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/* (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;
char sock_name_buf[OSMO_SOCK_NAME_MAXLEN];
int rc;
/* FIXME: getsockname() always fails: "Bad file descriptor" */
rc = osmo_sock_get_name_buf(sock_name_buf, OSMO_SOCK_NAME_MAXLEN, fd->fd);
LOGP(DLGLOBAL, LOGL_INFO, "Closing telnet connection %s\n",
(rc <= 0) ? "r=NULL<->l=NULL" : sock_name_buf);
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);
char sock_name_buf[OSMO_SOCK_NAME_MAXLEN];
int rc;
if (new_connection < 0) {
LOGP(DLGLOBAL, LOGL_ERROR, "telnet accept failed\n");
return new_connection;
}
rc = osmo_sock_get_name_buf(sock_name_buf, OSMO_SOCK_NAME_MAXLEN, new_connection);
LOGP(DLGLOBAL, LOGL_INFO, "Accept()ed new telnet connection %s\n",
(rc <= 0) ? "r=NULL<->l=NULL" : sock_name_buf);
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(DLGLOBAL, 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;
}
bool vty_is_active(struct vty *vty)
{
struct telnet_connection *connection;
llist_for_each_entry(connection, &active_connections, entry) {
if (connection->vty == vty)
return true;
}
return false;
}
/*! 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;
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);
}
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