summaryrefslogtreecommitdiffstats
path: root/src/vty/telnet_interface.c
blob: dc23b12a4e70e90612684fb8494459b744e5bdb6 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
/* (C) 2009-2010 by Holger Hans Peter Freyther <zecke@selfish.org>
 * (C) 2010 by Sylvain Munaut <tnt@246tNt.com>
 * All Rights Reserved
 *
 * SPDX-License-Identifier: GPL-2.0+
 *
 * 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 2 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, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 */

#include <sys/socket.h>
#include <netinet/in.h>
#include <errno.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>

#include <osmocom/core/msgb.h>
#include <osmocom/core/socket.h>
#include <osmocom/core/talloc.h>
#include <osmocom/core/logging.h>
#include <osmocom/core/signal.h>

#include <osmocom/vty/telnet_interface.h>
#include <osmocom/vty/buffer.h>
#include <osmocom/vty/command.h>

/*! \file telnet_interface.c
 *  Telnet interface towards Osmocom VTY
 *
 *  This module contains the code implementing a telnet server for VTY
 *  access.  This telnet server gets linked into each libosmovty-using
 *  process in order to enable interactive command-line introspection,
 *  interaction and configuration.
 *
 *  You typically call \ref telnet_init or \ref telnet_init_dynif once
 *  from your application code to enable this.
 */

/* per connection data */
LLIST_HEAD(active_connections);

static void *tall_telnet_ctx;

/* per network data */
static int telnet_new_connection(struct osmo_fd *fd, unsigned int what);

static struct osmo_fd server_socket = {
	.when	    = OSMO_FD_READ,
	.cb	    = telnet_new_connection,
	.priv_nr    = 0,
};

/*! Initialize telnet based VTY interface listening to 127.0.0.1
 *  \param[in] tall_ctx \ref talloc context
 *  \param[in] priv private data to be passed to callback
 *  \param[in] port TCP port number to bind to
 */
int telnet_init(void *tall_ctx, void *priv, int port)
{
	return telnet_init_dynif(tall_ctx, priv, "127.0.0.1", port);
}

/*! Initialize telnet based VTY interface
 *  \param[in] tall_ctx \ref talloc context
 *  \param[in] priv private data to be passed to callback
 *  \param[in] ip IP to listen to ('::1' for localhost, '::0' for all, ...)
 *  \param[in] port TCP port number to bind to
 */
int telnet_init_dynif(void *tall_ctx, void *priv, const char *ip, int port)
{
	int rc;

	tall_telnet_ctx = talloc_named_const(tall_ctx, 1,
			"telnet_connection");

	rc = osmo_sock_init_ofd(
			&server_socket,
			AF_UNSPEC, SOCK_STREAM, IPPROTO_TCP,
			ip, port, OSMO_SOCK_F_BIND
			);

	server_socket.data = priv;

	if (rc < 0) {
		LOGP(DLGLOBAL, LOGL_ERROR, "Cannot bind telnet at %s %d\n",
		     ip, port);
		return -1;
	}

	LOGP(DLGLOBAL, LOGL_NOTICE, "Available via telnet %s %d\n", ip, port);
	return 0;
}

/*! Initializes telnet based VTY interface using the configured bind addr/port.
 *  \param[in] tall_ctx \ref talloc context
 *  \param[in] priv private data to be passed to callback
 *  \param[in] default_port TCP port number to bind to if not explicitely configured
 */
int telnet_init_default(void *tall_ctx, void *priv, int default_port)
{
	return telnet_init_dynif(tall_ctx, priv, vty_get_bind_addr(),
				 vty_get_bind_port(default_port));
}


extern struct host host;

/*! close a telnet connection */
int telnet_close_client(struct osmo_fd *fd)
{
	struct telnet_connection *conn = (struct telnet_connection*)fd->data;

	close(fd->fd);
	osmo_fd_unregister(fd);

	if (conn->dbg) {
		log_del_target(conn->dbg);
		talloc_free(conn->dbg);
	}

	llist_del(&conn->entry);
	talloc_free(conn);
	return 0;
}

static int client_data(struct osmo_fd *fd, unsigned int what)
{
	struct telnet_connection *conn = fd->data;
	int rc = 0;

	if (what & OSMO_FD_READ) {
		conn->fd.when &= ~OSMO_FD_READ;
		rc = vty_read(conn->vty);
	}

	/* vty might have been closed from vithin vty_read() */
	if (rc == -EBADF)
		return rc;

	if (what & OSMO_FD_WRITE) {
		rc = buffer_flush_all(conn->vty->obuf, fd->fd);
		if (rc == BUFFER_EMPTY)
			conn->fd.when &= ~OSMO_FD_WRITE;
	}

	return rc;
}

static int telnet_new_connection(struct osmo_fd *fd, unsigned int what)
{
	struct telnet_connection *connection;
	struct sockaddr_in sockaddr;
	socklen_t len = sizeof(sockaddr);
	int new_connection = accept(fd->fd, (struct sockaddr*)&sockaddr, &len);
	int rc;

	if (new_connection < 0) {
		LOGP(0, LOGL_ERROR, "telnet accept failed\n");
		return new_connection;
	}

	connection = talloc_zero(tall_telnet_ctx, struct telnet_connection);
	connection->priv = fd->data;
	connection->fd.data = connection;
	connection->fd.fd = new_connection;
	connection->fd.when = OSMO_FD_READ;
	connection->fd.cb = client_data;
	rc = osmo_fd_register(&connection->fd);
	if (rc < 0) {
		talloc_free(connection);
		return rc;
	}
	llist_add_tail(&connection->entry, &active_connections);

	connection->vty = vty_create(new_connection, connection);
	if (!connection->vty) {
		LOGP(0, LOGL_ERROR, "couldn't create VTY\n");
		/* vty_create() is already closing the fd if it returns NULL */
		talloc_free(connection);
		return -1;
	}

	return 0;
}

/*! callback from core VTY code about VTY related events */
void vty_event(enum event event, int sock, struct vty *vty)
{
	struct vty_signal_data sig_data = { 0, };
	struct telnet_connection *connection = vty->priv;
	struct osmo_fd *bfd;

	if (vty->type != VTY_TERM)
		return;

	sig_data.event = event;
	sig_data.sock = sock;
	sig_data.vty = vty;
	osmo_signal_dispatch(SS_L_VTY, S_VTY_EVENT, &sig_data);

	if (!connection)
		return;

	bfd = &connection->fd;

	switch (event) {
	case VTY_READ:
		bfd->when |= OSMO_FD_READ;
		break;
	case VTY_WRITE:
		bfd->when |= OSMO_FD_WRITE;
		break;
	case VTY_CLOSED:
		/* vty layer is about to free() vty */
		telnet_close_client(bfd);
		break;
	default:
		break;
	}
}

/*! Close all telnet connections and release the telnet socket */
void telnet_exit(void) 
{
	struct telnet_connection *tc, *tc2;

	llist_for_each_entry_safe(tc, tc2, &active_connections, entry)
		telnet_close_client(&tc->fd);

	osmo_fd_unregister(&server_socket);
	close(server_socket.fd);
	talloc_free(tall_telnet_ctx);
}