1 /*
2 Unix SMB/CIFS implementation.
3 Infrastructure for async SMB client requests
4 Copyright (C) Volker Lendecke 2008
5
6 This program is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 3 of the License, or
9 (at your option) any later version.
10
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
15
16 You should have received a copy of the GNU General Public License
17 along with this program. If not, see <http://www.gnu.org/licenses/>.
18 */
19
20 #include "includes.h"
21 #include "system/network.h"
22 #include "lib/async_req/async_sock.h"
23 #include "read_smb.h"
24 #include "lib/util/tevent_unix.h"
25 #include "libcli/smb/smb_constants.h"
26
27 /*
28 * Read an smb packet asynchronously, discard keepalives
29 */
30
31 struct read_smb_state {
32 struct tevent_context *ev;
33 int fd;
34 uint8_t *buf;
35 };
36
37 static ssize_t read_smb_more(uint8_t *buf, size_t buflen, void *private_data);
38 static void read_smb_done(struct tevent_req *subreq);
39
read_smb_send(TALLOC_CTX * mem_ctx,struct tevent_context * ev,int fd)40 struct tevent_req *read_smb_send(TALLOC_CTX *mem_ctx,
41 struct tevent_context *ev,
42 int fd)
43 {
44 struct tevent_req *result, *subreq;
45 struct read_smb_state *state;
46
47 result = tevent_req_create(mem_ctx, &state, struct read_smb_state);
48 if (result == NULL) {
49 return NULL;
50 }
51 state->ev = ev;
52 state->fd = fd;
53
54 subreq = read_packet_send(state, ev, fd, 4, read_smb_more, NULL);
55 if (subreq == NULL) {
56 goto fail;
57 }
58 tevent_req_set_callback(subreq, read_smb_done, result);
59 return result;
60 fail:
61 TALLOC_FREE(result);
62 return NULL;
63 }
64
read_smb_more(uint8_t * buf,size_t buflen,void * private_data)65 static ssize_t read_smb_more(uint8_t *buf, size_t buflen, void *private_data)
66 {
67 if (buflen > 4) {
68 return 0; /* We've been here, we're done */
69 }
70 return smb_len_tcp(buf);
71 }
72
read_smb_done(struct tevent_req * subreq)73 static void read_smb_done(struct tevent_req *subreq)
74 {
75 struct tevent_req *req = tevent_req_callback_data(
76 subreq, struct tevent_req);
77 struct read_smb_state *state = tevent_req_data(
78 req, struct read_smb_state);
79 ssize_t len;
80 int err;
81
82 len = read_packet_recv(subreq, state, &state->buf, &err);
83 TALLOC_FREE(subreq);
84 if (len == -1) {
85 tevent_req_error(req, err);
86 return;
87 }
88
89 if (CVAL(state->buf, 0) == NBSSkeepalive) {
90 subreq = read_packet_send(state, state->ev, state->fd, 4,
91 read_smb_more, NULL);
92 if (tevent_req_nomem(subreq, req)) {
93 return;
94 }
95 tevent_req_set_callback(subreq, read_smb_done, req);
96 return;
97 }
98 tevent_req_done(req);
99 }
100
read_smb_recv(struct tevent_req * req,TALLOC_CTX * mem_ctx,uint8_t ** pbuf,int * perrno)101 ssize_t read_smb_recv(struct tevent_req *req, TALLOC_CTX *mem_ctx,
102 uint8_t **pbuf, int *perrno)
103 {
104 struct read_smb_state *state = tevent_req_data(
105 req, struct read_smb_state);
106
107 if (tevent_req_is_unix_error(req, perrno)) {
108 tevent_req_received(req);
109 return -1;
110 }
111 *pbuf = talloc_move(mem_ctx, &state->buf);
112 tevent_req_received(req);
113 return talloc_get_size(*pbuf);
114 }
115