		if (req->sent == to_send) {
+			return;
+		}
+	}
+	return;
+
+ sock_error:
+	for (req = cli->outstanding_requests; req; req = req->next) {
+		req->async->state = ASYNC_REQ_ERROR;
+		req->async->status = map_nt_error_from_unix(errno);
+	}
+	TALLOC_FREE(cli->fd_event);
+	close(cli->fd);
+	cli->fd = -1;
+}
+
+/*
+ * Holder for a talloc_destructor, we need to zero out the pointers in cli
+ * when deleting
+ */
+struct cli_tmp_event {
+	struct cli_state *cli;
+};
+
+static int cli_tmp_event_destructor(struct cli_tmp_event *e)
+{
+	TALLOC_FREE(e->cli->fd_event);
+	TALLOC_FREE(e->cli->event_ctx);
+	return 0;
+}
+
+/*
+ * Create a temporary event context for use in the sync helper functions
+ */
+
+struct cli_tmp_event *cli_tmp_event_ctx(TALLOC_CTX *mem_ctx,
+					struct cli_state *cli)
+{
+	struct cli_tmp_event *state;
+
+	if (cli->event_ctx != NULL) {
+		return NULL;
+	}
+
+	state = talloc(mem_ctx, struct cli_tmp_event);
+	if (state == NULL) {
+		return NULL;
+	}
+	state->cli = cli;
+	talloc_set_destructor(state, cli_tmp_event_destructor);
+
+	cli->event_ctx = event_context_init(state);
+	if (cli->event_ctx == NULL) {
+		TALLOC_FREE(state);
+		return NULL;
+	}
+
+	cli->fd_event = event_add_fd(cli->event_ctx, state, cli->fd,
+				     EVENT_FD_READ, cli_state_handler, cli);
+	if (cli->fd_event == NULL) {
+		TALLOC_FREE(state);
+		return NULL;
+	}
+	return state;
+}
+
+/*
+ * Attach an event context permanently to a cli_struct
+ */
+
+NTSTATUS cli_add_event_ctx(struct cli_state *cli,
+			   struct event_context *event_ctx)
+{
+	cli->event_ctx = event_ctx;
+	cli->fd_event = event_add_fd(event_ctx, cli, cli->fd, EVENT_FD_READ,
+				     cli_state_handler, cli);
+	if (cli->fd_event == NULL) {
+		return NT_STATUS_NO_MEMORY;
+	}
+	return NT_STATUS_OK;
+}